1.	B
[1]

2.	C
[1]

3.	A
[1]

4.	B
[1]

5.	A
[1]

6.	D
[1]

7.	C
[1]

8.	A
[1]

9.	D
[1]

10.	B
[1]

11.	A
[1]

12.	C
[1]

13.	D
[1]

14.	(a)	Award [1] for every two correct.

Enzyme	Source	Optimum pH	Substrate	Products	
Amylase	Salivary
gland	7	starch/amylose/
glycogen;	maltose/short
polysaccharides
/disaccharides
/dextrin;	
Lipase	Pancreas;	Allow any pH in range 7–9	Lipids	Fatty acids and
glycerol	
		2 max
 
(b)	rate of digestion at body temperature would be too slow / enzymes
increase the rate of digestion;
enzymes break large molecules down into small/soluble molecules;
for absorption/diffusion into blood;	2 max
 
(c)	labelled sac-shaped gall bladder with a duct;
tubule/(bile) duct shown connecting gall bladder directly to small
intestine/duodenum / tubule/(bile) duct merging with the pancreatic
duct before entering small intestine; Alternative answers are
accepted because of variations in human anatomy.
pancreas drawn with pancreatic duct connected to small intestine
and pancreas labelled;	3
A duct is preferred to a line, but since this is a diagram, both are acceptable.
[7]

15.	(a)	drugs used to down-regulate the menstrual cycle;
FSH injected to stimulate many follicles to develop;
HCG injected to cause the follicles to mature;
eggs are harvested/extracted (from the follicles/ovaries);
semen sample produced/collected;
semen is processed to concentrate it / healthy sperm selected
(swim-up test given);
ICSI/IntraCytoplasmic Sperm Injection where sperm is directly
injected into egg when low numbers of motility is a factor;
semen mixed with eggs in a dish/outside the body to allow fertilization;
incubated / kept at 37°C / allows embryos to develop (sufficiently
for implantation);
dish examined to choose healthiest embryo;
embryos placed in uterus/oviduct (using a catheter/long plastic tube);
one/two/three/up to four (in some countries) embryos implanted;
pregnancy test/scan used to see if procedure has been successful;
(used in cases of) blocked oviduct / low sperm count / need for genetic
screening /infertility / cannot become pregnant / need for donor embryo;	9 max
Accept other reasonable situations. Full marks may be awarded
only if an example is included in the answer.
 
(b)	females are carriers when they have dominant and recessive alleles
together;
recessive allele in carrier does not affect phenotype as dominant
allele also present;
gene is located on the X chromosome / gene is not located on Y
chromosome;
females are XX so can have dominant and recessive alleles/two
alleles of gene;
males are XY so only have dominant or recessive allele/one allele
of gene;
hemophilia/red-green colour blindness/other example of a sex-linked
characteristic;	4 max
 
(c)	(point) mutation of gene for hemoglobin;
CTC to CAC / GAG to GTG / substitution of T/thymine with A/adenine;
mRNA copy of gene is GUG instead of GAG;
valine instead of glutamic acid;
(in homozygotes) red blood cells become sickle-shaped;
(in homozygotes) less oxygen carried;
(in homozygotes) red blood cells do not survive long / burst / block
blood vessels/capillaries / circulatory problems may cause pain/
organ failure/example of symptom;
heterozygotes have malaria resistance;	5 max
(Plus up to [2] for quality)
[20]

16.	(a)	40 s/seconds (units required)	1
 
(b)	initially the heart rate decreases rapidly;
heart rate increases over the next seconds;
heart rate falls to its lowest level / reaches lowest level after
55 s/seconds / 35 s/seconds after start of dive;
in the last seconds before the dive ends, the heart rate increases;	2 max
 
(c)	anaerobic respiration because the tufted duck cannot breathe/
ventilate under water / replace oxygen that has been used;
aerobic respiration because the tufted duck uses stored oxygen;
both aerobic (at the beginning) and anaerobic (at the end) because
oxygen was used up during the dive;	1 max
To award [1], reason must be given.
 
(d)	200 (%)	1
 
(e)
Heart muscles	Flight muscles	
swimming at maximum speed causes increase in blood flow to heart muscles	swimming at maximum speed causes decrease in blood flow to flight muscles;	
swimming at normal speed, less blood flow to heart muscles (20 ml min–1) / swimming at maximum speed, more blood flow to heart muscles (24 ml min–1)	swimming at normal speed, greater blood flow to flight muscles (39 ml min–1) / swimming at maximum speed, less blood flow to flight muscles (18 ml min–1);	
small change in blood flow to heart muscles when changing speed (4 ml min–1 more)	big change/almost half amount of blood flow to flight muscles when changing speed (22 ml min–1 less);	
	Award [1] for each correct row. Answers do not need to be shown
in a table format, but must be comparative statements.	2 max
 
(f)	legs/leg muscles need more energy/ATP for fast swimming;
legs/leg muscles need more blood to provide oxygen/glucose for energy;
(the legs need more blood) to remove carbon dioxide;
the heart needs more blood to pump faster;
intestines/kidneys/flight muscles have less blood to allow for
increased flow to heart/legs;	2 max

(g)	blood flow decreases;
as heart rate is seen to decrease in the first graph;
as lower heart rate means less requirement for oxygen/nutrients/
blood/removal of waste;	2 max
 
(h)	adrenaline / epinephrine / noradrenaline / norepinephrine	1
[12]

17.	(a)	HIV/human immunodeficiency virus;
reduces the effectiveness of the immune system / reduction in
the number of active lymphocytes / infects T-(helper) cells/
lymphocytes;
loss of the ability to produce antibodies;
leaving the infected person susceptible to other infectious
diseases / AIDS is an accumulation of opportunistic diseases;
can be transmitted by sexual intercourse/exchange of body
fluids with an infected person;
can be transmitted by blood transfusion/blood products from
infected person;
mothers can transmit to children while breast feeding/
during pregnancy/birth;
sharing hypodermic needles that have not been sterilized;	5 max
 
(b)	phagocytic leucocyte occurs in blood and body tissue fluids;
phagocytic leucocyte detects pathogen/foreign material;
leucocyte surrounds/engulfs pathogen / endocytosis / phagocytosis;
membrane forms around pathogen to form a vacuole;
lysosomes digest contents of vacuoles;	4 max

(c)	homeostasis involves maintaining a constant internal environment;
involves the concept of negative feedback;
a deviation from the norm is the stimulus to trigger the mechanisms
to restore the norm / OWTTE;
body temperature in mammals must be maintained at a constant
level for enzymes;
controlled by the hypothalamus / hypothalamus as a thermostat;
too hot causes vasodilation so more heat is lost from skin;
too hot causes sweating as evaporation of sweat leads to cooling;
too cold causes shivering/muscle contraction as (increased
metabolic rate) generates heat;
too cold causes vasoconstriction so less heat lost from skin;
liver/muscles can generate heat which is distributed around the
body by blood;
hair can trap air which insulates against heat loss (goose bumps);
behavioural example of heat retention;
(e.g. adding layers of clothes, jumping up and down,
huddling in groups)	9 max
(Plus up to [2] for quality)
[20]

18.	(a)	Ascorbic acid: 2 mg (units are needed)
Dehydroascorbic acid: 2 mg (units are needed)	1
Both required for the mark.
 
(b)	400 (%) (working not required)	1
 
(c)	more ascorbic acid (40 mg) than dehydroascorbic acid (33 mg)
is released/excreted;
more dehydroascorbic acid (16 mg) than ascorbic acid (10 mg)
is released/excreted in the first three hours / dehydroascorbic
acid peaks before ascorbic acid;
from six hours onwards more ascorbic acid is released than
dehydroascorbic acid;
maximum release of dehydroascorbic acid at three hours
whereas maximum release of ascorbic acid at six hours;
ascorbic acid release rises then falls whereas dehydroascorbic
release falls (until 12 hours after loading);	2 max
 
(d)	genetic variability / differences in vitamin C metabolism /
differences in vitamin C requirements / differences in levels
of uptake into blood / size/weight of individuals	1

(e)	both chemical forms are released/excreted so supplements
need to be given regularly;
using dehydroascorbic acid instead of ascorbic acid does
not improve vitamin C retention / dehydroascorbic acid could
be marginally better as less is excreted;
study only looks at young/healthy/female subjects;
period of vitamin C deficiency is too short / need a longer
period to allow scurvy to develop;	2 max
[7]

19.	(a)	(i)	BMI = 74.0 kg / (1.80 m)2;
= 22.8 kg m–2; (unit required) 	1 max
 
(ii)	normal weight (allow ECF)	1
 
(b)	diet rich in carbohydrate/fat;
too much food intake / unbalanced diet / food cheap and readily available;
sedentary lifestyle / lack of training/exercise;
genetic disposition/disorder;
malfunction of hunger centre;	3 max
[5]

release falls (until 12 hours after loading);	2 max
 
(d)	genetic variability / differences in vitamin C metabolism /
differences in vitamin C requirements / differences in levels
of uptake into blood / size/weight of individuals	1
 
(e)	both chemical forms are released/excreted so supplements
need to be given regularly;
using dehydroascorbic acid instead of ascorbic acid does
not improve vitamin C retention / dehydroascorbic acid could
be marginally better as less is excreted;
study only looks at young/healthy/female subjects;
period of vitamin C deficiency is too short / need a longer
period to allow scurvy to develop;	2 max
[7]

20.	(a)	first milk/colostrum/breast milk of humans contains antibodies;
human milk contains lactose (rather than glucose/glucose polymers);
human milk contains more suitable fatty acids;
human milk contains human proteins / appropriate protein
concentrations / more easily digested proteins; Accept “artificial
milk contains bovine/soya proteins”.
bonding between the mother and child;
breastfeeding avoids allergies to proteins in cow’s milk;
human milk naturally sterile;
health benefits for mother e.g. loss of weight / breast cancer protection;	2 max
Accept reverse arguments for any of the above points if clear.
 
(b)	decreasing responsiveness to insulin;
high blood glucose;
glucose in urine;
loss of weight / tiredness;
increased production of urine;
dehydration and thirst;	1 max
 
(c)	regulate diet/total calorie intake and exercise to ensure a balanced
energy budget;
low fat diet to avoid weight gain;
consume complex carbohydrates to ensure gradual release of glucose
into blood/avoid sudden effect on blood glucose;
eat regular small meals to ensure a steady supply of glucose;
do not go for long periods without meals to avoid large drop in blood
glucose;
consume foods (with low glycemic index) to avoid abrupt changes
in blood glucose;	3 max
Each statement must be justified to gain a mark.
[6]

21.	(a)	12.6 cm3 beat–1 (units required)	1
 
(b)	muscles working harder / require more O2 / moving the whole body;
intensity of exercise (on weight-bearing machines) is higher;
muscles supporting body weight are also active;	1 max
 
(c)	weight-bearing machines require higher energy expenditure
(than non weight-bearing);
body trec highest energy expenditure and stationary cycle lowest;
large standard deviations for all machines / large range of values
amongst participants / no clear trend apparent;	2 max

(d)	Advantages: [2 max]
energy expenditure is higher so greater weight loss/greater use of
carbohydrates/fats;
shorter recovery times needed due to higher oxygen supply;
heart rate is increased but not to an excessive level;
higher ventilation rate means more aerobic respiration (although
lactate levels indicate more anaerobic respiration as well);
	Disadvantages:
possible strain on joints;
body trec results in very high blood lactate values;
increased heart rate potentially dangerous for obese subjects / too
much stress for obese subjects (as indicated by high lactate levels);	3 max
[7]

22.	(a)	cardiac output/stroke volume increases more rapidly during exercise;
heart rate increases more gradually during exercise;
recovery to normal cardiac output after exercise is faster;
resting pulse rate is lower;	2 max
 
(b)	lactate can be converted to pyruvate in liver;
pyruvate can then be converted into glucose (Cori cycle);
glucose/pyruvate can then be used for aerobic respiration;
additional oxygen is supplied during deep/fast ventilations after exercise;	2 max
 
(c)	increase blood flow to muscles;
stretch tendons and ligaments;
improve flexibility of joints;
little scientific evidence for the need to warm up / strong belief
amongst athletes in the effectiveness of warm up / placebo effect
during scientific trials / mental preparation for intense exercise;	2 max
[6]

23.	(a)	Award [1] for each structure clearly drawn and correctly labelled.
Z lines;
actin filaments;
myosin filaments with heads;
light bands and dark bands;	3 max

(b)	Ca2+ ions released when a nerve impulse arrives at the muscle;
Ca2+ ions are released from the sarcoplasmic reticulum;
binding sites for myosin heads are exposed;
this allows cross-bridges between myosin and actin to form;	2 max
[5]

24.	(a)	(i)	summer	1
 
(ii)	Geelong and (Southeast) Queensland (both needed)	1
 
(iii)	(40 – 8) = 32% (accept answers in the range of 31% to 33%)	1
 
(b)	similarity:
none of the locations are deficient in Summer;
Geelong and (Southeast) Queensland have similar prevalence/levels
of deficiency at all times of the year;
	difference:
only Tasmania shows a deficiency in autumn;
Tasmania shows the highest prevalence of deficiency;
(Southeast) Queensland shows less prevalence/levels of deficiency overall;	3 max
To award [3], answers must address at least one similarity and
one difference.
 
(c)	diets rich in vitamin D could raise vitamin D levels; (vice versa)
use of sunscreen/staying out of the sun/hats/clothing can reduce
the production of vitamin D by the skin; (vice versa)
use of dietary supplements containing vitamin D can reduce
deficiency levels;	2 max
[8]

25.	(a)	(per 100 g) fat contains more energy than protein or carbohydrate /
fat has higher energy content (per 100 g);
fat contains (approximately) twice the number of joules/energy
per gram than proteins and/or carbohydrates;
(per 100 g) fats have approximately 4000 kJ, whereas carbohydrates
have 1760 kJ and proteins have 1720 kJ;	1 max
 
(b)	lack of blood plasma proteins and tissue fluid retention/abdominal
bloating/swollen abdomen;
kwashiorkor/marasmus develops;
poor growth and development (among children);
(often) mental retardation;
lethargic/little interest in surroundings;
wasting of muscle / thin muscles;	2 max
 
(c)	(consuming animals or animal products) may reduce problems
of malnutrition/hunger;
appropriate use of antibiotics improves
health of livestock/may cause antibiotic resistance/side effects/allergies;
killing animals is wrong/against (some) religious beliefs;
overeating leads to health problems/cardiovascular disease/obesity;
animal foods are from organisms higher up the food chain/more
energy (per acre) available to humans with a plant diet than
with an animal diet/animal diet has a higher ecological footprint; (vice versa)
poor treatment of animals raised for food / example of ill treatment
of animals;
destruction of ecosystems;
introduction of hormones, into the human food supply/environment;
hunting could lead to species extinction;
eating animals/animal products may be necessary for human survival;	4 max
[7]

26.	cause: [1 max]
a genetic variation/mutation;
change in gene coding for tyrosine hydroxylase;
	consequences: [1 max]
results in a failure to metabolize phenylalanine into tyrosine;
results in high levels of ketones in the blood and urine;
results in mental retardation/brain damage;
	diagnosis: [1 max]
can be made by a simple blood test for the level of phenylalanine;
diagnosis can be made shortly after birth;	3 max
[3]

27.	(a)	(i)	standing position	1
 
(ii)	leg muscles are not pumping/contracting to help return
of blood to the heart;
gravity pulls the blood back towards feet / circulation
must overcome gravity to return blood to heart;	1 max
 
(b)	340 (arbitrary units)	1
 
(c)	better oxygenation enhances muscle metabolism;
better blood flow/cardiovascular fitness prevents pooling/swelling
of ankles and feet/varicose veins;
prevention of thrombosis;
maintenance of muscle strength from better circulation;
maintenance of muscle strength from use of muscles;	3 max
[6]

28.	(a)	(i)	physical condition of a body that allows it to perform
exercise of a particular type	1
 
(ii)	speed is rate of movement;
stamina is the capacity for sustained performance/exercise;
measures of fitness/agility/strength can be used to show
improvement in performance;
shortening of time for heart to return to resting rate;	2 max
 
(b)	training causes enlargement/strengthening of heart muscle
due to increased work/contractions;
(this strengthening is) especially in the left ventricle;
cardiac output increases as a result of increased heart rate
(during training);
cardiac output increases as a result of increased stroke
volume (due to stronger heart muscle);
greater movement of blood improves delivery of oxygen for
aerobic respiration (to the heart muscle);
(basal) heart rate of a trained individual is lower than that
of an untrained individual due to a stronger heart muscle;	3 max
[6]

29.	C
[1]

30.	D
[1]

31.	B
[1]

32.	C
[1]

33.	A
[1]

34.	C
[1]

35.	D
[1]

36.	C
[1]

37.	A
[1]

38.	C
[1]

39.	B
[1]

40.	B
[1]

41.	(a)	sweat/perspiration secreted/produced;
evaporation of sweat causes cooling/heat to be removed from skin;
skin arterioles become wider/vasodilate;
more blood flows through (capillaries in) the skin;
heat carried to the skin / skin becomes warmer / skin reaches core
temperature;
more heat lost by skin to the environment;
behavioural responses / reduced activity / other example of
behaviour resulting in cooling;	5 max
 
(b)	ADH is secreted when the solute concentration of the blood is
too high/OWTTE/converse;
ADH makes the collecting duct more permeable to water / when
not secreted the collecting duct is less permeable to water;
(causes) more aquaporins in the (membranes of cells in the)
collecting duct;
collecting duct passes through medulla;
increasing salt concentration of medulla / hypertonic medulla;
leading to osmosis / more water is reabsorbed (from the collecting
duct);
so volume of urine is less / urine more concentrated;
(without ADH) higher flow rates so less time for water reabsorbtion;
(without ADH) dilute / large volume of urine is produced;	5 max
 
(c)	ventilation occurs within the lungs;
trachea divides to form two bronchi;
bronchi divide to form bronchioles;
several divisions of bronchioles;
alveoli connected to bronchioles;
trachea/bronchi/bronchioles/airways lined with cilia/ciliated epithelium;
diaphragm and intercostal muscles;
trachea/bronchi have rings/c-shaped pieces of cartilage;
alveolus is an (air) sac;
very small / diameter is (about) 100 μm;
many alveoli so large total surface area;
wall of alveolus is a single layer of cells;
cells in alveolus wall are very thin;
surrounded by a network of capillaries;
some (larger) cells in the wall secrete fluid/surfactant/natural detergent;	8 max
Award any of the above points if clearly drawn in a diagram.
(Plus up to [2] for quality)
[20]

42.	(a)	Answers do not need to be shown in a table format.
	Spermatogenesis	Oogenesis	
number of gametes produced	many / millions per day 	one per month/menstrual cycle/28 days / about 400 eggs per life time;	
products of meiosis	four / equal division of the cytoplasm / no polar bodies	one / unequal division of the cytoplasm / polar bodies;	
start of process	at puberty	begins during fetal development;	
duration of production	throughout adult life	ends at menopause;	
timing of release	produced continuously / released during ejaculation	released at ovulation / in the middle of the menstrual cycle;	
both spermatogenesis and oogenesis involve meiosis;	
both produce haploid cells/nuclei;	
both occur in gonads	occurs in testes	occurs in ovaries;	
		5 max
 
(b)	meiosis;
independent assortment/random orientation of bivalents/pairs of chromosomes/homologous chromosomes;
in metaphase I;
223/2n possible combinations (where n is the haploid number of chromosomes);
crossing over / recombination of linked genes;
during prophase I;
can occur anywhere along a chromosome;
random orientation of chromatids (in metaphase II);
(gene) mutations may occur;	5 max

(c)	drugs used to (down-)regulate/stop the menstrual cycle;
hormones/FSH injected to stimulate many follicles to develop;
HCG injected to cause the follicles to mature;
eggs are harvested/extracted from the follicles/ovaries;
semen/sperm sample produced/collected;
semen is processed to concentrate it / sperm screened/given a
swim-up test;
semen/sperm mixed with eggs/oocyte / in a dish/in glass;
fertilization occurs;
embryos/blastocyst placed in uterus/oviduct (using a catheter/
long plastic tube);
Do not accept fertilized egg or zygote.
one/two/three/up to four (in some countries) embryos implanted;
pregnancy test/scan used to see if procedure has been successful /
genetic screening to assess health of fetus;
(used in cases of) blocked oviduct / low sperm count;
need for donor embryo in cases of female infertility / donor
sperm in case of male infertility; Accept other reasonable situations.	8 max
(Plus up to [2] for quality)
[20]

43.	(a)	removal of waste products of cell reactions/metabolic activities/pathways	1
 
(b)	blood (in the glomerulus) under high pressure caused by difference
in diameter of (afferent and efferent) arterioles;
fluid plasma and small molecules forced into kidney tubule/
Bowman’s capsule/through fenestrations/basal membrane;
which prevent larger molecules/blood cells from passing through;	2 max
 
(c)	difference: fluid at II has less urea/glucose/oxygen/salts/ions/water;
similarity: fluid at II has same (amount of) proteins/blood cells as fluid at I;	2
Accept converse for both marking points.
[5]

44.	(a)	heat causes vasodilation of arterioles;
blood closer to surface so heat loss from skin;
heat causes sweating (from sweat glands);
evaporation of sweat leads to cooling;
cold causes vasoconstriction of arterioles;
less blood at surface so less heat loss from skin;
cold leads to less sweating/evaporation of water from skin / hair
becomes erect and traps air/goose bumps appear;
temperature receptors in skin transmit impulses to the hypothalamus;	5 max

(b)	level of progesterone falls before birth;
oxytocin secreted;
from pituitary;
this stimulates contractions of uterus;
uterine contraction/stretching of cervix/vagina stimulates secretion
of (more) oxytocin;
form of positive feedback;	4 max
 
(c)	vaccine is a modified/weakened/attenuated form of a pathogen /
contains antigens from pathogens;
vaccine injected/ingested/introduced to patient;
pathogen/antigens stimulates specific immune response called
primary/initial responses;
antigens stimulate macrophages/lymphocytes/T-cells;
which stimulate cloning of B-cells/plasma cells;
including development of memory (B-)cells;
that produce specific antibodies;
(upon second exposure) production of antibodies is much faster;
higher level of antibody production / person has immunity;
called secondary response;
labelled graph showing curve with higher slope/peak for secondary
response than primary response;
may need booster shot to maintain immunity;
this is an example of active/artificial immunity;	9 max
(Plus up to [2] for quality)
[20]

45.	(a)	0.13 (pH min–1) (Allow values between 0.125 and 0.135)	1
 
(b)	(DIDS) reduces the rate of decrease of (extracellular) pH;
rate of decrease reduced less than control cells / some SCL26A9
are not inhibited;	1 max
 
(c)	(hypothesis supported as) SCL26A9 in excess means more
transport of ions;
(hypothesis supported as) when inhibited there is less transport
of ions (needed to maintain neutral pH);	2
 
(d)	host cells increase transcription/protein synthesis to make more carriers	1
 
(e)	pH will fall;
SLC26A9 transports less chloride/hydrogen carbonate ions;	2
[7]

46.	(a)	atheroma/fatty deposits in arteries;
hardening of arteries/atherosclerosis/arteriosclerosis;
rough surface causes rupture of platelets;
clots form in coronary artery;	2 max
 
(b)	(i)	increase in CO2 concentration;
decrease in pH;	1 max
 
(ii)	graph drawn to left of A;
curve not sigmoid;	2
As shown below.

(c)	hemoglobin absorbed by phagocytes/Kupffer cells;
split into heme and globins;
globin hydrolysed/broken down to amino acids;
iron removed from heme group / heme broken down to form bilirubin/
bile pigment;	2 max
[7]

47.	ADH secreted by hypothalamus;
by neurosecretory cells;
transport of ADH to posterior pituitary for storage;
through axon;
osmoreceptor cells monitor concentration of blood plasma;
if blood plasma too concentrated, ADH released;
kidney produces a small volume of hypertonic urine / reabsorption of
water in collecting ducts;
if plasma too dilute, ADH level of blood drops;
kidney produces a large volume of hypotonic urine / little water reabsorbed
from collecting ducts;
controlled by negative feedback;	6 max
[6]

48.	(a)	11.4% (accept answer in the range of 11.2% and 11.6%)	1
 
(b)	both lipids/LCT and LCT-MCT increase the percentage (of neutrophils
secreting H2O2);
LCT causes greater increase than LCT-MCT;
both lipids increase the percentage more at the higher concentration;
higher concentration increases effect of LCT more than LCT-MCT;
both (lipid solutions) have highest values at end of the incubation
period;	3 max
 
(c)	lipids are hydrophobic/insoluble so form droplets/coalesce/cause blockages	1
 
(d)	0.06 mg cm–3 concentration / LCT-MCT treatment is best/safest;
supplies lipids;
avoids high/harmful hydrogen peroxide levels / percentages;
LCT at 0.6 mg cm–3/higher level causes high/increasing hydrogen peroxide;
danger of side effects from hydrogen peroxide;
conclusions uncertain due to lack of data / example of unavailable
information;	3 max
[8]

49.	(a)	aorta;
carotid arteries;	2
 
(b)	carbonic anhydrase	1

(c)	curve shows saturation level at each partial pressure/concentration
of oxygen;
curve is to the left of hemoglobin/rises steeply;
myoglobin’s affinity for O2 is very great/greater than hemoglobin;
becomes saturated at low oxygen concentrations;
provides oxygen when it is very low/delays anaerobic respiration
in muscles;
curve not sigmoid because myoglobin only has one heme group/globin;	3 max
Accept response in the form of a clearly drawn and correctly labelled
diagram.
[6]

50.	ulcers are sores/inflamed/infected/damaged areas in the stomach wall;
strong relationship/association between H. pylori infection and ulcers;
H. pylori survives acid conditions in the stomach;
H. pylori lowers acidity of stomach / secretes urease which lowers acidity;
H. pylori secretes protease which damages stomach lining/protective mucus;
H. pylori allows damage of stomach lining by gastric acids;
H. pylori now treated as infectious disease / controlled as treatment for ulcers;
(prolonged) presence of stomach ulcers may lead to the formation of
tumours/cancer;
association/correlation between H. pylori infection and stomach cancer;	6 max
[6]

51.	A
[1]

52.	B
[1]

53.	D
[1]

54.	C
[1]

55.	A
[1]

56.	A
[1]

57.	B
[1]

58.	B
[1]

59.	(a)	I:	progesterone;
II:	estrogen;	2
 
(b)	FSH stimulates follicle development;
FSH stimulates estrogen secretion (by the follicle/ovary);	2
 
(c)	high levels of progesterone/estrogen inhibit FSH production (during pregnancy)	1
[5]

60.	(a)	atria collect blood from veins (vena cava/pulmonary);
collect blood while ventricles are contracting;
atria pump blood into ventricles/ensure ventricles are full;
ventricles pump blood into arteries/out of the heart;
ventricles pump blood at high pressure because of their thicker,
muscular walls;
mention of heart valves working with atria and ventricles to keep
blood moving;
left ventricle pumps blood to systems and right ventricle pumps
blood to lungs;
Both left and right ventricles with correct function required for
mark to be awarded.	4 max

(b)	thick wall to withstand high blood pressures/avoid bursting/leaks;
many muscle fibres to help pump blood;
many elastic fibres to stretch and pump blood after each heart beat;
narrow lumen to maintain high pressure/because blood flows along
rapidly;
thick outer layer of collagen to give strength/prevent aneurism;
no valves as pressure is high enough to prevent backflow;
endothelium/smooth inner lining to reduce friction;	5 max
 
(c)	one gene determines (ABO) blood groups / one gene for ABO blood groups;
genes have different/alternative forms called alleles;
there are three alleles (IA, IB and i) of the gene for (ABO) blood groups;
(ABO) blood groups are an example (of the effect of) multiple alleles
(in this instance three alleles can result in four phenotypes);
each individual has two alleles of the gene but only one is passed to
offspring;
alleles that are codominant both affect the phenotype in a heterozygote;
(alleles) IA and IB are codominant;
(alleles) IA and IB are dominant over i / i is recessive to IA and IB;
(genotypes) IAIA and IAi both give blood group A;
(genotypes) IBIB and IBi both give blood group B;
(genotype) IAIB gives blood group AB;
(genotype) ii/homozygous i gives blood group O;
example of a cross involving ABO blood groups;	9 max
	(Plus up to [2] for quality)
[20]

61.	(a)	At least one characteristic from each group is needed for maximum
credit.
bryophyta have no roots / only have rhizoids;
bryophyta have simple leaves/stems / only a thallus;
bryophyta produce spores in capsule;
byrophyta are nonvascular;
bryophyte exhibit (pronounced) alternation of generations / a
significant gametophyte generation;
	filicinophyta have roots, stems and leaves;
filicinophyta (often) have divided/pinnate leaves;
filicinophyta produce spores in sporangia/spores on the undersides of leaves;
filicinophyta exhibit alternation of generations;
filicinophyta have primitive vascular tissue / no true xylem and phloem;
	coniferophyta have woody stems;
coniferophyta (often) have narrow leaves/needles/scales;
coniferophyta produce seeds in cones/unenclosed seeds;
	angiospermophyta have flowers;
angiospermophyta have ovules in ovaries;
angiospermophyta produce seeds (with hard coats) in fruits;	9 max
 
(b)	starch is a large molecule;
large molecules/starch cannot be absorbed by the intestine/villi/epithelial
cells;
glucose produced by digestion of starch can be absorbed;
starch/glucose is a useful source of energy;
starch is not used in humans;
glucose is stored as glycogen not starch;
starch is not soluble/could not be transported by blood;	4 max

(c)	In the table below, information from both boxes on same line is
needed for 1 mark.
Differences [4 max]:
Prokaryotic cells	Eukaryotic cells	
no nucleus	nucleus;	
naked DNA	DNA associated with histone/protein;	
loop of DNA	strands of DNA;	
no mitochondria	mitochondria;	
70S/ smaller ribosomes	80S/ larger ribosomes;	
no/few internal membranes / no organelles	internal membranes/organelles/ Golgi/ER/lysosomes;	
smaller in size (approx. 1-10µm)	larger in size (approx. 10-100µm);	
cell wall (glycoprotein) present	sometimes present/not in animal cells;	
	Similarities: Award 1 mark for any combination of two different
items [2 max].
cytoplasm/plasma membrane/contains DNA/contains ribosomes	5 max
	(Plus up to [2] for quality)
[20]

62.	(a)	sodium/Na	1
 
(b)	unclear correlation between V and T;
depends on the nature of the substrate and its concentration;
sometimes high V with low T (e.g. experiment 1 for sucrose) /
sometimes high V with high T (e.g. experiment 2 for NaCl);	2 max
 
(c)	higher salt/NaCl concentrations increase T and V;
increase in puddling with increase in salt/NaCl;
no clear relationship between the number of visits and the
concentration of salt/NaCl;	2 max
 
(d)	(i)	sodium/Na	1

(ii)	retention of sodium/Na from laboratory solutions and natural
puddles;
definite loss of potassium from laboratory solutions but loss/gain
uncertain from natural puddles;
slight loss of magnesium from laboratory solutions and uncertain
gain/loss from natural puddles;
calcium uncertain in both cases / variation in data for calcium;
more conclusive results in laboratory solutions / conditions
more reliable in laboratory solutions / greater variation in
natural puddles;
Accept reference to error bars/ranges in data in place of
uncertainty.	3 max
 
(e)	males have longer/wider digestive tracts for greater absorption of fluid;
ileum of males has greater surface area;
which allows faster/more absorption in males than in females;	2 max
 
(f)	puddling provides needed sodium/Na because their (larval) food does not
supply enough sodium/Na;
sodium/Na needed for neural activity;
greater flight/neural activity in males than in females;
Accept other reasonable suggestions.	1 max
[12]

63.	(a)	pyruvate/pyruvic acid → lactate/lactic acid;
glucose→pyruvate/pyruvic acid→lactate/lactic acid;
Accept correct chemical equation with formula.	1 max
 
(b)	most cellular respiration is aerobic/requires oxygen / produces
carbon dioxide;
ventilation system exchanges gases between inhaled air and
lungs/blood stream;
ventilation system maintains high concentration gradient of
gases in alveoli/lungs;	2 max

(c)	estrogen line should show sharp drop after day 13, followed by gradual
rise to another peak (more rounded/stretched out and lower than day
13) followed by gradual drop to level similar to day 1;
progesterone line should gradually rise to rounded peak, followed by
gradual drop to level similar to day 1;	2
	example of diagram:

[5]

64.	(a)	Award [1] for each linked set of answers.
simple diffusion	facilitated diffusion	
energy requirement	none	none;	
direction of movement	down concentration gradient	down concentration gradient;	
specificity	not specific	specific;	
passage directly through phospholipid membrane	yes	no;	
protein channels	not required	required;	
solute	simple molecules / O2 / CO2	sugars/amino acids;	
solute binding to carriers	no	yes;	
speed of diffusion	slower	faster;	
		5 max

(b)	endocytosis occurs when a membrane encloses a target particle;
fluidity of membrane permits movement of membrane;
membrane sinks inwardly/forms pit/invaginates to enclose particle;
membrane seals back on itself / edges fuse;
one membrane layer / two phospholipid layers enclose particle making
vesicle;
inner phospholipid layer of (original) membrane becomes outer
phospholipid layer of vesicle membrane;
outer phospholipid layer of (original) membrane becomes inner
phospholipid layer of vesicle membrane;
vesicle breaks away from membrane/moves into cytoplasm;
changes in membrane shape require energy;
specific example of endocytosis (e.g. pinocytosis, phagocytosis);
Accept any of the above points in an annotated diagram.	5 max
 
(c)	resting membrane is polarized;
interior is –70 mV/negative relative to outside;
more sodium ions outside than inside;
more potassium ions inside than outside;
disturbance of membrane opens sodium ion channels;
sodium ions rush to inside of cell;
causing depolarization;
sodium ion channels shut;
potassium ion channels open;
potassium ions rush out;
helping to restore polarized state of membrane;
sodium–potassium pumps maintain polarity;
process repeated along the length of neuron / sodium ions diffuse between
region with an action potential and the region at resting potential;	8 max
	(Plus up to [2] for quality)
[20]

65.	(a)	(i)	middle ear infection	1
 
(ii)	gastroenteritis	1
 
(b)	significantly fewer visits to the doctor (for middle ear infections
and gastroenteritis) for infants fed breast milk only;
less medication prescribed (for middle ear infections) for infants
only breastfed / excess prescriptions for those not exclusively breastfed;
less hospitalization (for gastroenteritis) for infants only breastfed /
excess hospitalizations for those not exclusively breastfed;
little effect on frequency of lower respiratory infections for only
breastfed infants compared with partially breastfed infants;
significantly fewer follow-up visits (for middle ear infections) for
infants fed breast milk only;	2 max
 
(c)	breast milk contains maternal antibodies / lack of antibodies in
artificial milk;
antibodies provide protection against some viral and bacterial
infections / passive immunity;
breast milk has white blood cells/macrophages to fight infection;
breast milk has nutrients in correct proportions so easier to digest/less
likely to cause gastroenteritis;	2 max
[6]

66.	(a)	carbohydrate: 1760 kJ (per 100 g) fat: 4000 kJ (per 100 g) protein:
1720 kJ (per 100 g)
Accept values per gram – units required.
Must have correct figures.	1
 
(b)	may lead to obesity (which is risk factor for many health problems);
NOT weight gain
(obesity leads to) increased risk of coronary heart disease/gall bladder
disease/high blood pressure/diabetes/excess strain on joints; Accept CHD
may lead to increase in blood cholesterol/low density lipoprotein/LDL/
lipid levels;
deposits impede blood flow / cause diameter of blood vessel to decrease /
atherosclerosis / degeneration of artery walls;
health consequences depend on type of fat ingested — high saturated fat;	3 max
 
(c)	lack of blood plasma proteins;
leading to tissue fluid retention/swollen abdomen;
lethargic/little interest in surroundings;
thin muscles/flaky appearance of skin/sparse hair with lack of
pigmentation;
physical and mental development retarded;	2 max
[6]

67.	(a)	e.g. cod liver oil / fish liver oil / oily fish (accept correctly
named example) / egg yolk / fortified cereal / ONE named
dairy product (i.e. milk/cheese/ yoghurt)
Allow any two sources for the mark. Reject fish alone.	1

(b)	UV light/sunlight on skin causes chemical production of vitamin D;
UV too low in winter in high latitudes;
vitamin D stored in liver so can make enough to last several
months/through winter;
UV light can damage skin and cause skin cancer so exposure
needs to be limited;
use of sun-block will inhibit vitamin D production;
covering skin with clothing prevents UV reaching skin;
Accept reference to cultural/religious customs.	3 max
[4]

68.	distance food transported from site of production to the consumer;
used to assess environmental impact of food / local food has lower impact;
does not take into account number of trips from source/other costs such as
machinery used/fertilizers/pesticides;
transportation associated with CO2 emissions, with some transport producing
more than others (e.g. planes);
during famine, transport of food justifiable whatever food miles / on
humanitarian grounds;	2 max
[2]

69.	(a)	age / gender / diet / health or lifestyle / initial fitness levels
Allow any three factors for the mark.	1
 
(b)	as workload increases heart rate increases / positive relationship
(but only to a point);
graphs level off/plateau/reach maximum of approximately
180 beats minute–1;
increase is not linear / s-shaped curve / slow increase at low workloads;	2 max
 
(c)	(i)	130 –115 = 15 beats minute–1 (decrease after training)
Allow 14–18 beats minute–1. Units required.	1
 
(ii)	training group showed lower heart rate/beats minute–1 (at
workloads below 180 W);
higher workloads (180 W+) seemed to show little or no
difference/heart rate the same;
training increases the maximum intensity at which exercise can
be done;	2 max
[6]

70.	(a)	(i)	biceps and triceps correctly labelled;
(biceps = muscle on right, triceps = muscle on left)
Both needed for mark.	1
 
(ii)	(cartilage is hard but flexible) able to absorb mechanical shocks /
allows bones to pivot or move smoothly	1
 
(b)	ATP binds to myosin heads;
ATP binding causes cross bridges to break/heads detach from binding
site;
ATP broken down/hydrolysed to ADP + Pi, causing myosin heads to
change angle/become “cocked”;
myosin heads attach to binding sites on actin filament further along
sarcomere;
ADP + Pi released and myosin heads push actin filament along/power
stroke occurs;
Allow ONE mark if there is a general understanding of the role of ATP
in the sliding of filaments but without specific details.	3 max
[5]

71.	(a)	volume of air taken in or out with each (rhythmic/quiet/resting)
inhalation or exhalation	1
 
(b)	reduced ventilation / breathing rate at rest;
maximum ventilation rate increases;
vital capacity may increase;
dilated/more open blood capillaries around the alveoli;
increased efficiency of gas exchange (in alveoli);
strengthen muscles used for ventilation (diaphragm and intercostals);	3 max
[4]

72.	warm-up routines are series of exercises/stretches done before the main work out;
cause muscle temperature to increase / stimulates blood flow;
more oxygen supplied so increased respiration / more vigorous / rapid contractions;
(thought to be) necessary to prevent damage to muscles/tendons;
little or no scientific evidence to support belief in need to warm up;
difficult to conduct controlled experiments without a placebo effect;
possible psychological preparation;	3 max
[3]

73.	(a)	higher BMI increases risk of type II diabetes / risk increases as
the BMI increases;
greater risk for women than for men / men have a lower risk
than women;
values above 25 kg m–2 increase the risk of diabetes exponentially /
BMI below25 kg m–2 shows minimal risk;	2 max
 
(b)	21% (allow answers in the range of 20% to 22%)	1

	Information must be indicated on the graph.	1
 
(d)	moderate portions of food to avoid fluctuations in blood sugar levels;
regular mealtimes to avoid fluctuations in blood sugar levels;

include carbohydrates with a low glycemic index; (accept reverse for high)
include fibre-rich foods to slow absorption of sugar;
limit saturated/trans fats/cholesterol because diabetes increases risk of
coronary heart disease;	4 max
[8]

74.	(a)	human milk contains human proteins while artificial milk contains soya/
bovine proteins / more proteins in artificial milk;
in human milk, fatty acids are derived from human butterfat rather than
vegetable oils;
human milk has antibodies/provides immunity but artificial milk does not;
human milk contains lactose whereas artificial milk does not;
artificial milk contains more iron;	2 max
 
(b)	Asian groups: rice;
Pacific Islanders: cassava;
African groups: cassava;
European: wheat/potatoes;
Euro-American groups: wheat/potatoes;
Native Americans: corn/maize;
Andean groups: potatoes/rice;
other verifiable examples can be used;
More specific ethnic group names would be appropriate.	2 max

(c)	too much fat may result in weight gain/obesity;
(obesity) increases risk of coronary heart disease;
another health-related risk e.g. type II diabetes / atherosclerosis /
arteriosclerosis / high blood pressure;
inadequate consumption of other essential nutrients;	3 max
[7]

75.	(a)	fatty fish e.g. mackerel/tuna/sardines/herring etc.;
liver;
eggs;
fortified dairy products;	1 max
 
(b)	sunlight stimulates skin to synthesize vitamin D;
less sun exposure/insufficient vitamin D leads to skeletal
deformities/rickets;
UV radiation increases the incidence of skin cancer/melanoma;
vegans/vegetarians are more likely to lack vitamin D so
need more exposure to sunlight;	2 max
[3]

76.	(a)	63.2 ml min–1 kg–1	1
 
(b)	ventilation rate (increases more);
heart rate  × 100 = 40% and ventilation rate
 × 100 = 65%;
To award the second mark both the heart rate and the ventilation
rate are needed.	2
 
(c)	4.421 min–1 or 4.42 × 103 ml min–1 or 4424 ml min–1	1
 
(d)	no data was collected while the subject was at rest;
intervals of data collection are not regular;
only one subject has been used / data is insufficient for generalizations;
data collection was not continued beyond 13:17 to verify that the final
data reading is actually the VO2 max / no plateau phase reached;	2 max
[6]

77.	(a)	(i)	the volume of blood pumped out of the heart with each contraction	1
 
(ii)	the volume of blood pumped from the heart per time/minute	1
 
(b)	stroke volume increases which reduces the number of beats required to
maintain cardiac output	1
 
(c)	during exercise blood flow is different than at rest;
during exercise, blood flow to abdominal organs decreases;
during exercise, blood flow to skin/skeletal muscles/heart wall increases;
blood flow to the brain remains constant;	3 max
[6]

78.	(a)	anaerobic respiration;
creatine phosphate;	2
 
(b)	pros:
some natural occurring substances can vary according to body, so it would
level out all athletes;
should be able to advance sport to the maximum possible level;
allows injured athletes to recover faster;
other reasonable argument;
	cons:
(many performance-enhancing substances) have negative/unintended
side-effects;
one named side-effect of a named substance;
give some athletes unfair advantages over others;
some are unnatural;
other reasonable argument;
To award [4 max] responses require at least one pro and one con.	4 max
[6]

79.	C
[1]

80.	C
[1]

81.	A
[1]

82.	B
[1]

83.	A
[1]

84.	D
[1]

85.	D
[1]

86.	C
[1]

87.	C
[1]

88.	A
[1]

89.	C
[1]

90.	C
[1]

91.	A
[1]

92.	B
[1]

93.	D
[1]

94.	D
[1]

95.	D
[1]

96.	(a)	plasma/water;
dissolved gases / CO2 / O2;
erythrocytes / red blood cells;
leucocytes / white blood cells;
lymphocytes and phagocytes;
platelets;
hormones / named hormone(s);
amino acids / albumin / antibodies;
salts / minerals / ions other named solute in plasma apart from
glucose, urea and plasma proteins;	5 max
 
(b)	blood glucose concentration monitored by pancreas/islets/beta cells;
(more) insulin secreted in response to high blood glucose / glucose
above threshold level;
insulin stimulates cells to absorb glucose;
glucose used in cell respiration (rather than lipids);
glucose converted to glycogen;
by liver/muscle cells;
glucose converted to fatty acids / triglycerides / fat;
negative feedback process;
Accept these points if clearly made in an annotated diagram.	5 max

(c)	(filtrate formed by) ultrafiltration;
glucose / amino acids / soluble components enter Bowman’s capsule;
proteins in blood plasma but not in filtrate / proteins not filtered
out (of blood);
glucose not in urine (normally);
(selective) reabsorption (of glucose);
in the proximal convoluted tubule;
by active transport / microvilli increase the surface area;
little/no urea reabsorbed
concentration increases / urea more concentrated in urine than in
blood plasma;
water reabsorbed from filtrate;
by osmosis;
in descending limb of nephron / in proximal convoluted tubule;
salts actively transported into the medulla (from filtrate);
creating concentration gradient/hypertonic medulla;
collecting duct permeability altered depending on blood solute
concentration;	8 max
	(Plus up to [2] for quality)
[20]

97.	(a)		1
 
(b)	5% / 5.03% / 5.3% (unit required) (Accept answers in the range of
5% and 5.3%)
No indication needed of whether percentage difference is an
increase or decrease.	1
 
(c)	both birds show an increase in mass at Site 1 and a decrease at Site 2;
MW has a greater increase than HT at Site 1; {(do not accept
larger/greater change)
MW has a greater decrease than HT at Site 2; {(accept negative change)
MW has larger mass change at both sites/Site 1 and Site 2;
Do not accept answers quoting only numerical statements.	2 max
 
(d)	HT data is reliable whereas AR data is unreliable / differences not
significant /
uncertainty higher with AR;
(because) error bars/variation/range/standard deviation large for AR /
larger for AR than for HT;
(because) smaller sample of AR than of HT;
Do not accept comments about whether the data is accurate or not.	2 max

(e)	all have a higher concentration of triglyceride at Site 1 than at Site 2;
HT (and WS) highest at both sites/at Site 1;
MW lowest at Site 1 and AR lowest at Site 2;
Do not allow answers quoting only numerical statements.	2 max
 
(f)	triglyceride higher at Site 1 because more fat deposition / HT eats more;
butyrate higher at Site 2 because more fat/triglyceride utilized / HT
fasts more;	2
 
(g)	(data supports hypothesis) because mean mass at Site 1 is greater than
at Site 2 (for all birds);
because mass gained at Site 1 but mass falls (mostly) at Site 2
(over 17 years);
because triglyceride levels higher at Site 1 / butyrate levels higher
at Site 2 / more fat deposited at Site 1 / more fat utilized at
Site 2 / more fasting at Site 2;	2 max
 
(h)	advantage:
need to capture bird only once to get data / no need to mark and
catch birds again;
more informative data can be gathered; {(do not accept unqualified
“more precise”)
	disadvantage:
removal of blood is more stressful/risky for the bird than weighing;
danger of infection / spread of disease / harm to birds;
extra time/money/laboratory equipment is needed to analyse results;
could include fat/triglyceride/butyrate from previous/long-term feeding;
nutrients from food eaten at these sites may not have been absorbed yet;
Award [1] for one advantage and one disadvantage that are not the
converse of each other. Do not allow a second advantage or second
disadvantage given in the answer.	1 max
[13]

98.	(a)	occurs in cytoplasm;
hexose is phosphorylated using ATP;
hexose phosphate is split into two triose phosphates;
oxidation by removal of hydrogen;
(do not accept hydrogen ions/protons)
conversion of NAD to NADH (+H+);
net gain of two ATP / two ATP used and four ATP produced;
pyruvate produced at the end of glycolysis;
Accept glucose/fructose/6C sugar instead of hexose.
Accept 3C sugar/glyceraldehyde instead of triose.	5 max

(b)	α cells (of pancreas) produce glucagon;
glucagon promotes release of glucose/breakdown of glycogen by
liver cells;
glucagon secreted when blood glucose levels are low / raises blood
glucose levels;
β cells (of pancreas) produce insulin;
insulin promotes glucose uptake/storage of glycogen by liver/body/
muscle cells;
insulin secreted when blood glucose levels are high / lowers blood
glucose levels;
negative feedback mechanism;
Do not accept answers implying that insulin or glucagon catalyse
glucose-glycogen conversions directly.
Award [3 max] if the response suggests that the hypothalamus
has a role in regulation of blood glucose.	5 max
 
(c)	urine of diabetics contains glucose;
whereas urine of non-diabetics contains no glucose;
glomerular filtrate contains glucose / glucose filtered out;
glucose (normally) reabsorbed from filtrate/into blood;
through wall of / in the proximal convoluted tubules;
blood glucose concentration higher than normal in diabetics;
reabsorption not completed / pumps cannot reabsorb all glucose in
diabetics;
glucose in urine can be detected using test strips;
type I diabetes is lack of insulin secretion / lack of β cells;
type II diabetes is body cells not responding to insulin / not
absorbing glucose;	8 max
	(Plus up to [2] for quality)
[20]

99.	(a)	Award [1] for each of the following clearly drawn and correctly labelled.
head and midpiece/mid-section/body;
tail/flagellum; (at least four times length of the head and containing fibres)
acrosome; (shown as distinct structure near front of head)
nucleus; (occupying more than half the width or length of head)
mitochondria; (as repetitive structures inside membrane of mid piece)
centriole; (between head and midpiece)
(plasma) membrane; (shown as single line covering whole cell)
microtubules; (in 9 plus 2 array)	5 max

(b)	crossing over/chiasmata formed during prophase I of meiosis;
pairing of homologous chromosomes/synapsis;
chromatids break (at same point); (do not accept chromatids overlap)
non-sister chromatids join up/swap/exchange alleles/parts;
X-shaped structure formed / chiasmata are X-shaped structures;
chiasma formed at position where crossing over occurred;
chiasmata become visible when homologous chromosomes unpair;
chiasma holds homologous chromosomes together (until anaphase);
Accept the above points in an appropriately annotated diagram.	5 max
 
(c)	non-disjunction;
chromosomes/chromatids do not separate / go to same pole;
non-separation of (homologous) chromosomes during anaphase I;
due to incorrect spindle attachment;
non-separation of chromatids during anaphase II;
due to centromeres not dividing;
occurs during gamete/sperm/egg formation;
less common in sperm than egg formation / function of parents’ age;
Down syndrome due to extra chromosome 21;
sperm/egg/gamete receives two chromosomes of same type;
zygote/offspring with three chromosomes of same type / trisomy /
total 47 chromosomes;
Accept the above points in an appropriately annotated diagram.	8 max
	(Plus up to [2] for quality)
[20]

100.	it is a legal/medical definition of death;
some cases of coma are irreversible / some cases of coma may recover;
damage in the medulla (oblongata) is generally permanent;
doctors have to diagnose damage to decide treatment;
use tests of brain stem function to decide whether to preserve patient’s life /
without brain stem function life cannot continue;
test pupil reflex / shine light into eye;
if pupils do not constrict with light this suggests brain death;
more than one test used to diagnose brain death;
no response to pain or cranial reflexes;
legal/ethical definition needed for organ donation / long term use of life-support
machines may be inappropriate / bioethical considerations;	6 max
[6]

101.	(a)	both Po2 and Pco2 fall with increasing altitude;
above certain altitude there is little change in alveolar Po2 / Po2 remains
close to 37 mmHg over a wide range of altitudes;
Pco2 changes over the entire range of altitudes;
the Po2 is always higher than Pco2;	2 max
 
(b)	the rate of ventilation would increase;
expelling large quantity of CO2 / causing fall in blood CO2/Pco2;
rise in blood pH hampers ventilation/inhibits chemoreceptors;	2 max
 
(c)	(i)	 = 81.3% (Allow answers in the range 81–81.5%)	1
 
(ii)	low partial pressure/level of carbon dioxide in the air;
hyperventilation/high rate of ventilation;	1 max
 
(d)	high lung capacity;
larger tidal volumes;
high proportion of hemoglobin / high red blood cell count;
hemoglobin with higher affinity for oxygen;	1 max
[7]

102.	(a)	(i)	chemical messengers secreted by endocrine glands/
specialized cells directly into the blood/body fluid (and transported to
specific target cells);	1
 
(ii)	steroid hormone e.g. testosterone / peptide/protein hormone
e.g. insulin / tyrosine derivatives e.g. thyroxine;	1
 
(b)
Gastric juice	Pancreatic juice	
produced by glands in stomach wall	produced by pancreas;	
low pH / acidic	high pH / alkaline;	
contains hydrochloric acid	contains HCO3–;	
pepsinogen	trypsinogen;	
no enzymes for lipid/starch digestion	lipase/amylase;	
contains mucus	no mucus;	
both contain protease;	
	Award [1] for each pair.	3 max

(c)	cellulose / lignin;
cellulase not present / no enzymes for digesting lignin;
Accept any other reasonable substance.	2
[7]

103.	SA node is located in the wall of right atrium of heart muscle;
has characteristics of both nerve and muscle tissue;
SA node initiates each impulse;
acts as pacemaker of the heart;
no nerve impulses needed for contraction / myogenic;
connected to nerves which slow/accelerate heart rate;
impulses spread out in all directions through walls of atria;
stimulates atrial systole/contraction;
fibres in walls of atria prevent impulses from reaching ventricles;
impulses reach AV node (after atrial contraction);	6 max
[6]

104.	(a)	(i)	15.2 mg 3 hrs–1 (allow answers in the range of 15.0 to 15.4)	1
 
(ii)	1.93 NAG units 3 hrs–1 (allow answers in the range of 1.92 to 1.95)	1
 
(b)	both have a positive relationship;
values very scattered for both;
more positive correlation/steeper gradient for men than for women;
more scattered in women/greater range in hepatic activity / more scattered/
greater range in men in renal activity;	2 max
 
(c)	people with more renal damage have more cytochrome activity;
positive correlation between both increased hepatic activity and
renal damage so supports the hypothesis;
greater hepatic effect in women than in men / greater renal effect in men
than women / gender differences in effects;
very wide range of data makes it very difficult to evaluate / possibly
statistically invalid;
from this data it is impossible to establish a causal relationship / no
control group / other factors may be involved;	2 max
[6]

105.	(a)	steroid hormones enter cell whereas protein hormones bind to receptors
in membranes / steroid hormones can pass through cell membranes
while protein hormones cannot;
steroid hormones interact directly with genes/receptor proteins in
cytoplasm whereas protein hormones cause release of secondary
messenger in cell;
steroid hormones control whether or not particular enzymes or
proteins are synthesized whereas protein hormones change the
cell’s activity usually by activating or inhibiting enzymes;	2 max
 
(b)	I:	acinus cell/secretory cell/secretory vesicles;
II:	duct/lumen;	2
 
(c)	sight/smell of food initiate release of gastric juice;
before food reaches stomach, gastric juice already secreted by reflex action;
chemoreceptors/stretch receptors detect food in stomach;
impulses (from these receptors) are sent to brain, which sends impulses
to release more gastric juice;
impulses also sent to endocrine glands to release gastrin;
gastrin stimulates stomach wall to increase secretions/release acid/gastric juices/pepsinogen;
low pH of stomach (and hormones) inhibits gastrin;	4 max
[8]

106.	diagram with correct labels:
partial pressure O2/percentage O2 saturation on x-axis and percentage
saturation hemoglobin with O2 on y-axis;
exponential shape curve at lower partial pressure/concentration of CO2;
curve shifted to right (and lower) for higher partial pressure/concentration of CO2;

	hemoglobin carries (up to) four oxygen molecules;
Bohr shift promotes the release of oxygen in respiring heart muscle;
active respiration releases CO2;
partial pressure of CO2 increases;
increases acidity/lower pH/increase lactic acid;
hydrogen ions bind to hemoglobin / which decreases hemoglobin’s affinity for O2;
so O2 is released (from the oxyhemoglobin);
allosteric effect / conformational change in hemoglobin which releases
O2 more readily;
Award [4 max] if no diagram provided.	6 max
[6]

107.	D
[1]

108.	C
[1]

109.	A
[1]

110.	C
[1]

111.	A
[1]

112.	A
[1]

113.	C
[1]

114.	(a)	example of a nutrient e.g. glucose;
oxygen/O2;
carbon dioxide/CO2;
nitrogen/N2
hormones;
antibodies;
urea;	4 max
 
(b)	is myogenic;
pacemaker / SA node / OWTTE;
stimulates atria to contract;
leading to contraction of ventricles;
(autonomic) nerves can alter the pace;
(by secretion of) epinephrine/adrenaline/norepinephrine/noradrenaline
increase the pace;
(by secretion of) acetylcholine reduces the pace;
adrenal glands release epinephrine/adrenaline;
carried by blood to heart;
to increase pace;	6 max

(c)	cause: [4 max]
AIDS caused by HIV;
penetrates (T) lymphocytes;
(envelope) (glyco)protein and cell receptors involved;

number of lymphocytes reduced over years;
results in lower immunity;
other illnesses develop (as result of lower immunity);
AIDS is the observed syndrome when final stages of infection
develop / OWTTE;
	transmission: [3 max]
HIV transmitted through blood/sexual contact/body fluids/placenta/
childbirth/breastfeeding;
distribution/transmission uneven around the world;
transmission risk increased depending on society’s traditions/beliefs/
behaviour;
(rare minority of) individuals do not have cell receptors and do not
develop AIDS;
condoms/latex barriers only protection against transmission through
sexual contact;
	social implications: [3 max]
treatment expensive;
discrimination against victims;
moral obligation of wealthy countries to help poorer countries;
economic consequences / loss of wage earners etc.;
increase in the number of orphans;
comment on traditions/beliefs/behaviour; (if not already
awarded in transmission)	8 max
	(Plus up to [2] for quality)
[20]

115.	(a)	

Both needed to award the mark.	1

(b)	both increase with time;
normal mice have a greater increase in blood calcium levels than
mutant mice (after ten minutes);
normal mice have a maximum change of 1.1 µmol while mutant
mice have a maximum change of 0.6 µmol;
mutant mice show gradual increase while normal mice show
rapid increase followed by a plateau;	2 max
 
(c)	mice with low calcium diets have a greater increase in blood
calcium levels (after calcium administration) because their body
absorbs more calcium;
if they have had a high calcium diet they do not need to absorb
so much calcium / vice versa;
probably receptors are all occupied/inhibited / less receptors;	2 max
 
(d)	hypothesis supported as blood calcium levels increased in
mutant mice after intake of calcium (graph A);
but less than in normal mice / perhaps not enough to cure
disease/rickets;
administering vitamin D also shows an increase in blood
calcium levels (graph A);
but no good administering vitamin D as the receptor is defective;
in a high calcium diet, less absorption occurs (graph B), so
might not be the solution;
should have tested mutant mice with different diets;	2 max
[7]

116.	(a)	(i)	causes sensation of being full/having eaten too much (when receives
messages);
stimulated by hormones (insulin, CCK) produced by pancreas/small
intestine after eating;
stretch receptors in stomach after eating;
hormones (leptin) produced by adipose tissue in response to fat
storage;
send message to appetite control centre in brain;	3 max
 
(ii)	BMI of 16 (kg m–2) is underweight so there is a health risk;
underweight so may be taking in insufficient nutrients;	1 max

(b)
Component	Human milk	Artificial milk	
sugar	lactose	lactose / glucose;	
protein	human whey / casein / albumin / human milk protein;	soya protein	
antibodies	present	absent/not present;	
		3
[7]

117.	food miles are a measure of how far food is transported to consumption site;
high food miles cause pollution/greenhouse gas emissions/increased fuel
consumption for transport;
traffic congestion / road damage;
allows continuity of supply / increase in choice;
maintenance of subsistence crop production (in undeveloped/developing
countries);
high food miles do not support local communities;
food may not be as fresh as local produce / use more preservatives;	4 max
[4]

118.	(a)	positive/direct correlation / as mitochondrial concentration increases so
does HAD activity	1
 
(b)	fur seal has greater mitochondrial concentration / vice versa;
fur seal has greater HAD activity / vice versa;
lowest value of HAD for fur seal equal to/slightly above highest sea lion
value/ no overlap of data points;	2 max
 
(c)	swimming muscle has a greater mitochondrial concentration than
non-swimming muscle;
the range in HAD activity is similar in both / non-swimming has slightly
larger range;
mitochondrial concentration overlaps in the middle range of values / low
mitochondrial concentration only in non-swimming muscle / highest
mitochondrial concentration only in swimming muscle;	2

(d)	more mitochondria means more aerobic respiration;
more mitochondria in swimming muscles;
products of fatty acid oxidation could be used in respiration
(so hypothesis could be supported);
increase in HAD activity would mean an increase in fatty acid
oxidation;
little/no increase in HAD activity in swimming muscles (so
hypothesis not supported);
during diving low oxygen/hypoxic conditions so high HAD activity/
mitochondrial concentration allows aerobic metabolism to continue;	3 max
[8]

119.	(a)	I.	thick filament / myosin;
II.	Z line;
III.	A/dark band;	3
 
(b)	vital capacity may increase slightly/appears to be unaffected by training;
Do not award the mark for increase that is unqualified.	1
[4]

120.	(a)	moderate-intensity exercise stimulates development (in size) of slow muscle
fibres whilst high-intensity exercise stimulates development (in size) of fast
muscle fibres;
both decrease heart rate at rest;	2
 
(b)	benefits:
more red blood cells after transfusion so more transport of oxygen
by hemoglobin;
enhances endurance; OWTTE
	risks:
foreign blood could cause rejection / own blood banks to avoid rejection/
disease transmission;
excess of red blood cells causes clots;
bigger volume of blood increases blood pressure;
unethical/unfair advantage to athlete results in banning/disqualification;
To award [4 max] at least one risk and one benefit must be addressed.	4 max
[6]

121.	(a)	I.	dorsal root ganglion;
II.	grey matter;
III.	motor neuron;	3

(b)	decision-making involves synapses / pre and postsynaptic neurons are
required;
some presynaptic neurons are excitatory and some are inhibitory;
interaction between excitatory and inhibitory presynaptic neurons with
the postsynaptic neuron;
excitatory and inhibitory produce different neurotransmitters;
the impulses from presynaptic neurons are generally summative;
decision-making is a (mental) process leading to the selection of
alternatives/strategies / frontal cortex/lobes are brain regions
involved in decision-making processes;	3 max
[6]

122.	C
[1]

123.	C
[1]

124.	D
[1]

125.	C
[1]

126.	B
[1]

127.	D
[1]

128.	D
[1]

129.	C
[1]

130.	A
[1]

131.	(a)	the acquisition of antibodies from another organism	1
 
(b)	
Accept any other valid examples.	1
 
(c)	an organism/virus that causes a disease	1
 
(d)	antibiotics block/inhibit specific metabolic pathways/
cell functions found in bacteria;
	Accept specific examples of inhibition such as cell protein synthesis
cell wall formation
	viruses must use host/eukaryotic cell metabolism / viruses do not
have their own metabolic pathways;
host/eukaryotic cell metabolism/pathways not blocked/inhibited by
antibiotics;	2 max
[5]

132.	(a)	Award [1] for each of the following clearly drawn and correctly labelled.
head and midpiece/mid-section/body;
tail/flagellum; (at least four times length of the head and containing fibres)
acrosome; (shown as distinct structure near front of head)
nucleus; (occupying more than half the width or length of head)
mitochondria; (as repetitive structures inside membrane of mid piece)
centriole; (between head and midpiece)
(plasma) membrane; (shown as single line covering whole cell)
microtubules; (in 9 plus 2 array)	4 max

(b)	FSH promotes development of a new follicle;
also leads to the production of estrogen;
estrogen brings about repair and growth of uterine lining;
estrogen causes negative feedback of FSH;
estrogen brings about LH production;
LH stimulates follicle growth;
LH triggers ovulation;
estrogen contributes to the proliferative phase of the uterine cycle /
triggers LH surge;
progesterone contributes to the secretory phase of the uterine cycle/
maintains uterus lining;
lowered level of progesterone (due to degeneration of corpus luteum)
leads to menstruation;	6 max
 
(c)	cause: [4 max]
AIDS caused by HIV;
penetrates (T) lymphocytes;
(envelope) (glyco)protein and cell receptors involved;

number of lymphocytes reduced over years;
results in lower immunity;
other illnesses develop (as result of lower immunity);
AIDS is the observed syndrome when final stages of infection
develop / OWTTE;
	transmission: [3 max]
HIV transmitted through blood/sexual contact/body fluids/placenta/
childbirth/breastfeeding;
distribution/transmission uneven around the world;
transmission risk increased depending on society’s traditions/beliefs/
behaviour;
(rare minority of) individuals do not have cell receptors and do not
develop AIDS;
condoms/latex barriers only protection against transmission through
sexual contact;
	social implications: [3 max]
treatment expensive;
discrimination against victims;
moral obligation of wealthy countries to help poorer countries;
economic consequences / loss of wage earners etc.;
increase in the number of orphans;
comment on traditions/beliefs/behaviour;
(if not already awarded in transmission)	8 max
[18]

133.	(a)	for both men and women a decrease is seen at the lowest alcohol intake
followed by an increase;
the level of CRP is higher in women than in men over the range of
alcohol consumption / as the intake increases the difference between
men and women increases, the CRP increase being greater in women;	1 max
 
(b)	drinking small amounts of alcohol seems to reduce the level of all
markers / drinking none and/or high amounts of alcohol has higher
levels of markers than moderate amount;
the effect of small amounts of alcohol is less in women than in men /
the effect of large amounts of alcohol is greater in women than in men /
women should consume less than men;
other effects of alcohol consumption are not measured;
other factors increasing risk of CVD are not measured;
the type of alcohol is not stated / the active factor in the drink is not seen;	3 max
 
(c)	CRP shows the decrease in risk for low amounts of alcohol then increases
above the baseline for higher amounts	1
 
(d)	high blood pressure damages endothelial wall;
WBC/macrophages build up cholesterol;
plaque hardens arterial wall / blocks lumen / artery blocked by
depositions in wall;
wall rough;
clots form;	2 max
[7]

134.	(a)	I.	hepatic cells / hepatocytes / liver cells / liver tissue;
II.	hepatic vein / blood cells;
III.	sinusoids;	3
 
(b)	storage of nutrients;
detoxification of poisons;
breakdown of hemoglobin;
production of bile pigments;
synthesis of plasma proteins;
synthesis of cholesterol;	2 max
 
(c)	Award [1] for two of the following.
cellulose / lignin / bile pigments / bacteria / intestinal cells
Do not accept fibre.	1

(d)	insulin / glucagon / prolactin / somatotrophin
Award other suitable examples.	1
[7]

135.	adult hemoglobin: [2 max]
rapid saturation of oxygen in the lungs;
rapid dissociation of oxygen as the oxygen concentration decreases;
oxygen released in the tissues where needed;
	fetal hemoglobin: [2 max]
fetal hemoglobin curve to the left of adult hemoglobin;
higher affinity for oxygen than adult hemoglobin;
oxygen moves from adult hemoglobin to fetal hemoglobin;
	myoglobin: [2 max]
myoglobin to the left of fetal hemoglobin;
higher affinity for oxygen than adult hemoglobin;
only releases oxygen at very low oxygen concentrations/in tissues;
oxygen reserve;	6 max
[6]

136.	C
[1]

137.	C
[1]

138.	D
[1]

139.	A
[1]

140.	D
[1]

141.	B
[1]

142.	A
[1]

143.	C
[1]

144.	A
[1]

145.	B
[1]

146.	A
[1]

147.	C
[1]

148.	Must be genuine differences not descriptions of one type of diabetes followed by description of other type of diabetes. If two totally separate descriptions/no paired statements are written, award [2 max].

Type I diabetes	Type II diabetes	
early-onset/childhood diabetes / usually develops in those under 20 years old
Do not accept present at birth.	adult-onset diabetes / usually occurs in those over 40 years old;	
inability to produce sufficient quantities of insulin	inability to respond to insulin (due to insufficient receptors on target cells);	
target cells remain sensitive to insulin	target cells less sensitive to insulin;	
genetic predisposition/virus/autoimmune disorder / destruction of (pancreatic) beta cells involved	is linked with dietary/lifestyle factors / increased fatty acids in blood;	
requires daily injections of insulin / beta cell transplant	controlled by diet/exercise/weight loss/medication but not insulin injections;	
		3 max
[3]

149.	(a)	Award [1] for each of the following clearly drawn and correctly labelled.
phospholipid bilayer —double row of opposing phospholipids, tails to inside;
phospholipid —with head and two tails;
hydrophilic/phosphate/polar (heads) and hydrophobic/hydrocarbon/fatty
acid/non-polar (tails) labelled;
integral protein — embedded in the phospholipid bilayer;
protein channel — integral protein showing clear channel/pore;
peripheral protein—on the surface;
glycoprotein—with carbohydrate attached on one side;
cholesterol—shown embedded in bilayer;	5 max
 
(b)	vesicles formed from rER transport proteins to Golgi apparatus;
these vesicles fuse with membranes of Golgi apparatus;
proteins are processed as they move through Golgi apparatus;
(transport) vesicles bud off/leave Golgi apparatus;
vesicles move through cytoplasm;
(vesicles) fuse with plasma membrane;
contents released to outside of cell / exocytosis;
cells use vesicles to secrete substances such as hormones/digestive
enzymes/other appropriate example;
vesicles may contain cell products other than proteins;
Credit drawings which fully explain the points above.	6 max

(c)	To achieve [1] answer must name the structure and relate it to its function.
the villus has a large surface area to volume ratio;
microvilli increase surface area for absorption;
thin surface (epithelial) layer so products of digestion can pass easily through;
channel proteins located in plasma membrane used for facilitated diffusion;
network of capillaries inside each villus (so only short distance) for movement
of absorbed products;
capillaries transport absorbed nutrients/sugars and amino acids away from
small intestine;
blood flow in capillaries maintains concentration gradient;
central lymph vessel/lacteal to transport absorbed fats/fatty acids away from
small intestine;
large number of mitochondria provide ATP needed for active transport;
protein pumps in membrane (of microvilli) carry out active transport;
pinocytosis occurs at surface (epithelial) layer;
Accept any of the points above shown in a drawing.	7 max
	(Plus up to [2] for quality)
[20]

150.	(a)	Award [1] for each structure clearly drawn and correctly labelled.
Schematic diagrams are acceptable.
right and left ventricles—not connected shown larger than atria;
right and left atrium—not connected, thinner walls than ventricles;
right ventricle has thinner walls than left ventricle / vice versa;
atrio-ventricular valves / tricuspid and bicuspid valves — shown between
atria and ventricles;
aorta and pulmonary artery—shown leaving the appropriate ventricle
with semilunar valves shown;
pulmonary vein and vena cava — shown entering appropriate atrium;
Vessels must join unambiguously to correct chamber.	4 max
 
(b)	arteries carry blood under high pressure;
they have a thicker elastic wall/narrower lumen;
they have muscles that control pressure / help move the blood;
veins carry blood under lower pressure;
they have thin walls with less elastic tissue/muscle/wider lumen;
have valves to prevent back flow;
capillaries have walls which are one cell thick;
to allow easy diffusion across their wall / ultrafiltration;
(some) capillaries have pores/clefts;
Award [5 max] if capillaries are not referred to.	6 max

(c)	external intercostal muscles contract;
internal intercostal muscles relax;
pulling the rib cage upwards;
diaphragm contracts and flattens;
increase in volume of thoracic cavity;
this reduces pressure;
so air enters the lungs;
internal intercostal muscles contract / external intercostal muscles relax;
diaphragm relaxes;
abdominal muscles/organs/liver push diaphragm upwards;
decrease in volume of thoracic cavity;
increases the pressure;
so air leaves the lungs;
Award any of the above points if clearly drawn in a diagram.	8 max
	(Plus up to [2] for quality)
[20]

151.	(a)	Award [1] for each structure clearly drawn and correctly labelled.
ovary—shown adjacent to but not joined to oviduct/fallopian tube;
oviduct/fallopian tube — shown as a tube leading into a uterus;
uterus—shown with a thicker wall than oviduct/fallopian tube;
vagina—shown leading from the uterus, connected to the cervix;
cervix — shown as a constriction between the vagina and uterus;
endometrium—shown as inner lining of uterus;	4 max
 
(b)	populations produce more offspring than can survive;
individuals show variation;
limited resources;
create a struggle for survival/competition;
survival of the fittest / some are better suited to the environment
and survive;
variation/characteristic must be heritable;
best fitted individuals survive to reproduce;
advantageous variation/characteristic/allele passed on;
over time advantageous variation/characteristic/allele increases in
the population;	6 max

(c)	altering a base (in DNA) is a (point) mutation;
only has an effect if base is in a gene;
when mRNA is produced by transcription one mRNA base is different;
one codon in mRNA is different;
one amino acid is different in the polypeptide;
polypeptide produced by translation of mRNA;
some base changes do not change the amino acid coded for;
structure of polypeptide /protein may be altered;
usually the polypeptide/protein does not function as well;
	example given:
disease: sickle cell anemia;
mutation: GAG to GTG;
consequence in translation: glutamic acid to valine;
consequence for protein: hemoglobin altered so sickle cell formed;
consequence for individual: less oxygen can be carried;	8 max
	(Plus up to [2] for quality)
[20]

152.	(a)	monounsaturated fatty acids and carbohydrates (both required)	1
 
(b)	80 (%) (units not required)
Allow answers in the range of 80.00 to 80.20%.	1
 
(c)	

cholesterol increases the most in monounsaturated fatty acids (in mg dl–1);
VLDL has highest percentage increase in monounsaturated fatty acids;	2 max
 
(d)	less cholesterol/VLDL/LDL means lower chance of coronary heart
disease/CHD;
accumulation of fats in arteries leads to atherosclerosis/clots/coronary
heart disease/CHD;
hypothesis seems to be supported as triglycerides/cholesterol/VLDL/LDL
decrease;
hypothesis seems to be supported as the ratio of the LDL:HDL is lower;
hypothesis seems not to be supported as HDL remains about the same;	3 max
[7]

153.	(a)	dairy products / (oily) fish / egg yolk / liver etc.	1

(b)	appetite controlled by hormones;
produced in pancreas / small intestine / adipose tissue;
pass message to control centre in brain/hypothalamus;
sensation of satiety / OWTTE;
stomach has stretch receptors which send message to brain;	3 max
[4]

154.	(a)	(i)	body becomes resistant/not responsive to insulin;
pancreas does not produce enough insulin;
dietary factors / genetic predisposition;
lack of exercise;	1 max
 
(ii)	high glucose content in blood/hyperglycemia;
thirst/frequent urination;
slow-healing sores;
tiredness;
red/swollen gums;
blurred vision/blindness;
kidney/back pain;
nerve damage;
glucose in urine;
erectile dysfunction;	2 max
 
(b)	PKU caused by mutation in gene;
phenylalanine builds up in bloodstream;
so must not be contained in diet / diet low in phenylalanine / few
proteins eaten;
diet should include fruit, grain, vegetables and special formula milk;
diet must be undertaken very early in life;
otherwise brain damage/mental retardation;
tremors / seizures / eczema / skin rashes;	4 max
[7]

155.	(a)	3 m mol l–1 (allow answers in the range of 2.8 m mol l–1 to 3.2 m mol l–1)	1
 
(b)	increases arterial lactate concentration	1

(c)	altitude and hypoxia increase arterial lactate concentration due to more
anaerobic respiration;
altitude has a greater effect than oxygen concentration;
the values of hypoxia are greater than normoxia at 0 m (sea level) but
the same at high altitude;
altitude/hypoxia causes less oxygen saturation of hemoglobin so less
oxygen available in tissues;
altitude/hypoxia causes less oxygen for aerobic respiration;	3 max
 
(d)	passed to liver;
turned into pyruvate;
used in aerobic respiration;
converted to glucose;	2 max
[7]

156.	(a)	I.	Z line;
II.	actin (filaments);	2
 
(b)	(i)
slow muscle fibre (tonic)	fast muscle fibre (twitch)	
contract slowly	contract rapidly;	
resist fatigue	fatigue easily;	
high myoglobin	low myoglobin;	
aerobic metabolism	anaerobic metabolism;	
very good blood supply	moderate blood supply;	
high stamina	low stamina;	
more mitrochondria	less mitrochondria;	
	Award [1] per correct row.	2 max
 
(ii)	warm up involves gentle exercise before exercise;
warm muscles/joints are less likely to be strained/more supple;
increases blood flow/oxygen to muscles;
but there is limited scientific proof;
some people do not suffer ill effects from not warming up;	3 max
[7]

157.	(a)	maximum volume of air exhaled after deep inhalation	1

(b)	benefits:
EPO induces production of red blood cells;
more red blood cells so more oxygen in muscles;
gives advantage over athletes that do not use it / increased performance;
	risks:
but too many red blood cells can produce damage in capillaries/heart
failure/chronic mountain sickness/increased blood clotting/increased
risk of stroke;
limited information on long-term effects;
exclusion/banning from competitions;
Award [2 max] if only benefits or risks are addressed.	3 max
[4]

158.	C
[1]

159.	C
[1]

160.	C
[1]

161.	B
[1]

162.	B
[1]

163.	B
[1]

164.	C
[1]

165.	A
[1]

166.	C
[1]

167.	A
[1]

168.	A
[1]

169.	D
[1]

170.	D
[1]

171.	C
[1]

172.	B
[1]

173.	(a)	non-disjunction (can cause Down syndrome);
occurs when pair of homologous chromosomes fails to separate
during meiosis;
one gamete/daughter cell receives two chromosomes / diagram
showing this;
occurs in anaphase I/II of meiosis;
fertilization involving this gamete leads to change in chromosome
number/47 chromosomes;
most common form of Down is trisomy 21/extra chromosome 21;
increase risk of Down syndrome with increased age of mother;	4 max

(b)	oogenesis is process by which female gametes/eggs are produced;
begins during fetal development;
oogonia/large number of cells formed by mitosis;
oogonia/cells enlarge/undergo cell growth/become primary oocytes;
begin first meiotic division but stop in Prophase I;
until puberty;
(at puberty) some follicles develop each month in response to FSH;
(primary oocyte) completes first meiotic division;
forms two cells of different/unequal sizes / unequal distribution
of cytoplasm;
(creating a) polar body;
polar body eventually degenerates;
larger cell/secondary oocyte proceeds to meiosis II;
stops at prophase II;
meiosis II completed if cell is fertilized;
ovum and second polar body formed;	8 max
 
(c)	To award full marks, discussion must contain both pro and con
considerations.
	pros/positive considerations: [3 max]
chance for infertile couples to have children;
decision to have children is clearly a conscious one due to difficulty of
becoming pregnant;
genetic screening of embryos could decrease suffering from genetic diseases;
spare embryos can safely be stored for future pregnancies/used for
stem cell research;
	cons/negative considerations: [3 max]
IVF is expensive and might not be equally accessible;
success rate is low therefore it is stressful for the couple;
it is not natural/cultural/religious objections;
could lead to eugenics/gender choice;
could lead to (unwanted) multiple pregnancies with associated risks;
production and storage of unused embryos / associated legal issues /
extra embryos may be used for (stem cell) research;
inherited forms of infertility might be passed on to children;
Accept any other reasonable answers.	6 max
	(Plus up to [2] for quality)
[20]

174.	(a)	antibiotic resistance can be inherited;
alleles for resistance can be passed from one cell to another by exchange
of plasmids/conjugation;
some varieties are more resistant than others;
bacteria reproduce very rapidly and have high mutation rate;
evolution can occur rapidly;
increased exposure to antibiotics is the environmental change that
selects for resistant varieties;
for example, in hospitals / animal feed / inappropriate prescriptions /
not finishing prescriptions;
bacteria without resistance die / resistant bacteria survive and pass on
genes to next generation;
results in change in genetic makeup of population;	5 max
 
(b)	immunity is the ability of an organism to resist infection;
due to presence of (specific) antibodies;
immunity can be active or passive;
passive due to receiving antibodies from external sources/across
placenta/from breast milk/injection;
active results from facing an infection directly/through vaccination;
pathogen/foreign cell invades body;
leads to clonal selection/formation of B memory cells;
B-cells produce specific antibodies;
if same pathogen enters body again memory cells activated/stimulated
to divide;
antibodies produced faster and in greater amounts;	6 max
 
(c)	Benefits: [4 max]
immunity results
can limit pandemics/epidemics/spread of (infectious) diseases;
diseases can be eradicated/smallpox eliminated;
reduces mortality/deaths due to disease;
can protect vulnerable groups/young/old/with other conditions;
decrease crippling effects of diseases (such as polio);
decreased health care costs;
	Dangers: [4 max]
may produce (mild) symptoms of the disease;
human error in preparation/storage/administration of vaccine;
individual may react badly to vaccine / defective immune system /
hypersensitive/allergic reaction;
immunity may not be life-long/booster required;
possible toxic effects of mercury-based preservatives/thimerosal;	7 max
	(Plus up to [2] for quality)
[20]

175.	(a)	Award [1] for each structure clearly drawn and correctly labelled.
ovary — shown adjacent to but not joined to oviduct/fallopian tube;
oviduct/fallopian tube — shown as a tube leading into a uterus;
uterus —shown with a thicker wall than oviduct/fallopian tube;
vagina — shown leading from the uterus, connected to the cervix;
cervix —shown as a constriction between the vagina and uterus;
endometrium — shown as inner lining of uterus;	4 max
 
(b)	follicles secrete estrogen / FSH stimulates secretion of estrogen;
(rapid) increase in estrogen stimulates FSH/LH production;
estrogen also stimulates repair/thickening of endometrium/uterus lining;
LH causes follicle to produce less estrogen/more progesterone;
corpus luteum secretes more estrogen/progesterone;
progesterone maintains/stimulates thickening of endometrium/uterus lining;
estrogen/progesterone inhibit FSH/LH secretion;
estrogen/progesterone levels fall after day 21–24 if no embryo/fertilization;
lower concentration of estrogen/progesterone allows disintegration of endometrium/uterus lining / menstruation occurs;
Award [4 max] if only one hormone is explained.	6 max
 
(c)	transfer of foods/nutrients/glucose from mother to fetus;
fetal gas exchange/transfer of oxygen from mother to fetus;
transfer of excretory products/CO2 from fetus to mother;
transfer of antibodies/hormones from mother to fetus;
secretion of estrogen/progesterone;
from approximately 12 weeks / when ovary/corpus luteum stops secretion;
disc shaped structure;
connected to the fetus by an umbilical cord;
embryonic tissue invades/grows into the uterine wall;
placental villi increase the surface area (for exchange);
fetal capillaries in placenta/placental villi;
inter-villous spaces/sinuses through which mother’s blood flows;
small distance between fetal and mother’s blood/narrow placental barrier;
Allow reference to embryo instead of fetus throughout.	8 max
	(Plus up to [2] for quality)
[20]

176.	(a)	Award [1] for each structure clearly drawn and correctly labelled.
Schematic diagrams are acceptable.
right and left ventricles — not connected shown larger than atria;
right and left atrium — not connected, thinner walls than ventricles;
right ventricle has thinner walls than left ventricle / vice versa;
atrio-ventricular valves / tricuspid and bicuspid valves — shown between
atria and ventricles;
aorta and pulmonary artery — shown leaving the appropriate ventricle
with semilunar valves shown;
pulmonary vein and vena cava — shown entering appropriate atrium;
Vessels must join unambiguously to correct chamber.	4 max
 
(b)	cells/tissue is damaged/cut/bruised;
damaged cells/platelets release clotting factors;
(clotting factors cause the) production of thrombin;
blood plasma contains soluble fibrinogen;
fibrinogen converted into fibrin;
by thrombin;
forms a net of fibres trapping blood cells;
forming a clot / prevents blood loss / entry of bacteria/pathogens;
cascade of reactions/series of stages prevent accidental clotting/
speed up clotting;	6 max
 
(c)	benefits: [6 max]
immunity results
can limit pandemics/epidemics/spread of (infectious) diseases;
diseases can be eradicated/smallpox eliminated;
reduces mortality/deaths due to disease;
can protect vulnerable groups/young/old/with other conditions;
decreases crippling effects of diseases (such as polio);
decreased health care costs;
	risks: [6 max]
may produce (mild) symptoms of the disease;
human error in preparation/storage/administration of vaccine;
individual may react badly to vaccine / defective immune system /
hypersensitive/allergic reaction;
immunity may not be life-long / booster required;
possible toxic effects of mercury-based preservatives/thimerosal;	8 max
	(Plus up to [2] for quality)
[20]

177.	(a)	(i)	 × 100 = 500%	1
 
(ii)	increased anaerobic respiration at high altitude/4300 m due to low
partial pressure of oxygen	1
 
(b)	glucose concentration starts to fall after the start of the exercise then
levels off/decrease slows down / glucose drops from 5.35 mM to 4.65 mM;
lactate concentration increases then levels off/then decreases / lactate
increase from 0.4 mM to1.9 mM;
changes in lactate are the inverse of those in glucose;	2 max

(c)	initial glucose concentration was lower at high altitude / glucose
concentration increases only slightly/stays level (during exercise)
at high altitude;
lactate concentration rises more sharply at high altitude / but initial
concentration of lactate was similar;
less efficient use of glucose under anaerobic conditions / sharper
increase in lactate concentration caused by increase in anaerobic
metabolism;	3
[7]

178.	(a)	active transport: against concentration gradient and requires ATP and
protein pumps/transport proteins;
facilitated diffusion: along concentration gradient, is passive/no ATP
required and requires carrier/transport proteins;
simple diffusion: passive/no ATP required and along concentration
gradient and through protein channels;
endocytosis: invagination of the cell membrane making a vesicle;	2 max
 
(b)	Two of the following needed for [1].
cellulose/fibres
lignin
bile pigment
bacteria
intestinal cells	1 max
[3]

179.	(a)	Named factors correctly outlined.
genetic — some people predisposed for high cholesterol levels /
high blood pressure;
age —older people greater risk / less elasticity in arteries;
sex —males at greater risk of heart disease than (pre-menopausal)
women as estrogen protects against heart disease;
smoking —constricts blood vessels / increases blood pressure/
heart-rate / decreases oxygenation of heart muscle;
diet — increased fat/cholesterol/LDL in blood leads to plaque
formation in arteries;
exercise — helps reduce high blood pressure / exercise reduces
the rate of fatty deposits building up in the inner lining of
arteries/thickens the heart muscle walls so they pump blood more efficiently;
obesity — increase in blood pressure / leads to plaque formation
in arteries;
Accept any other factor with brief account e.g. diabetes,
atherosclerosis.
Do not award a mark for the name of a factor and simply that
it leads to CHD.	5 max

(b)	H. pylori is a bacterium which causes gastritis;
stomach ulcers are open sores in the stomach wall;
prolonged presence of ulcers may lead to the formation of tumours;
cancer of the stomach is a malignant tumour in the stomach wall;
about 80% of gastric ulcers are caused by H. pylori;
H. pylori survives in the stomach mucosa;
producing urease;
which neutralizes gastric acid;
colonization by H. pylori opens up/weakens the (protective)
(mucosal/mucus) lining;
for digestive attack by gastric acid/HCl causing ulcers;
linking H. pylori to stomach ulcers was a paradigm shift in medicine;
cause was previously thought to be stress/lifestyle/diet;
H. pylori now thought to be primary cause / now treated as
infectious disease;	5 max
[10]

180.	(a)	0 m/at sea level/in Copenhagen and hypoxia	1
 
(b)	correct calculation;
decreases by 28.57% (allow 28.6%)	2
 
(c)	at altitude 5260 m and normoxia there is greatest power output
per kilogram of body mass;
altitude has little effect as the values for 0 m normoxia and
5260 m normoxia are very similar / normoxia is the (more)
important factor (at both altitudes);
O2 levels are significant as values for 0 m hypoxia and 5260 m
hypoxia are very similar/much lower than for normoxia;
O2 levels are more significant than altitude in allowing for
greater power out (per kg body mass);	2 max
 
(d)	more hemoglobin permits the carrying of more O2 / greater
carrying capacity of O2 / OWTTE;
body acclimatizes to hypoxia/lower O2 partial pressure/concentration;	1 max

(e)	lung capacity can increase so that O2 intake becomes more efficient
per breath;
heart rate can increase so that the available O2 is circulated around
the body more quickly to counter the reduced O2 availability;
increased number of red blood cells allow greater carrying capacity
(greater amount of hemoglobin);
muscles produce more myoglobin to bind more O2;
Accept any other valid adaptations.	2 max
[8]

181.	(a)	steroid hormones enter cell while protein hormones bind to specific
membrane receptors / steroid hormones can pass through cell
membranes while protein hormones cannot;
steroid hormones interact directly with genes/receptor proteins in
the cytoplasm while protein hormones achieve their effects by
causing the release of secondary messenger into the cell;	2
 
(b)	causes increased acid secretion / produces toxins / forms pores in
epithelial cell membrane / produces urease which produces ammonia
(which is toxic) / resides in gastric mucous protected from immune
system reactions but cause inflammation and increase acid
production / destroys mucus lining exposure to acid/causing inflammation	1
[3]

182.	(a)	Award [1] for a factor and [1] for its effect.
	Accept any two of the following factors with its associated effect:
e.g.: genetic predisposition / age / being male / obesity / eating too
much saturated fat and cholesterol / lack of exercise / smoking /
diabetes (melitus) / hypertension / stress.
Accept converse statements of factors decreasing risk.
	e.g.	factor:	genetic predisposition;
effect:	some synthesise more cholesterol/LDL than others;
	e.g.	factor:	being male;
effect:	women before menopause appear to be protected by
	higher blood estrogen levels which men do not have;
	e.g.:	factor:	obesity;
effect:	excess weight raises blood pressure/blood cholesterol/
	triglyceride levels / lowers HDL/good cholesterol levels;	4

(b)	can cause inflammation/fatty liver/cirrhosis of the liver from alcohol abuse;
usually from prolonged/excessive drinking / OWTTE;
products of alcohol metabolism toxic to cells / alcohol consumption
reduces antioxidant activity;
replacement of healthy liver cells with fibrous/scar tissue;
blocks blood flow through liver / loss of functional liver cells /
blocks normal metabolic carbohydrates/fats/proteins;
decreased ability to remove toxins (through bile)/bacteria / production
of bile and blood proteins;
nutritional deprivation / susceptible to infection/hepatic viruses;	5 max
[9]

183.	D
[1]

184.	D
[1]

185.	C
[1]

186.	D
[1]

187.	A
[1]

188.	C
[1]

189.	(a)	stomach	1
 
(b)	enzymes speed up the digestive processes;
(chemical) break down of food/food particles/large molecules;
make soluble products/molecules small enough to be absorbed;	2 max
 
(c)	to (re)absorb water/vitamins(s) (e.g. K and B12) / temporary storage of feces	1
 
(d)	N.B. for each marking point, function should accompany structure.
shape of villus has large surface area to improve absorption / microvilli
increase surface area to improve absorption;
thin walls/epithelium to allow fast diffusion;
capillaries/rich blood supply (nearby) to absorb digested food products/
maintain concentration gradient;
lacteal in villus to absorb fatty acids/fats (and carry them away from
small intestine);
protein pumps in membrane to carry on active transport / channel
proteins in membrane to facilitate diffusion;
large number of mitochondria provide ATP for active transport;	3 max
[7]

190.	(a)	letter U marked/labelled on uterus
Accept in lumen or on wall.	1
 
(b)	formation of the corpus luteum	1
 
(c)	allows characteristics from both parents to appear in offspring;
crossing over (during prophase 1) changes chromosome composition;
produces gametes which are all different;
random chance of which sperm fertilizes ovum;
greater variation (resulting from sexual reproduction) favours survival
of species through natural selection;
Accept independent assortment during meiosis from AHL.	3 max
[5]

191.	(a)	Award [1] for each structure clearly drawn and correctly labelled.
trachea;
bronchi;
bronchioles;
lungs;
alveoli — shown enlarged as inset;
diaphragm;
intercostal muscles;
abdominal (wall) muscles;
Award [3 max] for diagrams that do not show correct connections
or proportions.	4 max

(b)	anaerobic (cell) respiration in the absence of oxygen;
glycolysis / breakdown of glucose molecules;
leads to the production of pyruvate;
also known as fermentation;
production of small yield/two ATP (molecules per molecule of
glucose respired);
produces ethanol;
produces carbon dioxide;
occurs in cytoplasm;
example of anaerobic respiration in plants (e.g. waterlogged roots);	5 max
 
(c)	maintaining the internal environment constant/between narrow limits;
example (other than blood sugar) of blood pH / oxygen and carbon dioxide
concentrations / body temperature / water balance;
involves negative feedback;
where a variation from the normal (blood sugar level) triggers the
correction mechanisms;
controlled by both nervous and endocrine systems;
blood sugar above normal stimulates insulin release;
insulin secreted by β cells in the (islets of the) pancreas;
insulin lowers blood sugar;
by converting to glycogen/fat / increased respiration;
blood sugar below normal stimulates glucagon release;
glucagon secreted by α cells in the (islets of the) pancreas;
glycogen converted to glucose;
causes increased level of glucose in the blood;	9 max
	(Plus up to [2] for quality)
[20]

192.	(a)	mean zinc content higher in control group;
control group more variable;
overlap between two groups / highest of anorexia nervosa group equals
mean of control group;	2 max
 
(b)	(data suggest this is) probable / could be symptom;
other conditions could lead to low zinc;
6 µg g–1 is within the lower range of “normal”;	2 max
 
(c)	zinc supplementation is necessary for insufficient dietary intake /
improvement in below normal intake would be resolved;
improved appetite may result;
low zinc may be effect not cause of anorexia nervosa / other
causes of anorexia;	2 max

(d)	minerals are inorganic while vitamins are organic;
minerals tend to be in ionic elemental form/small molecules while
vitamins tend to be larger molecules;	1 max
 
(e)	(below a BMI of) 18.5 kg m–2 (units needed)	1
[8]

193.	(a)	lack of blood plasma proteins;
subsequent tissue fluid retention;
swelling of abdomen;
retarded physical and mental development of children;
muscle wastage;	1 max
 
(b)	sedentary lifestyle/occupations / lack of exercise;
diets high in processed contents / low in complex carbohydrates;
diets high in fat;
availability of inexpensive food / large portion sizes;	3 max
 
(c)	advantages:
less consumption of aviation fuel / less fossil fuel consumption
per food unit;
reduced pollution/road congestion;
food will be fresher;
	disadvantages:
reduction in choice / less access to exotic foods;
reduction in access to foods out of season;
reduced international trade (with developing countries);
might be more expensive (short-term);
Award [2 max] for responses that address advantages or
disadvantages only.	3 max
[7]

194.	cis (isomers) or trans (isomers);
saturated or unsaturated;
monounsaturated or polyunsaturated;
location of the double bond;
can be short chain or long chain;	3 max
[3]

195.	(a)	both rates increase with time;
rate of release of H+ always higher;
rate of release of H+ increases faster than that of lactate;	2 max
 
(b)	lactate production indicates anaerobic cell respiration;
a correlation between lactate and H+ / some support for hypothesis;
expect 1H+ to 1 lactate / ratio of H+ to lactate higher than 1:1;
H+ cannot account for all the acid / there must be another source of H+;	2 max
 
(c)	both will continue to rise;
because of the acid, they cannot both continue to rise indefinitely /
will level off;
because of muscle fatigue, they cannot both continue to rise
indefinitely / will level-off;	2 max
[6]

196.	(a)	Award [1] for each structure clearly drawn and correctly labelled.
light and dark bands;
Z line;
(thin) actin filaments shown with no gap between these and Z line;
(thick) myosin filaments shown with heads;	3 max
 
(b)	binds oxygen when level is high;
releases oxygen when level is low;
acts as an oxygen store;
allows muscles to continue with aerobic respiration for longer;	2 max
[5]

197.	(a)	(with exercise) switch to anaerobic respiration from aerobic respiration;
switch from fat to carbohydrate;
eventually no fat respired / 100% of respiration of carbohydrate;	2 max
 
(b)	blood flow to brain unchanged with exercise;
blood flow to heart wall/skeletal muscles/skin increased with exercise;
blood flow to kidneys/stomach/intestines/other abdominal organs reduces
with exercise;	2 max
 
(c)	speed is how quickly the body/body parts move a given distance
per unit time;
stamina is the capacity of sustaining effort/exercise level;
if exercise not sufficiently challenging, then stamina appears higher
than expected;
the appropriate fitness measure depends on a particular activity;
stamina is important for endurance sports e.g. marathon running;	3 max
[7]

198.	B
[1]

199.	B
[1]

200.	C
[1]

201.	C
[1]

202.	A
[1]

203.	D

204.	(a)	200%	1
 
(b)	IDE – / – mice do not have the enzyme to break down insulin; (accept converse)
therefore insulin levels higher in IDE – / – mice / lower in IDE + / + mice;	2
 
(c)	in IDE + / + mice, glucose (levels in the blood) peaks / starts to reduce
after 30 minutes / in IDE – / – mice, glucose levels remain high for
longer / continues to rise for 60 minutes;
blood glucose level is always higher in IDE – / – mice than in IDE + / +
mice / blood glucose level in IDE + /+ mice decreases rapidly to
original level but remains high in IDE – / – mice;	2

(d)	both blood glucose and insulin levels are higher in IDE – / – mice /
high blood glucose levels and insulin levels are seen in type II diabetes;
due to this, IDE – / – mice are a good model for type II diabetes; (to award
this mark answer needs justification)	2

(e)	(in both cases) when insulin is present control mice are better at taking up
glucose than MIRKO mice;
no insulin receptors in skeletal muscle of MIRKO mice; (accept converse)	2
 
(f)	exercise increases glucose uptake more than insulin
Award [0] for simply just restating figures.	1
 
(g)	exercise stimulates glucose uptake into muscle / exercise lowers blood glucose;
exercise is more effective in reducing blood glucose in MIRKO
mice (than in control mice);
exercise and insulin combined are more effective in both (MIRKO
and control) mice;
exercise combined with insulin would be an appropriate therapy;	3 max
 
(h)	cells: β cells (in islets of Langerhans);
organ: pancreas;	2
 
(i)	glucagon / adrenaline / cortisol	1
[17]

205.	(a)	active immunity is by the production of antibodies by the body and
passive immunity is when antibodies are obtained from an external source;
in active immunity the individual is exposed to the antigen/pathogen/
has the disease and in passive immunity the individual is not exposed;
active immunity gives rise to memory cells and passive immunity does not;	2 max
 
(b)	B lymphocytes are produced in laboratory animal after injection with an
antigen;
animal cells/these cells are fused with tumour cells (to form hybridomas
which) produce antibodies;	2
 
(c)	HIV virus transmitted by body secretions/semen/blood/across placenta;
transmitted by infected blood transfusions/intravenous drug users;
mainly by sexual activity/promiscuity;	2 max

(d)	antibiotics block metabolic pathways / work only on bacteria;
viruses reproduce using their hosts’ metabolic pathways / do not
have their own metabolic pathways;	2
[8]

206.	(a)	Award [1] for each structure clearly drawn and correctly labelled.
Sarcomere — clearly indicated between Z lines;
Z lines;
actin filaments attached to Z line;
myosin filaments with heads;
(two) light bands;
dark band;	4 max
 
(b)	calcium ions are released from the sarcoplasmic reticulum;
they expose the myosin binding sites (on actin) / cause movement of
blocking molecules/troponin;
cross-bridges form between actin and myosin molecules;
ATP provides energy;
for actin filaments to slide over the myosin filaments / for myosin to
push actin;
ATP provides energy to release myosin from binding site;
action can be repeated further along the molecule;	5 max
 
(c)	the resting potential of cell is negative inside compared with outside;
stimulation causes depolarization/reversal of charge on each side;
due to Na+ channels opening / Na+ flowing into the cell;
which causes an action potential;
K+ channels open / K+ flows out of the cell;
sodium potassium pump restores resting potential;
transmitted between neurons across a synapse;
neurotransmitter released into synaptic cleft;
diffuse across cleft to postsynaptic membrane;
where they bind to receptors;
influx of Na+ into cell;
which may initiate action potential;	9 max
	(Plus up to [2] for quality)
[20]

207.	(a)	
S curve correctly drawn;
lag phase;
exponential/log phase;
population growth slowing down / transitional phase / environmental resistance;
plateau phase;
To award marks phases must be labelled not just drawn.
Award [3 max] if no axes shown.	4 max
 
(b)	production of sperm/spermatozoa in the testes/seminiferous tubules;
first stage of sperm production requires divisions by mitosis;
cells then undergo a period of growth;
future sperm cells then undergo two meiotic divisions;
cells then differentiate to form sperm cells;
nourished by Sertoli cells
number becomes haploid / chromosome number halved / 46 to
23 chromosomes;	5 max
 
(c)	embryonic/disc shaped structure that nourishes the developing embryo;
starts forming at implantation of the blastocyst/embryo;
embryonic tissue invades/grows into the uterine wall;
fetal capillaries exchange material with maternal blood/lacunae;
allows exchange of food/oxygen/antibodies from mother’s blood to fetus;
allows exchange of carbon dioxide/waste products from fetal blood to mother;
connected to the embryo/fetus by an umbilical cord;
placenta takes over hormonal role of ovary;
indication of time this happens / at approximately 12 weeks;
secretes estrogen/progesterone;
hormone secretion maintains pregnancy;
expelled from uterus after childbirth;	9 max
	(Plus up to [2] for quality)
[20]

208.	(a)	water has a high specific heat capacity;
a large amount of heat causes a small increase in temperature;
water has a high latent heat of vaporization;
a large amount of heat energy is needed to vaporize/evaporate water;
hydrogen bonds between water molecules make them
cohesive/stick together;
this gives water a high surface tension / explains how water rises
up xylem;
water molecules are polar;
this makes water a good solvent;
Award [4 max] if thermal, cohesive and solvent properties are not
all mentioned.	5 max

(b)	xerophytes are plants that live in dry conditions;
reduced leaves/spines to prevent water loss (by transpiration);
rolled leaves to prevent water loss / stomata on the inside / sunken stomata;
thick waxy cuticle/hairs on leaves to prevent water loss (by transpiration);
reduced stomata to prevent water loss (by transpiration) / stomata on
one side of leaf;
deep/widespread roots to obtain more water;
special tissue for storing water;
take in carbon dioxide at night / CAM plant to prevent water loss;	4 max
 
(c)	process of water balance is called osmoregulation;
water passes into the kidney tubules by ultrafiltration;
water is reabsorbed in the proximal convoluted tubule;
water reabsorbed into blood from the (descending limb) of the
loop of Henle;
process by osmosis;
transport of salts into the medulla of kidney;
changes salt concentration so water is reabsorbed;
ADH released into blood when water is required;
ADH causes concentrated urine / no/low ADH causes dilute urine;
this causes more reabsorption of water from the collecting duct;
excess water is released as urine;
urine concentration depends on the body’s need for water;
drinking a lot gives dilute urine;	9 max
	(Plus up to [2] for quality)
[20]

209.	(a)	 × 100;
= 69%; (accept correct answer that is not rounded up to 69%)	2
 
(b)	higher percentage of those with stomach cancer have H. pylori infection;
higher median of those with stomach cancer have H. pylori infection;
infection/high level antibodies does not mean that gastric cancer will
always result / many infected did not develop gastric cancer;
not all of those with stomach cancer had H. pylori infection;	3 max
 
(c)	pepsinogen would not be broken down to pepsin;
pepsin would not work as well due to incorrect pH;
it is not known if humans would respond in the same way as gerbils;	2 max
[7]

210.	(a)	(i)	microvilli/microvillus	1

(ii)	epithelial cell/enterocyte	1
 
(b)	chemical (messengers) secreted by (endocrine) glands;
into the blood / transported by the blood;
act on target organs/cells;	2 max
 
(c)	hepatic artery carries oxygenated blood;
hepatic portal vein carries blood from gut/deoxygenated blood;
blood from hepatic portal vein and hepatic artery mix;
flows through sinusoids;
hepatic vein carries blood away from liver;	3 max
[7]

211.	during exercise the rate of tissue respiration increases/more carbon dioxide produced;
carbon dioxide production in the tissues exceeds the rate of breathing it out;
increase in carbonic acid / increase in H+ ions / pH drops in the blood plasma;
lactic acid (in strenuous exercise) reduces pH;
chemoreceptors/chemosensors detect change in pH/increase in carbon dioxide/
decrease in oxygen;
receptors in the carotid/aortic bodies;
nerve impulses sent to the breathing centres of the brain;
nerve impulses then sent to diaphragm/intercostal muscles;
negative feedback control;	6 max
[6]

212.	D
[1]

213.	B
[1]

214.	B
[1]

215.	C
[1]

216.	D
[1]

217.	B
[1]

218.	A
[1]

219.	(a)	Award [1] for two of the following
pre-natal development of male genitalia;
development of male secondary sexual characteristics / name of
specific characteristic;
maintenance of sex drive;	1 max
 
(b)	red-green colour-blindness is a sex-linked character / gene located on
X-chromosome;
boy inherits X chromosome from mother, only inherits Y chromosome
from father;
boy’s mother must have been carrying the gene;
he inherited it from mother’s father / maternal grandfather;	3 max
[4]

220.	(a)	Award [1] for each structure correctly drawn and labelled.
esophagus — attached to both mouth and stomach;
stomach — j-shaped sac attached to esophagus and u-shaped portion of
small intestine;
large intestine — wider diameter than small intestine, attached to small intestine;
pancreas — leaf-shaped, in u-shaped region of small intestine with small duct
connected to small intestine;
liver — large, triangular, to left of stomach;
gall bladder — small sac drawn on top of liver with tube connected to small
intestine at same region as duct from pancreas;
anus —at end of large intestine but narrower in diameter;	4 max

(b)	at low temperatures, rate of reaction increases as temperature increases
(or vice versa);
	more kinetic energy / faster movement of molecules means more collisions
between enzyme / active site and substrate;
	optimum temperature is temperature at which rate of enzyme-catalyzed
reaction is fastest;
at high temperatures enzymes are denatured and stop working;
denatured means change of structure in enzyme / protein resulting in loss of its
biological properties / no longer can carry out its function;
	too much kinetic energy / vibrations breaks bonds that give enzyme specific
shape;
optimum pH is one at which rate of enzyme-catalyzed reaction is fastest;
rate of reaction reduced as increase or decrease pH (from optimum);
strong acids and alkalis can denature enzymes;
affect (weak, ionic, hydrogen) bonds that hold enzyme in specific shape;
at low substrate concentrations, as increase concentration get increase in rate
of reaction;
more chance of collision between substrate and enzyme / active site;
	at high substrate concentration, have no change in rate as increase
concentration;
all active sites occupied;	9 max
 
(c)	lactose intolerance high in some human populations / Asian / African / native
American and Australian aboriginal populations;
lactase used to produce lactose-free / low-lactose milk;
lactase breaks down lactose to glucose and galactose;
source of lactase is usually yeast / many sources such as bacteria, moulds;
milk passed over immobilized lactase / lactase bound to inert substance;
increase sweetness of milk;
no need to add extra sugar in manufacture of flavoured milk drinks / 
frozen desserts;
can add (harmless) bacterium such as L.acidophilus which has same effect on
lactose as in yoghurt;	5 max
(Plus up to [2] for quality)
[20]

221.	(a)	Portugal	1
 
(b)	Iceland	1
 
(c)	both showed an increase in energy consumption;
USA showed a greater relative increase in the proportion of dietary energy from
plant origin;
USA overtook the 15 European nations group in daily dietary
energy consumption;	2 max

(d)	increase in dietary energy intake / energy intake in all countries exceeds
recommended daily intake;
likely consequence is obesity;
animal source of energy linked to intake of saturated fat;
some countries have shown an increased consumption of animal source energy;
	pattern for increase in animal source energy is less uniform coupled with
decrease in exercise / manual labour;	3 max
[7]

222.	(a)	minerals are usually elements whereas vitamins are compounds;
minerals are inorganic while vitamins are organic;	2
 
(b)	iodine deficiency can lead to goitre / mental retardation;
iodine is necessary for thryoxine production;
dietary supplementation usually through iodized salt;
cost to supplement is minimal but cost of deficiency is high;
few foods rich in iodine / lack of marine food in diet can lead to deficiency;	3 max
[5]

223.	(a)	protein and carbohydrate have similar energy content per gram / both have
approximately 1700 kJ per 100g;
	100 g of fat has more than twice the energy content of 100 g of carbohydrate
or 100 g of protein;	2
 
(b)	causes [2 max]:
	genetic component / high-risk ethnic group (Aboriginal, Asian, Pacific
Islander, Hispanic, Pima);
obesity (BMI > 27 kg / m2) / diets high in fat / sugar;
symptoms [2 max]:
poor ability to clear glucose from the blood is used to diagnose / high
blood glucose;
frequent urination / thirst / tiredness;
glucose detected in urine;	4 max
[6]

224.	(a)	(i)	as treadmill speed increases, tidal volume increases	1
(ii)	at high treadmill speeds, tidal volume begins to level off / rate of
increase slows	1
 
(b)	ventilation rate continues to increase while tidal volume decreases / levels off	1

(c)	ventilation rate × tidal volume;
116 L ± 4 L;	2
 
(d)	ventilation rate would increase (until a physical limit was reached);
tidal volume would level off / decrease / physical limit would be reached;	2
[7]

225.	(a)	synovial fluid: lubricates joints (to reduce friction);
joint capsule: seals the joint / encloses the synovial fluid;	2
 
(b)	tendon	1
 
(c)	a sudden violent movement of joint / extension of joint beyond normal range;
leads to soft tissue damage;
torn or stretched ligament;	2 max
[5]

226.	(a)	ATP provides energy for muscle contraction;
(binding of) ATP causes myosin heads to detach / breaks cross-bridges (from
their actin binding sites);
(hydrolysis of) ATP causes cocking of myosin heads / change in their angle;	2 max
 
(b)	taken by body builders as it is reputed to increase muscle mass;
some suggest that mass gains are due to increased water retention;
high intensity anaerobic sports report performance enhancement;
less certain results for swimming and running;
upper limit to amount body can store;
supplementation not recommended for adolescents / people with
kidney dysfunction;
supplementation may suppress the body’s natural synthesis;	4 max
[6]

227.	(a)	Award [1] for any two of the following:
chemoreceptors / baroreceptors / thermoreceptors / photoreceptors / 
propioreceptors	1
 
(b)	processing of stimuli which takes place on the opposite side of where the
stimuli was detected / where the right brain processes information from
the left visual field	1

(c)	cilia on hair cells vary in length;
each resonates to a different frequency of sound;
complex sounds are resolved into their components;
	inner hair cells send message to the brain / outer hair cells receive signals
from the brain;	3 max
[5]

228.	(a)	(i)	Award [1] for any two of the following:
nicotine / cocaine / amphetamines	1
(ii)	increase sense of intensity of perceived sensory data / sense of emotional
	well-being / concentration reduced / impaired judgment of time and
space	1
 
(b)	addiction is dependence on a substance (such as alcohol or other drugs) or
an activity;
	stopping is very difficult and causes severe physical / mental reactions / 
complex behaviour;
predisposition may be determined by polygenic inheritance;
significant role of environmental factors;
dopamine released in response to reward / eg food;
some drugs / heroin / cocaine enhance dopamine activity;
abuse drugs hypothesized to lead to down-regulation of dopamine receptors;
requires increasing amounts to achieve same effect;	4 max
[6]

229.	(a)	(i)	1967	1
(ii)	(death rate = 5 per 100,000 / yr, total number of deaths would be 5
times 198 =) 990 deaths	1
 
(b)	death rate in Canada is always lower than United Kingdom;
	highest death rate in United Kingdom approx 40 per 100,000 whereas in
Canada never above 15;
no death from influenza recorded in Canada in 1957 but some in the
United Kingdom;
	highest death rate for United Kingdom recorded in 1953 but in Canada
in 1958;
both countries have very low / zero death in 1954 and 1957;
between 1953 and 1963 patterns are very similar;	3 max

(c)	viruses consist of nucleic acid and a protein coat;
DNA double stranded or single stranded;
RNA double stranded or single stranded;
protein coat contains receptors specific for target organism;	2 max
[7]

230.	B
[1]

231.	B
[1]

232.	D
[1]

233.	C
[1]

234.	(a)	at lower concentration inhibition is low;
	as concentration rises from 5-20 mmol dm –3 there is very little
increase in inhibition;
from 20 mmol dm–3 inhibition increases in a linear manner;
a valid comparison with another of the peptides;	2 max
 
(b)	no effect on S. aureus, inhibits growth of C. albicans;
	no change on S. aureus as concentration increases, inhibition of C.
albicans increases with concentration;	2
 
(c)	at lowest (experimental) concentration (LL-37) does not have effect on
either;
as concentration increases so does inhibition;
greater inhibition of C. albicans;
effective against C. albicans but not / less effective on S aureus;	3 max
 
(d)	LLG	1

(e)	18 - 2 = 16 /  ´ 100% / 8 ´ 100%;
800%;	2
 
(f)	LLG / naturally occurring peptide less effective;
LL-37 less effective than GKE / FKR;
LL-37 damages DNA (significantly) at more than 6 μmol dm–3;
LL-37 may kill cells at higher concentrations;
GKE / FKR could be used at lower concentrations;
GKE / FKR cause slight DNA damage at lower concentrations;
GKE is (slightly) more effective;
GKE causes increased DNA fragmentation at higher concentrations;	4 max
 
(g)	b-sheet / b-pleat	1
 
(h)	sharp peak, strong chance around 20–25;
smaller peak, strong chance at around 4–6;
no likelihood above 32 / 33 / at end of molecule;
appropriate description eg chance increases from 13 / 14 to 20 / 25;	2 max
 
(i)	dipeptide showing N terminal and C terminal ends;
a hydrogen and an R group attached to each α carbon;
	a link between the carbon of the C=O group of one amino acid and the
nitrogen of the N-H of the other correctly labelled;	2 max
	eg

[19]

235.	(a)	Award [1] for each of the following clearly drawn and correctly labelled.
cell body — complete with nucleus and dendrites;
axon—shown longer than the longest dendrite, with the membrane drawn as a
continuous line;
myelin sheath — surrounding the axon, showing nodes of Ranvier;
motor end plates — not covered by myelin sheath and ending in a button / dot;	4

(b)	heart muscle is myogenic / pacemaker;
rise in CO2 detected in medulla of brain;
nerve impulse sent to pacemaker;
sympathetic / parasympathetic control;
modifies heart beat;
SA node initiates contraction of atria;
impulses (from SA) cause AV node to contract ventricles;
transmitted through Purkinje fibres;
output rises;
CO2 level falls;	6 max
Allow converse of above
 
(c)	(skeletal) muscle is composed of myofibrils;
operational unit is a sarcomere;
viewed as a series of light and dark bands;
thin actin fibres;
thick myosin fibres;
arrival of action potential;
release of Ca2+;
from sarcoplasmic reticulum;
exposes binding sites of myosin fibres;
ATP used to break cross bridges between myosin and actin fibres;
hydrolysis of ATP resets myosin head;
causing sliding of actin and myosin;	8 max
(Plus up to [2] for quality)
[20]

236.	(a)	Award [1] for each structure correctly drawn and labelled.
esophagus — attached to both mouth and stomach;
stomach — j-shaped sac attached to esophagus and u-shaped portion of
small intestine;
large intestine — wider diameter than small intestine, attached to small intestine;
pancreas —eaf-shaped, in u-shaped region of small intestine with small duct
connected to small intestine;
liver — large, triangular, to left of stomach;
gall bladder — small sac drawn on top of liver with tube connected to small
intestine at same region as duct from pancreas;
anus —at end of large intestine but narrower in diameter;	4 max
 
(b)	large molecules cannot be absorbed;
mechanical digestion only to break down food physically;
enzymes breakdown large molecules into smaller ones (that can be absorbed);
need several enzymes as they are substrate specific;
enzymes speed up the rate of digestion considerably;
higher speeds at low / normal body temperature;
named example of enzyme;
example of named enzyme’s action;	6 max
 
(c)	important that some products of digestion not lost;
products in the blood stream;
ultrafiltration in the glomerulus;
fenestrated capillaries / podocytes;
basement membrane acts as the filter;
proteins too large to pass through;
importance of proximal convoluted tubule;
reabsorption of salts / glucose / ions / other named substance;
microvilli;
details of active transport;
osmosis is the reabsorption of water;
detail of osmoregulation;	8 max
(Plus up to [2] for quality)
[20]

237.	(a)	A: pinna;
B: eardrum;
C: stapes / bones of the middle ear;
D: semicircular canals;	2 max
Award [2] for 4 correct answers, [1] for three correct answers, [0] for two or one correct answer(s)
 
(b)	(a stimulus is) a change in the environment (internal or external) that
is detected by a receptor and elicits a response	1
 
(c)	the sympathetic and parasympathetic systems are part of the ANS;
the sympathetic and parasympathetic systems are antagonistic;
	the sympathetic system accelerates the heart rate and stimulates glucose
release (from the liver);
more blood is pumped to the muscles and the intestines;
the sympathetic system (mostly) uses norepinephrine (noradrenaline);
	the parasympathetic system slows down heart rate and stimulates the
stomach and the intestines;
body relaxes and blood flow slows down;
the parasympathetic system (mostly) uses acetylcholine;	4 max
[7]

238.	(a)	(i)	1967	1
(ii)	(death rate = 5 per 100,000 / yr, total number of deaths would be 5
times 198) = 990 deaths	1

(b)	death rate in Canada is always lower than United Kingdom;
	highest death rate in United Kingdom approx 40 per 100,000 whereas
in Canada never above 15;
no death from influenza recorded in Canada in 1957 but some in the
United Kingdom;
	highest death rate for United Kingdom recorded in 1953 but in Canada
in 1958;
both countries have very low / zero death rate in 1954 and 1957;
between 1953 and 1963 patterns are very similar;	3 max
 
(c)	higher population density in United Kingdom facilitated spread;
	may not have been the same viral strain that caused the epidemic / 
viral strain may have mutated;
UK population had more elderly people than Canadian population;
	winters more severe in Canada so people are inside more and thus
less contact;
winter clothes prevent spread of virus;
winter in the UK may have been particularly harsh;
differences in the (genetically) susceptibility;	2 max
[7]

239.	(a)	protozoan parasite, Plasmodium falciparum, has insect host Anopheles mosquito;
a mosquito bites infected human / human suffering from malaria and ingests
(gametocytes) parasite;
parasite has a (sexual) life cycle in mosquito / produces sporocytes;
when mosquito bites another human it injects parasite into bloodstream;
human falls ill with malaria and produces parasites in bloodstream;	2 max
 
(b)	prions are infectious proteins / proteinaceous particles;
transmission can be by eating contaminated food;
prions cause a number of degenerative brain diseases;
	Creutzfeld - Jakob disease in humans / scrapie in sheep / mad cow disease
(BSE, bovine spongiform encephalopathy) in cattle;
prions are formed from naturally occurring proteins found in brain cells;
can occur in two forms / PrPsc and PrPc;
	PrPsc is the misfolded form / different conformation, and PrPc is the
normal form / wild type;
PrPsc can act as a mould and cause PrPc to misfold;
PrPsc is the cause of the degenerative brain diseases;
PrPc is a protein occurring naturally in brain cell membranes;
function of PrPc is unknown;
PrPsc is resistant to proteases / high temperatures;	5 max
[7]

240.	(a)	(i)	patients were fed / plasma glucose / blood insulin levels start to rise after
intake of food	1 max
(ii)	147 (±1) mg 100ml–1 (units required)	1
 
(b)	both glucose and insulin rise after a meal / at specific times during the day;
both have a trough at 11:00 and 17:00 and end concentrations almost the same;	2
 
(c)	blood insulin and glucose seem to have been lowered by the high fibre diet;
more pronounced decrease of concentration after morning meal / 8 am than after
dinner / 5 pm;
less fluctuation in insulin and glucose levels in the high fibre diet;
effect of high fibre seems to persist even when no food is consumed / after 1 am;
	standard error for most data points is such that no valid conclusion can be
drawn;	3 max
[7]

241.	(a)	Award [1] for three of the following
cellulose / lignin / bile pigments / bacteria / intestinal cells	1
 
(b)	erythrocytes rupture when they reach the end of their life span / after 120 days;
absorbed by phagocytosis / Kupffer cells in liver from blood;
hemoglobin split into globin and heme groups;
iron removed from heme leaving bile pigment / bilirubin;
bilirubin released into alimentary canal;
digestion of globin to produce amino acids;	4 max
[5]

242.	(a)		2 max
protein hormones	steroid hormones	
do not enter cells / do not pass through plasma
membrane	pass through plasma membrane;	
bind to receptors on the outside of the cell	form complex with cytoplasmic receptors;	
causes release of a secondary messenger
inside the cell	can act as transcriptional regulators;	

(b)	SA (sino atrial) node / pacemaker receives signal to fire;
when ventricle 70% / almost full;
AV (atrio ventricular) valve opens and blood fills ventricle (to maximum) / 
atrial systole;
pressure increase in ventricle closes AV valve / ventricular systole;
AV node fires;
Purkinje fibres carry impulses to all areas of ventricles for simultaneous firing;
pressure increase causes semilunar valve to open;
blood pumped from ventricle to aorta / systole sound / ventricular diastole;
pressure lowers in ventricle closing semilunar valve / diastole sound;
pressure in ventricle lower than atria so AV valve opens;
increases blood ventricular volume;
both atria and ventricles are relaxed / diastole;
atria receive blood from veins;
cycle repeats;	6 max
[8]