problem 1) Which of the following statements are true?
(a) are specialised (d) contain chloroplasts
(b) have a cell wall (e) have a cell membrane.
(c) have cytoplasm
problem 2) Match the following functions to cell structures listed below:
(a) controls cell division (c) controls entry of substances into a cell
(b) produces energy, (d) encloses a plant cell.
mitochondrion, cell membrane, nucleus, cell wall
problem 3) From the list below choose elements and compounds which you would expect to find in each of (a) proteins, (b) starch, (c) lipids.
nitrogen, glucose, carbon, amino acids, fatty acid, sulphur, oxygen, glycerol, hydrogen (A/R)
problem 4) A suspension of yeast is dropped into some hydrogen peroxide in the test-tube. The hydrogen peroxide fizzes vigorously and gives off oxygen.
(a) What further experiment must be carried out to test hypothesis that the enzyme in the yeast catalyses the breakdown of hydrogen peroxide?
(b) What result will (i) support the hypothesis, (ii) destroy the hypothesis?
(c) Describe your answers to (b).
problem 5) A student's account of an experiment reads as follows:
I placed some diastase powder (a starch-digesting enzyme) in some starch solution in a test-tube. By taking samples from the tube and testing them with iodine, I found that the starch gradually disappeared.
I repeated the experiment but added a few cubic centimetres of dilute sodium carbonate (an alkali) to the starch solution before adding the diastase. The starch took longer to disappear. I concluded that diastase had an optimum pH of 7 (neutral).
Criticise (a) the student's experimental design (as judged by the report), (b) the student' s interpretation of the results
problem 6) Which of the following statements best describes the process of respiration?
Respiration in living organisms is:
(a) the intake of oxygen and output of carbon dioxide
(b) the intake of food and the output of energy
(c) the intake of food and the release of carbon dioxide
(d) the breakdown of food to release energy
(e) the oxidation of food to carbon dioxide.
problem 7) Describe what an oxygen debt is and how it is caused.
problem 8) When carbohydrate is oxidised to carbon dioxide and water in the body, 21 kJ energy is produced for every litre of oxygen used. In an experiment, a girl absorbed 2 litres of oxygen in 10 minutes. What is her energy production in kilojoules per hour?