1.	The diagram below shows possible pathways for the breakdown of glucose in various cells.

(a)	State the names of processes Q and R.
Q:	...........................................................................................................................
(1)
R:	...........................................................................................................................
(1)
 
(b)	Deduce the names of substances A and D.
A:	...........................................................................................................................
(1)
D:	...........................................................................................................................
(1)
 
(c)	State the organelle in which process R takes place.
.....................................................................................................................................
(1)
(Total 5 marks)

2.	At the start of glycolysis, glucose is phosphorylated to produce glucose 6-phosphate, which is converted into fructose 6-phosphate. A second phosphorylation reaction is then carried out, in which fructose 6-phosphate is converted into fructose 1,6-bisphosphate. This reaction is catalyzed by the enzyme phosphofructokinase. Biochemists measured the enzyme activity of phosphofructokinase (the rate at which it catalyzed the reaction) at different concentrations of fructose 6-phosphate. The enzyme activity was measured with a low concentration of ATP and a high concentration of ATP in the reaction mixture. The graph below shows the results.

(a)	(i)	Using only the data in the above graph, outline the effect of increasing fructose 6-phosphate concentration on the activity of phosphofructokinase, at a low ATP concentration.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(ii)	Explain how increases in fructose 6-phosphate concentration affect the activity of the enzyme.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(b)	(i)	Outline the effect of increasing the ATP concentration on the activity of phosphofructokinase.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(ii)	Suggest an advantage to living organisms of the effect of ATP on phosphofructokinase.
...........................................................................................................................
...........................................................................................................................
(1)
(Total 7 marks)

3.	Explain the similarities and differences in anaerobic and aerobic cellular respiration.
(Total 8 marks)

4.	The rate of carbon dioxide uptake by the green succulent shrub Aeonium goochiae can indicate the amount of photosynthesis taking place in the plant. This rate was measured at 15°C and 30°C over a 24-hour period. The units of carbon dioxide absorption are mg CO2 h–1.
	The results are shown below. The centre of the graph corresponds to –2 mg CO2 h–1 and the outer ring is +2.5 mg CO2 h–1.

[Source: adapted from www.biologie.uni-hamburg.de/b-online/e24/9.htm]
 
(a)	Identify a time that carbon dioxide uptake was the same at both temperatures.
.....................................................................................................................................
(1)
 
(b)	State the maximum rate of carbon dioxide uptake at 15°C.
.....................................................................................................................................
(1)

(c)	Compare the rate of carbon dioxide uptake at each temperature in daylight and darkness.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
 
(d)	Suggest why the carbon dioxide uptake may at times be negative.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 6 marks)

5.	(a)	(i)	Identify the cell organelle shown in the micrograph below.

...........................................................................................................................
(1)

(ii)	Identify the structure labelled I above and explain how it is adapted for the organelle to function efficiently.
...........................................................................................................................
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...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
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(3)
 
(b)	Describe the role of acetyl CoA in the metabolism of lipids.
.....................................................................................................................................
.....................................................................................................................................
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.....................................................................................................................................
(2)
(Total 6 marks)

6.	Anaerobic respiration occurs in the absence of oxygen while aerobic respiration requires oxygen.
(a)	State one final product of anaerobic respiration.
.....................................................................................................................................
(1)

(b)	Complete the table showing the differences between oxidation and reduction.
	Oxidation	Reduction	
Electrons gained or
lost			
Oxygen or hydrogen gained or lost			
(2)
 
(c)	The structure of a mitochondrion is shown in the electron micrograph below.

	Name the parts labelled A, B and C and state the function of each.
Part A:	Name: ..........................................................................................................
	Function: ......................................................................................................
Part B:	Name: ...........................................................................................................
	Function: ......................................................................................................
Part C:	Name: ...........................................................................................................
	Function: ......................................................................................................
(3)
(Total 6 marks)

7.	Biosphere 2, an enormous greenhouse built in the Arizona desert in the USA, has been used to study five different ecosystems. It is a closed system so measurements can be made under controlled conditions. The effects of different factors, including changes in carbon dioxide concentration in the greenhouse, were studied. The data shown below were collected over the course of one day in January 1996.

[Source: http://www.Ideo.columbia.edu/martins/climate_water/labs/lab6/labinstr6/html]
 
(a)	(i)	Identify the time of day when the sun rose.
...........................................................................................................................
(1)
 
(ii)	Identify the time of minimal CO2 concentration.
...........................................................................................................................
(1)
 
(b)	Determine the maximum difference in the concentration of CO2 over the 24-hour period.
.....................................................................................................................................
.....................................................................................................................................
(1)

(c)	Suggest reasons for changes in CO2 concentration during the 24-hour period.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 5 marks)

8.	(a)	State two functions of proteins with a named example of each.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
 
(b)	Explain chemiosmosis as it occurs during cell respiration.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)

9.	The respiratory quotient (RQ) is a measure of the metabolic activity of an animal. It is the ratio of CO2 produced to O2 consumed. In general, the lower the RQ value the higher the energy yield. The RQ is dependent on the diet consumed by the animal. The following table lists the typical RQ values for specified diets.
Diet	RQ	
Lipid	0.71	
Carbohydrate	1.00	
Protein	0.74	
[Source: Walsberg and Wolf, Journal of Experimental Biology, (1995), 198, pages 213–219.
Reproduced by permission of The Company of Biologists Ltd]
	In an experiment to assess RQ values for house sparrows, the birds were fed a diet of pure mealworms (beetle larvae) or millet (a type of grain).
 
	The graph below shows the RQ values of a house sparrow fed on a high carbohydrate diet (millet) and a high lipid diet (mealworms).

[Source: Walsberg and Wolf, Journal of Experimental Biology, (1995), 198, pages 213–219.
Reproduced by permission of The Company of Biologists Ltd]

(a)	Compare the RQ values for millet and mealworms between 1 hour and 6 hours after feeding.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
 
	The expected RQ value for house sparrows metabolizing millet is 0.93. The expected value when metabolizing mealworms is 0.75.
 
(b)	Explain why the expected RQ values for millet and mealworms are different.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
 
(c)	Suggest reasons for
(i)	the high initial RQ values for house sparrows fed on millet;
...........................................................................................................................
...........................................................................................................................
(1)

(ii)	the rapid fall in RQ values for house sparrows fed on millet.
...........................................................................................................................
...........................................................................................................................
(1)
(Total 6 marks)

10.	(a)	State two products of the process of glycolysis.
.....................................................................................................................................
.....................................................................................................................................
(1)
 
(b)	Explain the significance of polar and non-polar amino acids within the cell.
.....................................................................................................................................
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(3)
(Total 4 marks)

11.	Aerobic respiration involves conversion of glucose into pyruvate and conversion of pyruvate into carbon dioxide and water. Where do these processes occur in a eukaryotic cell?
	Where glucose is broken down
into pyruvate	Where pyruvate is broken down
into carbon dioxide and water	
A.	Cytoplasm	Cytoplasm	
B.	Cytoplasm	Mitochondrion	
C.	Mitochondrion	Cytoplasm	
D.	Mitochondrion	Mitochondrion	
(Total 1 mark)

12.	The diagram below shows some features of ATP synthetase.
(a)	Identify in which cell organelle the process below occurs?
....................................................................................................................................

(1)

(b)	Explain the process represented by the diagram.
....................................................................................................................................
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....................................................................................................................................
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(3)
(Total 4 marks)

13.	The electron micrographs below show mitochondria in longitudinal section. The mitochondrion in A is from a bat pancreas cell and that in B is from a mouse liver cell.

[Source: Tribe and Whittaker, Chloroplasts and Mitochondria, (1972), 31, pp 28–29]

(a)	Annotate the micrographs to show two similarities in the structure of the mitochondria.
(2)
 
(b)	The mitochondria differ in size. State two other differences that are visible in the mitochondria.
1.	..........................................................................................................................
2.	..........................................................................................................................
(2)
 
(c)	Predict, with two reasons, which of the mitochondria would have been able to produce ATP at a greater rate.
....................................................................................................................................
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(3)
(Total 7 marks)

14.	Magellanic penguins (Spheniscus magellanicus) live and breed near the coast of Argentina. However, their colonies are a long way from the open sea where they hunt for fish. They cannot fly so have to swim to the feeding grounds. A study investigated how the water currents due to high and low tides affected their journey to and from their colonies. The results are shown below.

[Source: R. P. Wilson, “Magellanic Penguins Spheniscus magellanicus commuting through San Julian Bay;
do current trends induce tidal tactics?”, Journal of Avian Biology (Oct 30 2003), vol. 32, issue 1, pp. 83-89.
Copyright © 2003. Reprinted with permission of Blackwell Publishing Ltd.]
 
(a)	(i)	Identify the number of penguins departing from the colony at 06:00 hours.
..........................................................................................................................
(1)
 
(ii)	Identify the time of day when most penguins arrive at the colony.
..........................................................................................................................
(1)

(b)	Describe the pattern of movement of penguins departing from the colony between 06:00 hours and 22:00 hours.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
 
(c)	Suggest why there is little movement in either direction between 14:00 hours and 16:00 hours.
....................................................................................................................................
....................................................................................................................................
(2)
 
The study also investigated the range of swim speed for one penguin when out hunting in the open sea.

[Source: R. P. Wilson, “Magellanic Penguins Spheniscus magellanicus commuting through San Julian Bay; do current trends induce tidal tactics?”, Journal of Avian Biology (Oct 30 2003), vol. 32, issue 1, pp. 83-89. Copyright © 2003. Reprinted with permission of Blackwell Publishing Ltd.]
 
(d)	Calculate the greatest difference in swim speed during the study.
....................................................................................................................................
....................................................................................................................................
(1)
 
(e)	Suggest two reasons for the changes in swim speed of the penguin during the period of time of the study.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
 
The diagram below shows part of the coastline.

[Source: R. P. Wilson, “Magellanic Penguins Spheniscus magellanicus commuting through San Julian Bay; do current trends induce tidal tactics?”, Journal of Avian Biology (Oct 30 2003), vol. 32, issue 1, pp. 83-89. Copyright © 2003. Reprinted with permission of Blackwell Publishing Ltd.]
 
(f)	A penguin uses 88 joules of energy to walk one metre. Calculate the energy used to walk from point X to point Y.
....................................................................................................................................
....................................................................................................................................
(1)
 
(g)	The penguin uses more energy swimming. Suggest one reason why most penguins actually swim rather than walk from point X to point Y.
....................................................................................................................................
....................................................................................................................................
(1)
 
(h)	Explain why penguins have many mitochondria in the muscles used for swimming.
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(2)
(Total 13 marks)

15.	Up to two additional marks are available for the construction of your answers.
(2)
	(a)	Draw and label a diagram to illustrate the fluid mosaic model of biological membranes.
(5)
(b)	Using a table, compare aerobic and anaerobic respiration in a eukaryotic cell.
(5)
(c)	Explain the process of translation.
(8)
(Total 20 marks)

16.	(a)	State the net gain of ATP molecules during glycolysis of one glucose molecule.
....................................................................................................................................
(1)
 
(b)	State where in the mitochondrion the enzymes of the Krebs cycle are found.
....................................................................................................................................
(1)
 
(c)	Compare the process of chemiosmosis in both respiration and photosynthesis.
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(3)
(Total 5 marks)

17.	Which row in the table describes the first stage of cellular respiration?
	Substrate	Location	Product	Product	
A.	pyruvate	mitochondria	oxygen	water	
B.	pyruvate	cytoplasm	carbon dioxide	ATP	
C.	glucose	mitochondria	pyruvate	water	
D.	glucose	cytoplasm	pyruvate	ATP	

(Total 1 mark)

18.	The mitochondrion carries out key reactions in the cells of eukaryotes.

[Source: D S Friend, Brigham and Women’s Hospital, www.nigms.nih.gov/ news/science_ed/mito1.html]

(a)	(i)	State the name of label A and label B in the photomicrograph above.
A:	...............................................................................................................
B:	...............................................................................................................
(1)
 
(ii)	State the processes that occur at label A and label B.
A:	...............................................................................................................
B:	...............................................................................................................
(1)

(b)	Explain the relationship between the structure of the mitochondrion and its function.
...................................................................................................................................
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(3)
(Total 5 marks)

19.	The eastern oyster (Crassostrea virginica) is a marine mollusc that lives in estuaries. The environmental surroundings of the eastern oyster, such as the temperature and concentration of trace elements, are constantly changing. The trace element cadmium affects the mitochondria and prevents them from carrying out their function efficiently. Investigators isolated mitochondria from the oysters to study how the respiration rate changed while varying the water temperature and the cadmium ion concentration.

[Source: I M Sokolova, (2004), The Journal of Experimental Biology, 207, pages 2639–2648.
With permission of the Company of Biologists Ltd.]

(a)	State the relationship between the concentration of cadmium ions and respiration rate at 35°C.
.....................................................................................................................................
.....................................................................................................................................
(1)
 
(b)	Compare the respiration rate of the mitochondria at cadmium ion concentrations of 0mmol dm–3 and 50mmol dm–3.
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(2)
 
(c)	Suggest one other environmental property of the water, apart from temperature and mineral concentration, that may show daily changes.
.....................................................................................................................................
(1)
 
(d)	The investigators concluded that seasonal and global warming might make the eastern oysters more likely to suffer from trace element poisoning.
Using the data, evaluate this hypothesis.
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(3)
(Total 7 marks)

20.	What is the correct sequence of chemicals produced in the anaerobic respiration pathway?
A.	Lactate → pyruvate → ethanol
B.	Ethanol → pyruvate → glucose
C.	Glucose → lactate → pyruvate
D.	Glucose → pyruvate → lactate
(Total 1 mark)

21.	Where in eukaryotic cells is glucose broken into pyruvate, to release energy for use in the cell?
A.	Chloroplast
B.	Cytoplasm
C.	Mitochondrion
D.	Nucleus
(Total 1 mark)

22.	(a)	Explain the properties of water that allow living organisms to use it as a habitat.
.....................................................................................................................................
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(3)
 
(b)	List two end products of aerobic cell respiration.
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(2)

(c)	State the name of the molecule that is the source of the oxygen released by plants during photosynthesis.
.....................................................................................................................................
(1)
(Total 6 marks)

23.	Mitochondrial electron transport defects (called mitochondrial myopathy) causes tiredness at low levels of exercise and varies from mild to severe. Scientists measured oxygen delivery to cells and oxygen use in cells of thirty-five patients with mitochondrial myopathy. The results were compared to a control group of thirty-two healthy individuals. The results are shown in the two charts below.

[Source: adapted from T. Taivassalo and R. G. Haller, (2006), ‘Exercise and training in mitochondrial myopathies’,
Medicine and Science in Sports and Exercise, 37 (12) 2094-2101, © Lippincott Williams & Wilkins, USA]
 
(a)	State the mean value for oxygen delivery to cells in patients suffering from mitochondrial myopathy.
......................................................................................................................................
(1)

(b)	Calculate the percentage difference of the oxygen use in cells by the control group compared to oxygen use in cells of patients with mitochondrial myopathy.
................ %
(1)
 
(c)	Discuss why people with mitochondrial myopathy tire more easily than healthy individuals.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
(Total 5 marks)
 
24.	Fruits remain alive for a period of time after harvesting. Cellular respiration continues and it can greatly influence the maturation (ripening) process in the fruits. The rate of respiration depends on many factors such as the type, quality, degree of ripeness and water content of the fruits, temperature and air composition. Respiration that continues after harvesting may sometimes lead to the over-ripening and eventual loss of an entire cargo of fruit during transport.
	Studies of the maturation process in bananas are summarized in the following graph.

[Source: www.containerhandbuch.de/chb_e/scha/index.html?/chb_e/scha/scha_15_02_03_02.html]

(a)	(i)	State two chemical products released as gases during cellular respiration.
1 ........................................................................................................................
2 ........................................................................................................................
(1)
(ii)	State one non-chemical product of respiration.
...........................................................................................................................
(1)
 
(b)	Using the data, analyse the events that occur when maturation begins in bananas.
.....................................................................................................................................
.....................................................................................................................................
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(2)
 
(c)	Suggest, giving reasons, two ways in which transport conditions can be controlled to minimize over-ripening.
.....................................................................................................................................
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(2)
(Total 6 marks)

25.	(a)	Compare the structure of a mitochondrion with a chloroplast.
Mitochondrion	Chloroplast	
.............................................................
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(3)
 
(b)	Explain the role of chemiosmosis in oxidative phosphorylation.
.....................................................................................................................................
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.....................................................................................................................................
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.....................................................................................................................................
(3)
(Total 6 marks)

26.	Humans can respire aerobically and anaerobically. Which are products of both aerobic cell respiration and anaerobic cell respiration in humans?
A.	Pyruvate and ATP
B.	Pyruvate and lactate
C.	ATP and carbon dioxide
D.	Lactate and carbon dioxide
(Total 1 mark)

1.	(a)	Q: anaerobic respiration / fermentation;
R: aerobic respiration / Kreb’s (citric acid) cycle;	2
 
(b)	A: pyruvate / 3-oxopropanoate;
D: carbon dioxide;	2
 
(c)	mitochondrion;	1
[5]

2.	(a)	(i)	increasing fructose 6-phosphate concentration (initially) causes an increase
in activity;
activity levels out / remains constant as (substrate) concentration continues 
to rise;	2
(ii)	more collisions with active site as concentration rises;
at high substrate levels all active sites are occupied so no further increase 
in rate / enzyme working at maximum rate;	2
 
(b)	(i)	decreases activity;
at all fructose 6-phosphate concentrations;
most effect at intermediate fructose 6-phosphate concentrations / little difference
at high fructose 6-phosphate concentrations;
ATP acts as an inhibitor;	2 max
 
(ii)	end-product inhibition;
respiration rate decreased if ATP already available;	1 max
[7]

3.	Answers must include both similarities and differences to receive full marks.
aerobic requires oxygen and anaerobic does not utilize oxygen;
	similarities: 	3 max
both can start with glucose;
both use glycolysis;
both produce ATP / energy (heat);
both produce pyruvate;
carbon dioxide is produced;
(both start with glycolysis) aerobic leads to Krebs’ cycle and anaerobic
leads to fermentation;
 
	differences: 	5 max
anaerobic:
(fermentation) produces lactic acid in humans;
(fermentation) produces ethanol and CO2 in yeast;
occurs in cytoplasm of the cell;
recycles NADH (NAD+);
 
	aerobic cellular respiration:
pyruvate transported to mitochondria;
further oxidized to CO2 and water (in Krebs’ cycle);
produce a larger amount of ATP (36–38 ATP) / anaerobic produces less ATP (2);
can use other compounds / lipids / amino acids for energy;
[8]

4.	(a)	06:00 / 19:30 to 19:45	1
Accept 6 am / 7:30 pm to 7:45 pm.
 
(b)	23 mg CO2 h–l (±0.1) (units required)	1
 
(c)	more uptake at 15°C than 30°C during the hours of daylight;
both are high during the hours of daylight / reverse argument;
greater uptake at 30°C than 15°C during the hours of darkness;
at only 15°C uptake become negative;	3 max
 
(d)	respiration rate greater than photosynthesis (during the hours of darkness)	1
[6]

5.	(a)	(i)	mitochondrion	1
(ii)	crista;
	Award [1] for each of the following, up to [2 max].
	folded membrane;
provides large surface area;
for electron transport chain / site of ATP synthesis;
moves protons to inter membrane space from matrix;	3 max
 
(b)	fatty acids oxidized / broken down;
form two-carbon atom (acetyl) fragments;
which are passed to Krebs’ cycle to be metabolized;	2 max
[6]

6.	(a)	ATP;
CO2;
ethanol;
lactic acid;
heat energy;	1
 
(b)
Reaction	Oxidation	Reduction	
Electrons gained or lost	loss of electrons	gain of electrons;	
Oxygen or hydrogen gained or lost	gain of oxygen / 
loss of H+ / hydrogen	loss of oxygen / 
gain of H+ / hydrogen;	
Award [2] for four correct and [1] for two correct.	2
 
(c)	A – matrix: site for Krebs’ cycle / link reaction / ATP synthesis;
B – inner membrane / cristae: site of oxidative phosphorylation / e– transport 
chain / increase surface area / ATP synthesis;
C – inter membrane : H+ / proton build up;
or
C – outer membrane: determines which substances enter the mitochondrion;	3 max
Award [1 max] if only the three labels are given.
[6]

7.	(a)	(i)	07:30 / 7.30 am / 7.5 hours (accept answers in range up to 07.45)	1
(ii)	17:00 / 5.00 pm (± ½ hour)	1

(b)	250 ppm (± 30 ppm) (unit required)	1
 
(c)	at night / darkness / no light only respiration occurs so CO2 increases;
in day / with light both respiration and photosynthesis occur / photosynthesis 
exceeds respiration in day;
CO2 is used by photosynthesis and level decreases;
when sun sets, CO2 again increases as only respiration occurs;	2 max
[5]

8.	(a)	Award [1] for any two correct examples.
hormones eg insulin;
enzymes eg amylase;
structural eg collagen;
movement eg myosin / actin;
transport eg hemoglobin;
defence eg antibodies / immunoglobin;	2 max
 
(b)	ATP synthesis is coupled to electron transport / H+ movement;
occurs over the (inner) mitochondrial membrane;
electrons are transported through carriers;
energy released by electron transport;
protons / H+ pumped across the membrane;
ATP synthetase transports H+;
uses energy to make ATP;	2 max
[4]

9.	(a)	between 1.5 and 3.5 hours (or number between these figures)
after feeding mealworm RQ values are higher than for millet;
no difference in RQ values between 3.5 hours and 6 hours;
between 0.5 and 1.5 hours (or number between these figures)
millet RQ values much higher than for mealworm;
between 2 and 3 hours mealworm RQ values are
slightly higher than for millet;	2 max
 
(b)	millet is not composed entirely of carbohydrates;
millet contains more carbohydrates;
mealworms contain more lipids / proteins;	2 max

(c)	(i)	using carbohydrate (from millet as a respiratory substrate)	1 
(ii)	reverting to other substrates / 
carbohydrates (from millet) used up	1
[6]

10.	(a)	Award [1] for any two products.
ATP;
NADH;
pyruvate;	1 max
 
(b)	polar amino acids are hydrophilic and non-polar amino acids
are hydrophobic;
position of polar and non-polar amino acids determine
protein shape / function / location;
(in channel proteins) hydrophilic amino acids line the
channels and allow transport of ions / polar substances;
non-polar amino acids are in contact / embedded
within the lipid membrane;
polar amino acids on the surface proteins make
them water soluble;
non-polar in the centre of water-soluble proteins
stabilize the structure;	3 max
Accept any of the above points if clearly explained using a suitably labelled diagram.
[4]

11.	B
[1]

12.	(a)	mitochondria	1 max
 
(b)	shows membrane of a mitochondrion / chloroplast;
H+ is pumped out across membrane;
more H+ outside (from electron transport chain);
concentration gradient of H+ is formed / potential energy;
	H+ movement across membrane through protein channels in ATP
synthetase;
ADP is phosphorylated / picks up phosphate to ATP;
ATP has more energy than ADP;
chemiosmosis;	3 max
[4]

13.	(a)	both have two (outer) membranes;
both have cristae;
both have a matrix (with a grainy appearance) / ribosomes;	2 max
 
(b)	shape;
arrangement of cristae;
density of cristae;
	amount of matrix granules / any reference to dark dots;
(do not accept ribosomes)	2 max
 
(c)	A / bat’s;
larger size / volume;
greater surface area of cristae / more cristae;
closeness of mitochondria in B mouse reduces rate;	3 max
[7]

14.	(a)	(i)	48 (±1)	1
(ii)	22:00 hours (evening) / 10 pm (units required)	1
 
(b)	greatest number leaving in early morning / 6:00 hours / 6 am;
	reduces during midday / early afternoon / general decline from 6:00-16:00
hours / 6 am-4 pm;
	increases slightly in evening / after 18:00 hours / 6 pm / 18:00-20:00
hours / 6 pm-10 pm;	2 max
 
(c)	(strongest) current to colony (so difficult to leave);
current brings in food;
	long way to feeding grounds / long time feeding;
all / many out at sea hunting;
penguins resting;	2 max
 
(d)	(3.75ms-1 - 1.0) = 2.75(±0.50) ms−1 (units required)	1
 
(e)	slow / uniform (with some peaks) when looking for prey / fish;
(faster when) chasing / catching prey / fish;
(slow in) moments of rest;
(faster when) escaping predators;	2 max
 
(f)	15 400 joules / J / 15.4 kilojoules / kJ (units required)	1

(g)	can escape faster from predators in sea;
avoid human activity on land;
body more adapted to swimming / less adapted to walking;
Accept any valid adaptation looking for concept not necessarily term.
temperature on land could be more extreme;
may feed while swimming;	1 max
Do not accept "faster to swim" unless qualified with valid reason.
 
(h)	mitochondria provide ATP (from aerobic respiration);
(swimming) muscles require a lot of energy;	2
[13]

15.	(a)	Award [1] for any of the following clearly drawn and correctly labelled.
phospholipids (bilayer);
hydrophilic heads and hydrophobic tails;
intrinsic / integral proteins / protein channels;
glycoproteins / receptor proteins / glycolipids on outside;
cholesterol embedded in membrane;
extrinsic / peripheral proteins;
thickness size 10 nm (0.1 μm);	5 max
 
(b)	Award [1] for each correct row, up to [5 max].
Aerobic respiration	Anaerobic respiration	
occurs in mitochondria	occurs in cytoplasm;	
requires O2	occurs without O2;	
both produce pyruvate from glucose (glycolysis);	
uses fatty acids / lipids / amino acids	doesn’t use fatty acids;	
(Krebs cycle) produces CO2 and H2O	(fermentation) produces ethanol / CO2
(in yeast);	
(Krebs cycle) produces CO2 and H2O	(fermentation) produces lactate in
animals (humans);	
NADH produced in both;	
large amount of ATP (36 per glucose
molecule) produced	small amount of ATP (2 per glucose
molecule) produced;	
		5 max

(c)	messenger / mRNA attaches to ribosome (small unit);
many ribosome / polyribosomes bind to same mRNA;
carries codons / triplet of bases each coding for one amino acid;
transfer / tRNA each have specific anticodon;
triplet of bases for specific amino acid;
tRNA carries specific amino acid;
tRNA binds to ribosomes;
to corresponding triplet base / codon;
a second tRNA binds to next codon;
two amino acids bind together;
in a peptide linkage;
first tRNA detaches;
ribosome moves along mRNA;
another tRNA binds to next codon;
continues until polypeptide / protein formed to stop codon;
	stop codon has no corresponding tRNA / amino acid / causes release
of polypeptide;	8 max
 
(Plus up to [2] for quality)
[20]

16.	(a)	2	1
 
(b)	matrix (fluid)	1
 
(c)	Award [1] for each row, up to [3 max].
Respiration	Photosynthesis	
both make ATP;	
both involve electron transport;	
protons move against a concentration gradient in both;	
both require ATP synthetase;	
occurs in mitochondrion	occurs in chloroplasts / thylakoids;	
uses energy from oxidation	uses energy from light;	
has NADH for electron production	has water for electron production;	
		3 max
[5]

17.	D
[1]

18.	(a)	(i)	A: cristae / inner membrane;
B: matrix;	1
Both needed for [1].
(ii)	A: electron transport / proton transport;
B: Krebs cycle / ATP synthesis;	1
Both needed for [1].
 
(b)	large surface area of cristae allows electron transport / oxidative phosphorylation
to be very efficient;
matrix provides necessary chemical environment for the Krebs cycle;
	small distance between inner and outer membranes allows rapid movement
of molecules between cytosol and matrix;
small space between membranes allows protons to be
accumulated / concentrated;	3 max
[5]

19.	(a)	as cadmium ion concentration increases, respiration rate decreases	1
 
(b)	at 50 mmol dm−3 respiration is lower than at 0 mmol dm−3 for all temperatures;
	at50 mmol dm−3 respiration is highest at 15°C, whereas at 0 mmol dm−3 respiration
is highest at 25°;
respiration at 35°C is lowest at both cadmium concentrations;	2 max
 
(c)	salinity / pH / clarity / oxygen level / pollution	1
 
(d)	data shows results only for cadmium, not for all trace elements;
	the hypothesis is always supported for changes of temperature from 15 / 25 to
35°C;
the hypothesis is not always supported from 15 to 25°C;
at 35°C the effect on respiration is greatest at all cadmium levels;
	may be other factors causing the respiration to fall (such as activity of
enzymes);
marine temperatures unlikely to reach 35°C;	3 max
[7]

20.	D
[1]

21.	B
[1]

22.	(a)	maximum density at 4°C so allows life beneath the ice;
hydrogen bonding between molecules / cohesion;
solvent for chemicals / reactions;
transparency allows light penetration (into cells / aquatic habitats);
high boiling point / rarely boils in natural habitats;
latent heat allows cooling / evaporation;
high heat capacity (important in maintaining constant temperature);
surface tension allows organisms to move on surface of rivers / 
lakes / pools;	3 max
 
(b)	water;
carbon dioxide;
ATP;	2 max
 
(c)	water	1
[6]

23.	(a)	210 ml kg–1 min–1 (±2) (units required)	1
 
(b)	Accept 86 (±2) or 46 (±2)	1
 
(c)	oxygen delivery is similar to healthy;
oxygen use is lower / half;
insufficient energy / ATP produced by aerobic respiration;
forced to respire anaerobically;
lactic acid builds up;	3 max
[5]

24.	(a)	(i)	carbon dioxide and water	1
Need both to receive the mark.
 
(ii)	heat / energy	1
 
(b)	starch is broken down transforming into sugar;
chlorophyll is broken down so bananas change from green to yellow;
increase in respiration causes water release and CO2 formation;	2 max
 
(c)	reduce heat of cargo / refrigerate (bananas) to slow respiration rate;
lower oxygen / raise nitrogen / carbon dioxide level in cargo
atmosphere to inhibit respiration rate;
shorten transport distance / time so less time to over ripen;	2 max
[6]

25.	(a)	Award [1] for each row of structural features.
mitochondrion	chloroplast	
both contain DNA and RNA;	
both contain ribosomes;	
both have double membranes;	
no pigments	contains pigments;	
matrix	stroma;	
inner membrane folded (cristae) / 
no thylakoids	no folds (cristae) / thylakoids;	
both have electron transport system	
does not have NADPH	has NADPH	
		3 max
 
(b)	ADP is phosphorylated to ATP through addition of inorganic phosphate;
by enzyme ATP synthetase / synthase;
when H+ ions (protons) diffuse;
through channels in ATP synthetase / synthase;
from high H+ concentration in mitochondrial intermembrane space;
to low H+ concentration in mitochondrial matrix;	3 max
[6]

26.	A
[1]