1.	The figure below shows the major bones of the front leg of a cheetah.

(i)	Name bones A to D.
A ..................................................................
B ..................................................................
C ..................................................................
D ..................................................................
[2]

(ii)	Joints X and Y are synovial joints. Describe the roles played by ligaments and cartilage in this type of joint.
ligaments ........................................................................................................
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cartilage ..........................................................................................................
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[4]
 
(iii)	The muscles that move the lower part of the front leg at joint Y are antagonistic.
	Describe how antagonistic muscles are used to move the lower arm of a human.
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[3]
[Total 9 marks]

2.	Calcium ions are necessary for the contraction of rabbit’s striated muscle.
	Describe the role played by calcium ions in the contraction of striated muscle.
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[Total: 3 marks]

3.	The diagram below shows an artery lying on the surface of living heart muscle as seen by an instrument called an endoscope. The lumen of the artery has become narrowed at the point labelled Y.

The Forum on Ischaemic Heart Disease.
Reproduced by kind permission of Dr Graham Jackson,
Cardiology Unit, Guy’s and St Thomas’ Hospital.

(i)	Describe the effects that this narrowing of the artery is likely to have on the
heart muscle.
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[3]
 
(ii)	State two symptoms that might be shown by a person whose artery has been narrowed in this way.
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2 ......................................................................................................................
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[2]
[Total 5 marks]

4.	The figure below shows a section through a human elbow joint.

(i)	Name A and B.
A ..................................................................
B ..................................................................
[2]
 
(ii)	Describe the roles of A and B in the movement of the elbow joint.
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[3]
[Total 5 marks]

5.	In an investigation, striated muscle tissue from a mammal was electrically stimulated over a period of 700 milliseconds (ms). The tension generated by the muscle was measured during the investigation and the results are shown in the figure below.

From Nuffield Advanced Science Biology. Study Guide 1, adapted
from graph p. 349, published by Longman, 1985 (ISBN 0-582-35431-5)
(i)	Describe the relationship between muscle stimulation and muscle tension in region A on the figure.
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[2]

(ii)	Region B on the figure above shows the tension of the muscle with repeated stimulation. Some toxins, such as those released by the tetanus bacterium, also cause the effect shown in region B.
	Suggest why these toxins may be fatal.
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[3]
[Total 5 marks]

6.	In this question, one mark is available for the quality of use and organisation of scientific terms.
	The following figure shows a neuromuscular junction.

	The figure above shows that mitochondria are present on both sides of the synaptic cleft. Explain why mitochondria are essential for the transmission of impulses across the cleft and for muscular contraction.
transmission of impulses across the cleft .................................................................
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muscular contraction ................................................................................................
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[8]
Quality of Written Communication [1]
[Total 9 marks]

7.	When a book is held in the hand, as shown in Fig.1 A, there is a constant load. The muscles of the upper arm contract to produce a force that opposes the load, so maintaining the position of the hand.
	Muscle spindles are a type of stretch receptor, which detect changes in the length of muscles.
	When a second book is placed in the hand, as shown in Fig.1 B, the load increases. This stretches the muscle spindle resulting in an almost immediate increase in the contraction of the muscles of the upper arm, to maintain the position of the hand, as shown in the figure Fig.1 C.

	Name bone F.
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[Total 1 mark]

8.	Below is a drawing of the brain that shows the origin of the cranial nerves.

(a)	State the direction from which the brain has been drawn.
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[1]
 
(b)	(i)	Name the structures A, B, C and D shown on the diagram.
A .............................................................................................................
B .............................................................................................................
C .............................................................................................................
D .............................................................................................................
[4]

(ii)	State two roles of structure D.
1 .............................................................................................................
2 .............................................................................................................
[2]
 
(c)	The hypothalamus constantly monitors and regulates the concentration of hormones in the blood. Outline how the hypothalamus regulates the concentration of hormones in the blood.
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[2]
[Total 9 marks]

9.	A positron emission tomography (PET) scan can be used to investigate the activity of the brain. PET scans can help to diagnose conditions such as Alzheimer’s disease. A radioactive isotope is attached to molecules similar to glucose and injected into the blood supplying the brain. The molecules with the radioactive isotope are taken up by healthy cells, but are not metabolised. Instead they emit positrons, which can be detected by the PET scanner.
	The figure below shows PET scans of a normal brain and the brain of a person with Alzheimer’s disease.
•	Red and yellow indicate high emissions of positrons.
•	Blue and black indicate low emissions of positrons.

	With reference to the figure and the information above, explain the differences between the two PET scans.
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[Total: 3 marks]

10.	In this question, one mark is available for the quality of spelling, punctuation and grammar.
	The figure below shows the left side of the cerebrum of a human.

	A person is reading a book. Outline the events that take place in the nervous system from the time an image of a word is formed on the retina to the time that word is recognised by the brain.
	You may refer to the figure in your answer.
[6]
Quality of Written Communication [1]
[Total 7 marks]

11.	The cerebellum and medulla oblongata are regions of the brain. The cerebellum is concerned with the control and coordination of movement and posture.
	Suggest why the cerebellum of a chimpanzee is relatively larger than the cerebellum of a cow.
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[Total: 2 marks]

12.	In this question, one mark is available for the quality of the use and organisation of scientific terms.
	The medulla oblongata controls breathing, heart rate and blood pressure.
	Describe how the medulla oblongata responds to an increase in carbon dioxide concentration in the blood during exercise. Explain how this response leads to a decrease in the concentration of carbon dioxide in the blood.
[7]
Quality of Written Communication [1]
[Total 8 marks]

13.	The figure below shows a simplified diagram of a mammalian reflex arc.

(i)	Name S and T.
S ......................................................................................................................
T ......................................................................................................................
[2]
 
(ii)	Explain why the withdrawal of a hand, which has been subjected to pressure, is an example of a reflex action.
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[3]

(iii)	In this reflex, when pressure is applied to the receptor, impulses are generated in the sensory neurone.
	Outline what happens in the membrane of the sensory receptor in response to pressure.
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[3]
 
(iv)	Explain why, in the reflex arc shown in the figure above, impulses can only travel in the direction shown.
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[2]
[Total: 10 marks]

14.	In this question, one mark is available for the quality of spelling, punctuation and grammar.
	Mammals also rely on nerves to transfer information in the form of electrical impulses.
	Using the information shown in the figure below, outline how impulses are transmitted from receptor to effector.

[8]
Quality of Written Communication [1]
[Total 9 marks]

15.	Reflex actions are unlearned responses to a stimulus.
	Describe one advantage of reflex actions compared to learned responses in a mammal.
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[Total 1 mark]

16.	The figure below shows a vertical section through the human brain.

(i)	Name the structure shown above that links the two cerebral hemispheres.
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[1]

(ii)	The table below shows the functions of some areas of the brain.
	Complete the table using the labels in the figure above.
area of brain	example of function	
.......................................................	co-ordination of posture	
.......................................................	control of heart rate	
.......................................................	control of temperature regulation	
.......................................................	control of speech	
[4]
[Total 5 marks]

17.	Alzheimer’s disease is a complex, degenerative disease that affects the brain. The risk of developing this disease increases with age, particularly over the age of 65. Symptoms include a gradual loss of memory, disorientation, difficulty with learning, loss of language skills and a decline in the ability to perform routine tasks. The areas of the brain that control memory and thinking skills are affected first.
	State the functions of acetylcholine and acetylcholinesterase in synapses in the brain.
acetylcholine ............................................................................................................
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acetylcholinesterase ................................................................................................
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[Total 2 marks]

18.	The mammalian nervous system consists of the central and peripheral nervous systems.
	Describe how the central nervous system is protected from mechanical damage.
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[Total 3 marks]

19.	In this question, one mark is available for the quality of spelling, punctuation and grammar.
	The autonomic nervous system contains neurones that carry impulses to the internal organs.
	Describe the role of the autonomic nervous system in the control of the heart beat.
[7]
Quality of Written Communication [1]
[Total 8 marks]

20.	(a)	The cerebellum and medulla oblongata are both parts of the hindbrain. Outline the functions of these two parts of the brain.
cerebellum
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[2]
medulla oblongata
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[2]
 
(b)	Alzheimer’s disease is characterised by several changes in the cerebrum, including ‘tangles’ inside neurones and ‘plaques’ between neurones.
	State what causes
(i)	tangles; ..................................................................................................
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(ii)	plaques. .................................................................................................
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[2]

	Another change in the cerebrum of a person with Alzheimer’s disease is a decrease in acetylcholine released by neurones that form memory circuits.
	During a clinical trial, people with Alzheimer’s disease were treated with a drug that inhibited the enzyme acetylcholinesterase. This improved their short-term memory.
(c)	Suggest how the drug may inhibit acetylcholinesterase.
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[3]
 
(d)	Suggest how the drug improves short-term memory.
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[2]

(e)	State three precautions that should be taken when designing such clinical trials, to ensure that any effects are due to the drugs being tested.
1 ......................................................................................................................
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[3]
[Total 14 marks]

21.	Read the passage below and answer the questions that follow.
		Snake Venoms
	Some types of snake kill their prey and defend themselves by means of a poisonous bite.
	Fangs (hollow teeth) inject venom from specialised glands into the victim. The venom contains a protein, which is a toxin.
	Different species of snake have toxins that act in different ways. Haemolytic toxins are enzymes that hydrolyse phospholipids. They damage tissues, including heart muscle.
	Neurotoxins, such as the one produced by green mamba snakes, bind to acetylcholine receptors on the surface membranes of nerve cells or muscle fibres. This leads to muscle paralysis and heart failure.
 
	Some antibodies bind to toxins and inactivate them. These antibodies are known as antitoxins.
	The human immune response is far too slow to be effective in making antitoxins against snake venom.
	Injecting a very small, non-lethal quantity of venom into a horse produces antitoxin. The horse produces antitoxins that can be extracted from horse blood and used as an emergency treatment for those bitten by the same species of snake.
	Each time the horse is injected with venom, it is able to tolerate larger doses and the concentration of the specific antitoxin in its blood is greater.
 
(a)	State how enzymes which hydrolyse phospholipids damage tissues.
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[1]
 
(b)	Suggest how a neurotoxin which binds to acetylcholine receptors on muscle fibres would produce paralysis.
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[2]
 
(c)	Explain why the human immune response is too slow to protect a person from a snake bite.
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[2]
 
(d)	Explain why a horse is injected more than once with a small amount of venom when it is being prepared for use as a source of antitoxin.
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[3]

(e)	Why would treatment with horse antitoxin produce no long-term protection against snake bites?
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[2]
[Total 10 marks]

22.	The human brain is an organ, protected by the skull. The largest part of the human brain is the cerebrum. The surface of the cerebrum is covered by a highly folded region of tissue, called the cerebral cortex. The cerebrum contains regions of mostly myelinated axons, called white matter, and regions of mostly cell bodies and dendrites, called grey matter.
	Explain why the cerebral cortex is a tissue, whereas the brain is an organ.
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[Total 3 marks]

23.	The following is a list of the functions of the brain. Put a tick () in the box next to the function performed by the cerebrum.
control of the autonomic nervous system	
coordination of posture	
planning a task	
control of heart rate	
[Total 1 mark]

24.	(a)	During winter, the brown bear, Ursus arctus, enters a long period of inactivity. Whilst inactive, the brown bear undergoes various physiological changes, for example a decrease in core body temperature and a decrease in resting heart rate. There are also changes in the brown bear’s metabolism of protein and lipids.
	Explain the role of the autonomic nervous system in achieving a decrease in resting heart rate.
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[3]
 
	During periods of inactivity, the brown bear reabsorbs all urea molecules from the filtrate in its kidneys and from the bladder. Urea is then transported in the bloodstream to the large intestine. Bacteria in the large intestine convert urea to ammonia and carbon dioxide, which diffuse back into the blood. When the ammonia reaches the liver, it is converted into amino acids. These newly produced amino acids are then used to synthesise proteins in the body, especially in the liver and muscle cells.
(b)	Name two plasma proteins that will be produced by the liver.
1 ......................................................................................................................
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[2]
 
(c)	Describe the similarities and differences between the metabolism of nitrogen-containing compounds in inactive brown bears, as described in the passage, and in humans.
similarities
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differences
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[5]
 
	The blood plasma cholesterol concentration of inactive brown bears rises to twice the concentration found in normally active bears and in humans. However, brown bears do not suffer any of the cardiovascular diseases associated with high cholesterol concentrations in humans, as their liver produces a protective substance, which prevents these diseases from developing.
(d)	Explain the importance of cholesterol in the metabolism of mammals.
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[3]
 
(e)	Suggest how the protective substance produced by their liver prevents brown bears developing cardiovascular diseases.
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[2]
[Total 15 marks]