1.	Which of the following will contribute to the cell theory?
I.	Living organisms are composed of cells.
II.	All cells come from pre-existing cells by mitosis.
III.	Cells are the smallest units of life.
A.	I only
B.	II only
C.	I and III only
D.	I, II and III
(Total 1 mark)

2.	A red blood cell is 8 μm in diameter. If drawn 100 times larger than its actual size, what diameter will the drawing be in mm?
A.	0.08 mm
B.	0.8 mm
C.	8 mm
D.	80 mm
(Total 1 mark)

3.	A cell has cytoplasm, a cell wall, naked DNA and ribosomes. Based on this information, what type of cell could this be?
A.	A cell from a pine tree
B.	A grasshopper cell
C.	A human red blood cell
D.	A bacterium
(Total 1 mark)

4.	What do diffusion and osmosis have in common?
A.	They only happen in living cells.
B.	They require transport proteins in the membrane.
C.	They are passive transport mechanisms.
D.	Net movement of substances is against the concentration gradient.
(Total 1 mark)

5.	The diagram below shows a cell during mitosis.
		
	What are the structures and stage of mitosis?

	Stage of mitosis	Structure I	Structure II	
A.	metaphase	chromatid	nuclear membrane	
B.	anaphase	centromere	plasma membrane	
C.	anaphase	chromatid	nuclear membrane	
D.	metaphase	centromere	plasma membrane	
(Total 1 mark)

6.	Which of the following characteristics found in a structure necessarily indicates that it is alive?
A.	The presence of genetic material
B.	The presence of a lipid bilayer
C.	Metabolism
D.	Movement
(Total 1 mark)

7.	Which of the following does not occur during interphase?
A.	Replication
B.	Translation
C.	Cytokinesis
D.	An increase in the number of mitochondria
(Total 1 mark)

8.	Which pair of features is correct for both a human liver cell and an Escherichia coli cell?

	Human liver cell	Escherichia coli cell	
A.	contains DNA associated with protein	contains naked DNA	
B.	has 70S ribosomes	has 80S ribosomes	
C.	contains mitochondria	contains mitochondria	
D.	contains DNA enclosed by a membrane	contains DNA associated with protein	
(Total 1 mark)

9.	If a mitochondrion has a length of 5 µm and a student’s drawing of the mitochondrion is 10 mm, what is the magnification of the drawing?
A.	×0.0005
B.	×0.5
C.	×200
D.	×2000
(Total 1 mark)

10.	PanI is a gene in cod fish that codes for an integral membrane protein called pantophysin.
Two alleles of the gene, PanIA and PanIB, code for versions of pantophysin, that differ by four amino acids in one region of the protein. Samples of cod fish were collected from 23 locations in the north Atlantic and were tested to find the proportions of PanIA and PanIB alleles in each population. The results are shown in pie charts, numbered 1–23, on the map below. The proportions of alleles in a population are called the allele frequencies. The frequency of an allele can vary from 0.0 to 1.0. The light grey sectors of the pie charts show the allele frequency of PanIA and the black sectors show the allele frequency of PanIB.
		
	[RAJ Case et al. 2005.  “Macro- and micro-geographic variation in pantophysin (PanI) allele frequencies in NE Atlantic cod Gadus morhua.” MEPS. Vol 301. Pp 267–278. Figs 1 and 3.]
 
(a)	(i)	State the two populations with the highest PanIB allele frequencies.
...........................................................................................................................
(1)
 
(ii)	State the population in which the allele frequencies were closest to 0.5.
...........................................................................................................................
(1)
 
(b)	Deduce the allele frequencies of a population in which half of the cod fish had the genotype PanIA PanIA, and half had the genotype PanIA PanIB.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(1)
 
	The graphs below show the latitude and the mean surface sea temperature in June of the sampling locations and the frequency of the PanIA allele.

	[RAJ Case et al. 2005.  “Macro- and micro-geographic variation in pantophysin (PanI) allele frequencies in NE Atlantic cod Gadus morhua.” MEPS. Vol 301. Pp 267–278. Figs 1 and 3.]
 
(c)	State the relationship between
(i)	latitude and the frequency of the PanIA allele.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)	mean surface sea temperature in June and the frequency of the PanIA allele.
...........................................................................................................................
...........................................................................................................................
(1)
 
(d)	Suggest how natural selection could have caused the relationships shown in the graphs.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)

(e)	The sites close to Iceland, at a latitude of 60–65°, had very varied allele frequencies, with both PanIA and PanIB occurring. The water at these sample sites was highly stratified, with much warmer water at the surface and much colder water below. Suggest reasons for both PanIA and PanIB alleles occurring at these sites.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(f)	Using the data in this question, predict the effects of global warming on cod fish populations.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 11 marks)

11.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Escherichia coli is a unicellular organism, so each cell must carry out all of the processes required for life. Outline the functions of each of the structures in the cells of Escherichia coli.
(9)
 
(b)	Compare the use of carbohydrates and lipids in energy storage.
(4)
 
(c)	Compare how pyruvate is used in human cells when oxygen is available and when oxygen is not available.
(5)
(Total 20 marks)

12.	The electron micrograph below shows the ultrastructure of part of an animal cell.
		
	[Source: Reproduced with the kind permission of the Electron Microscopy Facility, Trinity College, Hartford, Connecticut, USA, and Professor Daniel G. Blackburn.]

(a)	Identify the structure labelled I.
......................................................................................................................................
(1)
 
(b)	Explain briefly how materials produced in the structure labelled I are transported to the plasma membrane.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(c)	Outline the function of the mitochondria in the cell.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(d)	Suggest why the two labelled mitochondria are different shapes in the micrograph.
......................................................................................................................................
(1)
(Total 6 marks)

13.	The electron micrograph below shows an organelle in a eukaryotic cell. What is the area labelled X and what is the type of reaction occurring there?
		
[Source: http://scienceblogs.com/clock/2006/11/cell_structure.php]

	X	Reaction	
A.	matrix	photolysis	
B.	stroma	Krebs cycle	
C.	stroma	photolysis	
D.	matrix	Krebs cycle	
(Total 1 mark)

14.	In which of the following cells can more than one nucleus be found?
A.	An unfertilized egg
B.	Neuron
C.	Sertoli cell
D.	Muscle fibre
(Total 1 mark)

15.	Which of the following does not occur during interphase?
A.	Replication
B.	Translation
C.	Cytokinesis
D.	An increase in the number of mitochondria
(Total 1 mark)

16.	This question refers to the following micrograph of a liver cell.
		
	In which organelle does the production of ATP, due to chemiosmosis, occur?
A.	A
B.	B
C.	C
D.	D
(Total 1 mark)

17.	This question refers to the following micrograph of a liver cell.
		
	Structure X is the Golgi apparatus. What process occurs in this organelle?
A.	Post-transcriptional modification of mRNA
B.	Translation
C.	mRNA production
D.	Vesicle formation
(Total 1 mark)

18.	The micrograph below shows an adult human stem cell.
		
[© Science Photo Library. Used with permission.]
 
(a)	The cell cycle can be divided into two parts: interphase and mitosis.
(i)	Identify, with a reason, whether the stem cell in the micrograph is in interphase or mitosis.
...........................................................................................................................
...........................................................................................................................
(1)
 
(ii)	Deduce two processes that occur in human cells during this part of the cell cycle, but not during the other part.
1. .......................................................................................................................
2. .......................................................................................................................
(2)

(b)	State two characteristics of stem cells that can be used to distinguish them from other body cells.
1. ..................................................................................................................................
2. ..................................................................................................................................
(2)
 
(c)	Outline one therapeutic use of stem cells.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
(Total 8 marks)

19.	Which functions of life are found in all unicellular organisms?
A.	growth, response and nutrition
B.	differentiation, response and nutrition
C.	metabolism, meiosis and homeostasis
D.	growth, metabolism and differentiation
(Total 1 mark)

20.	Which statement is part of the cell theory?
A.	Cells are composed of organic molecules.
B.	Cells have DNA as their genetic material.
C.	Cells have cytoplasm surrounded by a membrane.
D.	Cells come from pre-existing cells.
(Total 1 mark)

21.	Which of the following are features of prokaryotes and eukaryotes?

	70S ribosomes	80S ribosomes	Naked DNA	DNA associated with proteins	
A.	prokaryote	eukaryote	prokaryote	eukaryote	
B.	eukaryote	prokaryote	eukaryote	prokaryote	
C.	eukaryote	prokaryote	prokaryote	eukaryote	
D.	prokaryote	eukaryote	eukaryote	prokaryote	
(Total 1 mark)

22.	What route is used to export proteins from the cell?
A.	Golgi apparatus → rough endoplasmic reticulum → plasma membrane
B.	Rough endoplasmic reticulum → Golgi apparatus → plasma membrane
C.	Golgi apparatus → lysosome → rough endoplasmic reticulum
D.	Rough endoplasmic reticulum → lysosome → Golgi apparatus
(Total 1 mark)

23.	Which events occur during the G1 phase and S phase of the cell cycle?

	G1 phase	S phase	
A.	DNA replicates	cell grows	
B.	mitosis begins	cell divides	
C.	cell divides	mitosis begins	
D.	cell grows	DNA replicates	
(Total 1 mark)

24.	In a cell, what is the effect of a large surface area to volume ratio?
A.	Slower rate of exchange of waste materials
B.	Faster heat loss
C.	Faster rate of mitosis
D.	Slower intake of food
(Total 1 mark)

25.	How can cells in a multicellular organism differentiate?
A.	They express some of their genes but not others.
B.	They all have a different genetic composition.
C.	Different cells contain a different set of chromosomes.
D.	Different cells do not have some of the genes.
(Total 1 mark)

26.	The diagram below shows a bacterium.
		
	What structure does the part labelled X identify?
A.	Nucleus
B.	Nucleoid
C.	Nucleolus
D.	Nuclear membrane
(Total 1 mark)

27.	What do prokaryotic cells have that eukaryotic cells do not?
A.	Mitochondria
B.	70S ribosomes
C.	Histones
D.	Internal membranes
(Total 1 mark)

28.	What happens during the G2 stage of interphase?
A.	Homologous chromosomes pair
B.	Synthesis of proteins
C.	Homologous chromosomes separate
D.	Replication of DNA
(Total 1 mark)

29.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Explain why DNA must be replicated before mitosis and the role of helicase in DNA replication.
(4)
(b)	Explain how the base sequence of DNA is conserved during replication.
(5)
(c)	Describe the events that occur during mitosis.
(9)
(Total 20 marks)

30.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Plants are a diverse group of eukaryotic organisms. Describe the different characteristics of the bryophyta, filicinophyta, coniferophyta and angiospermophyta.
(9)
(b)	Plants store carbohydrate in the form of starch. Explain the reasons for starch being digested by the human digestive system.
(4)
(c)	Compare the structure of prokaryotic and eukaryotic cells.
(5)
(Total 20 marks)

31.	(a)	Outline the bonding between DNA nucleotides.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(b)	Explain how chemical bonding between water molecules makes water a valuable coolant in living organisms.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
 
(c)	Describe the movement of water across membranes.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)

(d)	State the role of water in photosynthesis.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 8 marks)

32.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Compare simple diffusion with facilitated diffusion as mechanisms to transport solutes across membranes.
(5)
(b)	Describe the process of endocytosis.
(5)
(c)	Explain how an impulse passes along the membrane of a neuron.
(8)
(Total 20 marks)

33.	Which of the following take(s) place during either interphase or mitosis in animal cells?
I.	Re-formation of nuclear membranes
II.	Pairing of homologous chromosomes
III.	DNA replication
A.	I only
B.	I and II only
C.	II and III only
D.	I and III only
(Total 1 mark)

34.	What is the function of the cytoplasmic (plasma) membrane of this bacterium?
		
A.	To produce ADP
B.	To form the only protective layer preventing damage from outside
C.	To control entry and exit of substances
D.	To synthesize proteins
(Total 1 mark)

35.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Eukaryotic cells have intracellular and extracellular components. State the functions of one named extracellular component.
(4)
 
(b)	Outline, with an example, the process of exocytosis.
(5)
 
(c)	Translation occurs in living cells. Explain how translation is carried out, from the initiation stage onwards.
(9)
(Total 20 marks)

36.	(a)	The scanning electron micrograph below shows the surface of the nuclear envelope with numerous nuclear pores.
		
[Source: adapted from D Nelson and M Cox, (2000), Lehninger Principles of Biochemistry, third edition, page 35]

(i)	Calculate the power of magnification of the image.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
 
(ii)	State the diameter of the pore labelled X.
...........................................................................................................................
(1)
 
(b)	List two examples of how human life depends on mitosis.
......................................................................................................................................
......................................................................................................................................
(1)
 
(c)	Describe the importance of stem cells in differentiation.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
 
(d)	The graphs below show the normal menstrual cycle.

[Source: adapted from www.mivf.com.au/ivf/infertility/images/cyclediagram.GIF]
 
(i)	Predict, with a reason, how the graphs will change if the woman becomes pregnant.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(ii)	List two roles of testosterone in males.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
(Total 9 marks)

37.	What is the sequence of stages during the cell cycle?
A.	    G1     →    S    →     G2    →    mitosis     → cytokinesis
B.	mitosis →    G1   →     G2    → cytokinesis →         S
C.	    G1    →    G2   →      S     →    mitosis     → cytokinesis
D.	     G1   →    G2   → mitosis → cytokinesis →         S
(Total 1 mark)

38.	What is the difference between the structure of all prokaryotes and all eukaryotes?

	Prokaryotes	Eukaryotes	
A.	cell wall	no cell wall	
B.	chloroplasts	no chloroplasts	
C.	flagellum	no flagellum	
D.	nucleoid	nuclear envelope	
(Total 1 mark)

39.	What does facilitated diffusion across a cell membrane require?

	A pore protein	ATP	A concentration gradient	
A.	yes	no	no	
B.	no	no	yes	
C.	yes	no	yes	
D.	no	yes	no	
(Total 1 mark)

40.	The graph below represents the amount of DNA during the cell cycle. Which part of the graph represents metaphase?

(Total 1 mark)

41.	The following sequence of pictures, made using an electronic imaging technique, shows a cell undergoing division.

	[Adapted by permission from Macmillan Publishers Ltd, Fuller, B G et al. 2008. “Midzone activation of aurora B in anaphase produces an intracellular phosphorylation gradient”. Nature. Vol 453.]

(a)	State the stage of mitosis typified by image II.
......................................................................................................................................
(1)
 
(b)	List two processes that involve mitosis.
......................................................................................................................................
......................................................................................................................................
(2)
 
(c)	State the process that results in tumour (cancer) formation or development.
......................................................................................................................................
(1)
 
(d)	Explain, using one example, how non-disjunction in meiosis can lead to changes in chromosome number.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 6 marks)

42.	When observing the behaviour of a vesicle in a cell, what identifies it as a vesicle only involved in exocytosis?
A.	Adhesion between two lipid bilayers
B.	Fusion of two membranes
C.	Secretion of material
D.	Invagination of a plasma membrane
(Total 1 mark)

43.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled diagram of the ultrastructure of Escherichia coli as an example of a prokaryote.
(4)
 
(b)	Describe the events that occur in the four phases of mitosis in animals.
(6)
 
(c)	Explain the process of aerobic cell respiration after glycolysis has occurred.
(8)
(Total 20 marks)

44.	How does the surface area to volume ratio change with an increase in cell size?

(Total 1 mark)

45.	How do prokaryotic cells divide?
A.	By mitosis
B.	By meiosis
C.	By budding
D.	By binary fission
(Total 1 mark)

46.	What can the extracellular matrix of cells be made of?
I.	Polysaccharide
II.	Glycoprotein
III.	Phospholipid
A.	I only
B.	I and II only
C.	II and III only
D.	I, II and III
(Total 1 mark)

47.	During which phase of the cell cycle do chromosomes duplicate?
A.	G1
B.	S
C.	G2
D.	Mitosis
(Total 1 mark)

48.	What is the difference between simple diffusion and facilitated diffusion?

	Simple diffusion	Facilitated diffusion	
A.	Rate decreases with increasing concentration gradient	Rate increases with increasing concentration gradient	
B.	Faster movement of molecules	Slower movement of molecules	
C.	Always involves a membrane	Never involves a membrane	
D.	Uses any part of a membrane	Uses channels in the membrane	
(Total 1 mark)

49.	Which of these processes require mitosis?
A.	Embryological development
B.	Reducing surface area to volume ratio
C.	Maintaining cell size
D.	Cell growth
(Total 1 mark)

50.	Which of the following structures are found in all cells?
A.	Mitochondria
B.	Cell walls
C.	Chloroplasts
D.	Ribosomes
(Total 1 mark)

51.	By what process do most bacteria divide?
A.	Mitosis
B.	Meiosis
C.	Conjugation
D.	Binary fission
(Total 1 mark)

52.	Below is a micrograph of an E. coli bacterium undergoing reproduction.
		
[Source: www.bio.mtu.edu/campbell/prokaryo.htm]
	The scale bar represents 0.5 μm. How long are both cells in total?
A.	5.0 × 10–6 m
B.	5.0 × 10–9 m
C.	2.5 × 10–6 m
D.	2.5 × 10–9 m
(Total 1 mark)

53.	Below is a micrograph of an E. coli bacterium undergoing reproduction.
		
[Source: www.bio.mtu.edu/campbell/prokaryo.htm]
	In the diagram what does label X identify?
A.	Nucleoid region
B.	Chromatin
C.	Histones
D.	Endoplasmic reticulum
(Total 1 mark)

54.	The diagram below shows a plasma membrane. What is molecule X?
		
A.	Cholesterol
B.	Peripheral protein
C.	Glycoprotein
D.	Polar amino acid
(Total 1 mark)

55.	What is a difference between a cell in the G1 phase and a cell in the G2 phase of the cell cycle?
A.	A cell in the G2 phase would be smaller than a cell in the G1 phase.
B.	A cell in the G2 phase would have more mitochondria than a cell in the G1 phase.
C.	A cell in the G1 phase would have more DNA in its chromosomes than a cell in the G2 phase.
D.	DNA replication occurs in the G1 phase but not in the G2 phase.
(Total 1 mark)

56.	The electron micrograph below shows an E. coli cell.
		
[Source: www.microbiology.umaryland.edu/images/bact_em.jpg]
 
(a)	Identify the structures labelled A and B in the electron micrograph above and state one function of each.
A:	Name	.......................................................................................................
Function	.......................................................................................................
B:	Name	.......................................................................................................
Function	.......................................................................................................
(2)

(b)	Compare prokaryotic and eukaryotic cells.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
(Total 5 marks)

57.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled diagram to show the structure of a membrane.
(5)
 
(b)	Outline how vesicles are used to transport materials secreted by a cell.
(6)
 
(c)	Explain how the structure of a villus in the small intestine is related to its function.
(7)
(Total 20 marks)

58.	(a)	State the property of stem cells that makes them useful in medical treatment.
......................................................................................................................................
......................................................................................................................................
(1)
 
(b)	Explain how multicellular organisms develop specialized tissues.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)

(c)	Outline some of the outcomes of the sequencing of the human genome.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
(Total 6 marks)

59.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled diagram showing the ultrastructure of a typical prokaryote.
(4)
(b)	Outline how three different environmental conditions can affect the rate of photosynthesis in plants.
(6)
(c)	Explain how the emission of gases, both naturally and through human activity, can alter the surface temperature of the Earth.
(8)
(Total 20 marks)

60.	Which of the following is not a function performed by a membrane protein?
A.	Hormone binding sites
B.	Cell adhesion
C.	Enzyme synthesis
D.	Pumps for active transport
(Total 1 mark)

61.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled diagram showing the ultra-structure of a liver cell.
(4)
(b)	Distinguish between prokaryotic cells and eukaryotic cells.
(6)
(c)	Explain prokaryotic DNA replication.
(8)
(Total 20 marks)

62.	If a Sequoia sempervirens tree is 100 m tall and a drawing of it is 100 mm tall, what is the magnification of the drawing?
A.	×0.001
B.	×0.1
C.	×1.0
D.	×1000
(Total 1 mark)

63.	Which of the following structures does Escherichia coli have?
I.	70S Ribosomes
II.	Pili
III.	Nucleus
A.	I only
B.	I and II only
C.	II and III only
D.	I, II and III
(Total 1 mark)

64.	What feature do plant cells have but not animal cells?
A.	Plasma membranes
B.	Mitochondria
C.	Cell walls
D.	80S ribosomes
(Total 1 mark)

65.	Cells in the adrenal gland produce the hormone epinephrine and store it in vesicles. To release epinephrine these vesicles are carried to the plasma membrane and fuse with it. What process is occurring?
A.	Expulsion
B.	Exchange
C.	Excretion
D.	Exocytosis
(Total 1 mark)

66.	During reproduction in flowering plants an embryo sac is produced, containing one haploid nucleus.
This haploid nucleus divides by mitosis three times. What is produced?
A.	One diploid nucleus
B.	Four diploid nuclei
C.	Four haploid nuclei
D.	Eight haploid nuclei
(Total 1 mark)

67.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled diagram to show the fluid mosaic structure of a plasma membrane, indicating the hydrophilic and hydrophobic regions.
(5)
 
(b)	Distinguish between active and passive movements of materials across plasma membranes, using named examples.
(4)
 
(c)	Explain how the properties of water are significant to living organisms.
(9)
(Total 20 marks)

68.	What does therapeutic cloning involve?
A.	Developing genetically identical cultures of human cells for use in drug testing
B.	Helping infertile couples to conceive by injecting the father’s sperm into the mother’s egg
C.	Producing embryonic stem cells for medical use
D.	Replacing a mutant allele in an embryo to prevent genetic disease
(Total 1 mark)

69.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled diagram to show the ultrastructure of Escherichia coli.
(5)
 
(b)	Distinguish between active and passive movements of materials across plasma membranes, using named examples.
(4)
 
(c)	Explain how chemiosmosis assists in ATP production during oxidative phosphorylation.
(9)
(Total 20 marks)

70.	What is the correct order of increasing size for the following biological structures?
I.	The width of a virus
II.	The width of a bacterium
III.	The thickness of a cell surface membrane
IV.	The diameter of a eukaryotic cell
A.	I ® III ® II ® IV
B.	I ® III ® IV ® II
C.	III ® I ® II ® IV
D.	III ® II ® I ® IV
(Total 1 mark)

71.	Which of the following structures are present in both plant and animal cells?
I.	Cell wall
II.	Chloroplast
III.	Mitochondrion
A.	I only
B.	I and II only
C.	I and III only
D.	III only
(Total 1 mark)

72.	In viewing an electron micrograph of a cell, ribosomes, pili and a single circular chromosome are observed. What other structure is likely to be present?
A.	The rough endoplasmic reticulum (rER)
B.	Mitochondria
C.	A nuclear membrane
D.	A plasmid
(Total 1 mark)

73.	The DNA of a particular cell is damaged, so that the cell continues to divide uncontrollably. What is the possible result?
A.	Coronary heart disease
B.	AIDS
C.	Tumour formation
D.	Down syndrome
(Total 1 mark)

74.	What is produced as a result of mitosis?
A.	Two cells, each containing half the number of chromosomes of the original cell
B.	Two cells, each containing the same number of chromosomes as the original cell
C.	Four cells, each containing the same number of chromosomes as the original cell
D.	Four cells, each containing half the number of chromosomes of the original cell
(Total 1 mark)

75.	(a)	Define osmosis.
.....................................................................................................................................
.....................................................................................................................................
(1)
 
(b)	Outline how transport occurs across membranes by facilitated diffusion.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)

(c)	Explain how the properties of phospholipids help to maintain the structure of cell membranes.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 6 marks)

76.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw and label a diagram of the ultrastructure of a liver cell.
(4)
(b)	Explain how mitosis produces two genetically identical nuclei.
(8)
(c)	Outline one therapeutic use of stem cells.
(6)
(Total 20 marks)

77.	Which of the following is a feature of exocytosis but not endocytosis?
A.	Shape changes of a membrane
B.	Vesicle formation
C.	Use of ATP
D.	Secretion
(Total 1 mark)

78.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw a labelled diagram showing the structure of a plasma membrane.
(4)
(b)	Outline the role of chlorophyll and the effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis.
(6)
(c)	Explain the production of energy during aerobic respiration from pyruvate that has been produced by glycolysis.
(8)
(Total 20 marks)