CSEC Biology Paper 2 January 2007 - Free CXC Past Paper with Answers

Using the information in Figure 2, draw TWO conclusions about the incidence of the disease.

Osteoporosis refers to a decrease in bone density, the bones become brittle, weakened and easily fractured.

Give TWO reasons that may account for the development of osteoporosis with age.

It has been suggested that osteoporosis is associated with oestrogen levels in women. State TWO functions of oestrogen.

If children were to be affected by osteoporosis, suggest TWO likely effects of the disease on their bodies.

Suggest a mineral supplement that is likely to be recommended for people suffering from osteoporosis.

Healthy bone is living tissue. Give TWO advantages of bone being a living tissue.

Apart from support, identify TWO functions of bone.

Figure 3 shows the menstrual cycle in a human female.

Figure 3. Menstrual cycle of the human female

Using the numbers I - IV, label Figure 3 to indicate where in the menstrual cycle EACH of the following events occur: a) Uterus wall builds up as oestrogen level rises (I) b) Many blood vessels develop (II) c) Shedding of the uterine wall (III) d) Uterine wall prepared for implantation (IV)

Identify TWO hormones involved in the menstrual cycle and give the function of ANY ONE.

State THREE functions of the placenta during development of the foetus.

State THREE birth control methods practised by human beings.

Suggest why birth control seems more important in humans than in other populations of mammals.

Using only the letters P, Q and R label the structures on both cells that perform EACH of the following: a) Produce ATP (P) b) Synthesise protein (Q) c) Allow substances to enter and leave the cell (R)

Using the letters S and T, label the structure on Cell 2 ONLY that performs EACH of the following functions: a) Converts light into chemical energy (S) b) Allows a wide range of substances to pass through (T)

Name structure X shown in Cell 1.

Structure X is absent from mature red blood cells and sieve tubes. Suggest one process which these cells will not be able to perform. Give a reason for your answer. Process: Reason:

What is likely to occur in Cells 1 and 2 of Figure 4 if they were placed in distilled water for over half-an-hour? Cell 1: Cell 2:

Explain why the changes in Cell 1 might be different from the changes in Cell 2 after half-an-hour in distilled water.

Although blood cells are in a watery medium (plasma) they do not absorb excessive amounts of water. Explain why this is so.

Persons living at very high altitudes where the air is rare (low oxygen concentration) have a larger number of red blood cells per unit volume of blood than those living at sea level.

Suggest why a person living at high altitudes requires a relatively large number of red blood cells.

Figure 5 is a labelled diagram of part of the breathing apparatus of fish.

Water passes over the gill rakers before passing over the filaments. Suggest the function of the gill rakers.

Identify ONE feature observed in Figure 5 that allows the filaments to function efficiently.

State ONE OTHER characteristic of the filaments that helps in their function.

Identify TWO structures in the breathing apparatus of humans that have similar functions to the parts of the gills illustrated in Figure 5

State THREE ways in which the lungs of a smoker may be affected by the smoking habit.

Smoking is one human activity that pollutes the environment. Identify TWO OTHER human activities that result in pollution.

Identify TWO effects of polluted waterways on aquatic life.