Tuesday 21 May 2013

Question 1

C is a protein with a carbohydrate attached to it. This carbohydrate is formed by joining monosaccharides together.
Name the type of reaction that joins monosaccharides together. 1 mark

Answer 1

• Condensation

Question 2

Some cells lining the bronchi of the lungs secrete large amounts of mucus. Mucus contains protein.
Name one organelle that you would expect to find in large numbers in a mucus-secreting cell and describe its role in the production of mucus. 2 marks

Answer 2

• Mitochondria - the release of energy/ make ATP

- RER - makes polypeptides

Question 3

An enzyme catalyses only one reaction. Explain why. 2 marks

Answer 3

• Enzyme has active site

- Only substrates fits the active site

Question 4

Name the process by which oxygen passes from an alveolus in the lungs into the blood. 1 mark

Answer 4

• Simple diffusion

Question 5

Describe two adaptations of the structure of alveoli for efficient gas exchange. 2 marks

Answer 5

• Thin walls

- Total surface area is large

Question 6

People who have been fire-breathers for many years often find they cannot breathe out properly. Explain why. 2 marks

Answer 6

• Loss of elasticity
• Scar tissue
• Less recoil

Question 7

Infection by the cholera bacterium can cause acute diarrhoea. Explain how. 2 marks

Answer 7

• Toxin produced by the bacterium causes chloride ions to move into the lumen of the intestine.
• Water moves into the lumen by osmosis

Question 8

The scientists measured the rate of uptake of imatinib in μg per million cells per hour. Explain the advantage of using this unit of rate in this investigation. 2 marks

Answer 8

• Allow comparison

- Because different number of cells