Variant 2 February/March 2016

1. The diagram shows a section of DNA, with four bases identified on one strand.

Which sequence of bases would be on the other strand, starting from the top?

2. Why is aspirin sometimes used as a drug to reduce the risk of coronary heart disease?

3. The diagram shows five stages in genetic engineering.

Which stages involve the formation of sticky ends?

4. The diagram shows the sex chromosomes of a woman and of a man. Their genotypes for a recessive sex-linked condition are also shown.

What are the chances that their daughter will show the sex-linked condition?

5. The diagram shows an experiment to investigate the response of a plant stem to gravity.

What is a suitable control for this experiment?

6. The diagram shows a large food molecule changing into smaller molecules.

What is process X?

7. Which row shows the chambers of the heart, from those with the thickest walls to those with the
thinnest walls?

8. The diagram illustrates changes in air pressure taking place inside the lungs during a complete cycle of breathing. Atmospheric pressure is 101 kPa.
At which point on the diagram are the ribs beginning to be lowered?

9. Which row shows the effects of deficiencies in nitrate and magnesium ions on plant growth?

10. The diagram shows a flower.
In which structure do seeds develop?

11. The data show the results of an investigation on osmosis using sticks of potato.

Which statements explain this change in length?

12. What are alleles?

13. The diagram shows the detailed structure of a plant cell.

What is organelle X?

14. What is not a feature of hydrophytes?

15. The lower end of a plant stem is placed in water coloured with red dye. After three hours, the stem is cut as shown in the diagram.
Which labelled region is stained red?

16. The table shows the conditions in four test-tubes containing equal amounts of starch and salivary amylase.
In which test-tube is the starch broken down fastest?

17. Possible effects of drug abuse include
1 addiction,
   2 reduced self-control,
   3 severe withdrawal symptoms.

Which effects may occur as a result of drinking too much alcohol?

18. By which process is water lost from a leaf?

19. What happens when a child is vaccinated against tuberculosis?

20. What is not an effect of the hormone adrenaline?

21. What is a correct way of naming an organism using the binomial system?

22. The careless use of nitrogenous fertiliser near rivers and lakes can cause eutrophication.
This results in the death of fish.
What is the direct cause of the death of the fish?

23. The diagram shows a palisade mesophyll cell from a green leaf.

In which labelled part does photosynthesis occur and where is starch stored?

24. The diagram shows a leaf.

Use the key to identify the plant to which the leaf belongs.

25. Which process is used to transport sucrose from the leaves of a plant to its flowers?

26. The graph shows pH changes in the mouth after eating.

Why is it a good idea to brush teeth after eating?

27. The diagram shows part of the alimentary canal and associated organs.

Which structures secrete enzymes that digest proteins?

28. What causes the diffusion of oxygen into a plant cell?

29. A plant with variegated leaves has the starch removed from its leaves by placing it in a dark cupboard for 48 hours.
Black paper is then fixed on one leaf as shown and the plant is exposed to light.
After 24 hours, which part of the leaf contains starch?

30. The diagram shows a pyramid of numbers in a food chain.

What type of organism is the hawk?

31. In sexual reproduction in humans, why are sperm cells produced in much greater numbers than
egg cells?

32. What is not an example of active transport?

33. The diagram shows organisms feeding on a dead rat and one of the organisms which, in turn, feeds on them.

What is needed to complete the food chain?

34. The diagram shows the structure of a kidney tubule.
Where does filtration occur?

35. A person eats a large bowl of rice.
What happens to the amounts of insulin, glucagon and glycogen in their body?

36. The fovea of the eye has three kinds of cones absorbing light of different colours.
Which row is correct?

37. What helps oxygen to be absorbed rapidly into the blood in the lungs?

38. Which hormone maintains the lining of the uterus during pregnancy?

39. The diagram shows the inheritance of ABO blood groups. The blood groups of some of the individuals are given.

What could be Priya’s genotype?

40. The diagram represents the shape of an enzyme molecule.

With which substrate would this enzyme most easily form an enzyme-substrate complex?