1.	Excretion and secretion are two processes that take place in the body of a mammal.
	Complete the table below to compare the processes of excretion and secretion.

	excretion	secretion	
one difference			
one example of a product			
one similarity			
[Total 3 marks]

2.	Over 2.3 million people in the UK are known to have diabetes. It is also estimated that a further 0.5 million people have the condition but are unaware of it.
(i)	Explain how Type 1 diabetes is caused.
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[2]

(ii)	Describe three factors that increase a person’s risk of developing Type 2 diabetes.
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[3]
[Total 5 marks]

3.	The pancreas contains endocrine tissue. The figure below shows an electronmicrograph of a section of pancreatic endocrine tissue.

(a)	Name the endocrine tissue shown in the figure.
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[1]
 
(b)	Name the hormone present in the secretory vesicles of alpha cells.
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[1]

(c)	During vigorous exercise, the blood glucose concentration falls.
	Describe the changes that take place to make sure that the blood glucose concentration does not fall to a dangerous level.
	In your answer, you should use appropriate technical terms, spelled correctly.
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[6]
[Total 8 marks]

4.	In an experimental gene therapy for insulin-dependent diabetes, the insulin gene was combined with a glucose-sensitive promoter and inserted into liver cells of diabetic rats. The mean concentration of insulin was then measured at three different concentrations of blood glucose. The results are shown below.
concentration of
blood glucose / mg dm–3	mean concentration of
insulin / ng cm–3	
100	0.3	
300	5.0	
500	7.0	
	With reference to the table above, explain the role of the glucose-sensitive promoter in this gene therapy.
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[Total: 3 marks]

5.	An investigation was carried out into the effect of consuming meals rich in carbohydrate on two hormones in the blood.
	The figure below shows the relationship between glucose concentration in the blood and the concentrations in the blood of the two hormones, Q and R.

	Name hormones Q and R.
Q ..................................................................
R ..................................................................
[Total 2 marks]

6.	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]

7.	In both plants and animals, chemical messengers help to transfer information from one part of the organism to another to achieve coordination.
	The table below lists some of these chemicals together with their functions.
	Complete the table.
name of chemical messenger	function	
................................................................	controls water permeability of collecting
ducts in kidney	
insulin	................................................................
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glucagon	................................................................
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................................................................	stimulates stomatal closure during water
stress	
................................................................	controls apical dominance	
[Total 5 marks]

8.	Following a meal rich in carbohydrates, the plasma glucose concentration rises.
	Describe the homeostatic mechanisms that would normally prevent glucose appearing in the urine.
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[Total 5 marks]

9.	The pancreas is a gland that has both endocrine and exocrine functions.
	The figure below shows a section through part of the pancreas.

magnification × 400
 
(i)	Name A and B.
A ......................................................................................................................
B ......................................................................................................................
[2]

(ii)	Explain the difference between the terms endocrine and exocrine with regard to the pancreas.
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[4]
[Total 6 marks]

10.	The liver plays an important role in carbohydrate metabolism. The balance between the processes of glycogenesis and glycogenolysis helps to regulate the concentration of glucose in blood plasma. The figure below shows some of the stages of these processes.

(a)	(i)	Name one other hormone that promotes glycogenolysis.
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[1]

(ii)	Explain why glycogen is suitable for energy storage in cells.
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[3]
 
	The last step in glycogenesis is catalysed by the enzyme glycogen synthetase. The first step in glycogenolysis is catalysed by the enzyme glycogen phosphorylase.
	Glucose molecules have direct effects on glycogen synthetase and on glycogen phosphorylase. These effects do not require the presence of insulin and glucagon.
	The table below shows the rate of activity of glycogen synthetase and glycogen phosphorylase inside liver cells, during exposure of the cells to a concentrated solution of glucose.
time after addition of
glucose solution / s	rate of activity of
glycogen synthetase /
arbitrary units	rate of activity of
glycogen phosphorylase /
arbitrary units	
0
30
60
90
120
150
180
210	28
28
32
49
94
136
189
272	410
280
140
65
42
40
40
40	

(b)	Explain how a high concentration of glucose causes the storage of glycogen in liver cells. You will gain credit if you use the data in the table in your answer.
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[5]
 
(c)	After a prolonged period of fasting, glycogen levels in the liver are depleted. However, the liver can still produce glucose by the process of gluconeogenesis.
	Describe one way in which this is done.
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[3]
[Total 12 marks]

11.	Explain the term endocrine gland.
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[Total 2 marks]

12.	Untreated diabetes is a condition that can lead to blood glucose concentrations often rising above 120 mg 100 cm–3 of blood. Genetic engineering has been used to improve the treatment of diabetes.
	Explain the advantages of using genetic engineering in the treatment of diabetics.
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[Total 3 marks]

13.	Sections of young, growing stems were cut from just below the terminal buds of several similar plants of the same species. Each section was 5 mm long.
	The stem sections were placed in Petri dishes containing different solutions of auxin, with ten sections in each dish.
	After 12 hours, the sections were removed from the Petri dishes and measured.
	The figure below shows the mean increase in length of the sections in each dish, plotted against the concentration of auxin in the solution in the dish.

(a)	(i)	Using the figure above, describe the relationship between the concentration of auxin in the solutions in the Petri dishes and the mean increase in length of the stem sections.
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[3]

(ii)	List three variables which should have been controlled in the investigation.
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[3]
 
(b)	Suggest two ways in which auxin might have caused the change in growth of the stems as shown in the figure above.
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[2]
 
(c)	State two ways in which the control of plant growth by growth substances differs from the control of blood sugar concentration by mammalian hormones.
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[2]
[Total 10 marks]