CSEC Biology Paper 2 May/June 2011 - Free CXC Past Paper with Answers

Suggest ONE reason why humans need oxygen to stay alive.

Write a chemical equation which summarises the process for which oxygen is required in living cells.

Name the process at (a) (ii) above.

In which cell organelle does the process at (a) (iii) take place?

During his spectacular sprint, Usain Bolt's muscle cells became starved of oxygen. Explain why this happens in exercising muscles.

What substance is produced in Bolt's muscles which were starved of oxygen?

Explain how the substance in (b) (ii) above could affect Bolt's performance if he continued running for another 10 minutes.

Some plant species are able to survive in conditions where oxygen is lacking. Name the process by which these plants get their energy.

Describe the process named in (c) (i) above and state TWO substances produced by this process.

Explain the unique role of producers in the ecosystem.

Identify A and B.

A B

Using a named example, explain the role of B in the ecosystem.

Example Role

Give ONE example of a decomposer and explain how a decomposer releases carbon dioxide to the atmosphere.

Example Carbon dioxide

Suggest why energy from the sun flows in one direction while materials are cycled within the ecosystem.

In addition to energy, materials are also cycled through various trophic levels and the abiotic environment. Using a diagram of the nitrogen cycle, show FOUR named processes which assist in recycling nitrogen in the ecosystem.

State the name of the organism responsible for ONE of the processes named in (c) above.

Describe TWO ways in which a leaf is adapted for the process of photosynthesis.

Some students carried out an investigation to find out whether chlorophyll is needed for photosynthesis. They took a de-starched potted plant with a variegated (green and white) leaf and left it in sunlight for a few hours. A student then removed one leaf from the plant and tested it for starch. The student drew the leaf before the starch test. (i) Make a large, clearly labelled drawing to show the distribution of green and non-green areas of one leaf that the student may have used. (ii) Indicate, on the same drawing, the part expected to change colour if the leaf had photosynthesised. (iii) Describe the colour change expected if the leaf tested positive for starch.

Explain how this investigation could indicate that chlorophyll is needed for photosynthesis. Include the role of chlorophyll in your explanation.

Give an explanation for the presence of starch in the parts of a plant that do NOT contain chlorophyll.

Name TWO substances excreted by the kidney.

With the aid of an annotated diagram, explain how urine is formed in the human kidney.

An analysis of a sample of urine shows the presence of blood cells and glucose. Account for the presence of these substances in the urine.

Complete the following table by giving ONE example of EACH of the following categories of disease <br>

Plants can be genetically engineered to make them resistant to diseases. <br> (i) State what is meant by 'genetic engineering'. (ii) Discuss the possible social, ethical and ecological implications of genetic engineering.