CSEC Biology Paper 2 May/June 2014 - Free CXC Past Paper with Answers

Figure 4 shows an external view of the human heart.

Figure 4. External view of the human heart

Identify the structures labelled A, B and C in Figure 4. Write your answers on the lines provided in Figure 4.

Explain how the function of the heart may be affected by a blockage of the blood vessel shown at X.

Figure 5 shows blood vessels used to transport fluids around the body of a mammal.

Figure 5. Blood vessels in a mammal

Which blood vessel, A or B, represents a vein?

Identify ONE structure visible in Figure 5 which helps a vein to carry out its function.

Explain how the structure identified in (b) (ii) allows the vein to fulfil its function.

Diets high in saturated fats may lead to the formation of plaques in blood vessels. Explain how such deposits may lead to hypertension.

Figure 6 shows the transport vessels of a flowering plant.

Identify the vessels shown at Positions P and Q in Figure 6. 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Explain why plants do NOT need an organ like a heart in their transport system, and outline ONE mechanism by which plants move fluids through their transport vessels.

Figure 7 is a diagram of a nephron found in a human kidney.

Identify the structures labelled A, B and C in Figure 7 and briefly describe the process that takes place in EACH of these structures.

Name the hormone secreted by the pituitary gland when there is NOT enough water in body cells.

Explain why the composition of urine produced at X would differ in someone who drank a lot of water compared to someone who had no water to drink for over 24 hours.

Table 2 shows a comparison of the substances found in the urine of a healthy person and that of someone who is diabetic.

TABLE 2: COMPOSITION OF URINE OF A HEALTHY PERSON AND OF A DIABETIC PERSON

Explain why there is glucose in the urine of the diabetic person, assuming that the kidneys are functioning properly.

Describe TWO ways of managing diabetes mellitus.

With the aid of a diagram, outline THREE processes which return carbon to the atmosphere and ONE which removes it. (Include the form in which the carbon is found in the atmosphere.) Space for diagram (a)

Describe the impact of cutting down or burning large areas of forest on the recycling of carbon.

Suggest THREE ways in which humans can make changes in their day-to-day activities to reduce the amount of carbon in the atmosphere.

Define the terms 'genotype', 'phenotype', 'recessive' and 'dominant'.

Albinism (lack of pigmentation) is an example of discontinuous variation. Give TWO examples of traits that show continuous variation.

A man with normal pigmentation and an albino woman produce two children, one of whom is an albino. Using appropriate symbols, draw a genetics diagram to show the genotypes of the parents and the expected phenotypes of the offspring. (Note that albinism is a trait caused by the inheritance of a recessive allele.)

Many of the antibiotics used to control tuberculosis are no longer effective. Use the theory of natural selection to account for this.

Name THREE types of tissue which coordinate to bring about movement in animals, and state THREE reasons why it is important for animals to be able to move.

Explain why, unlike animals, plants are able to survive without moving from place to place.

A father saw his son step down onto the tarmac and watched as he ran towards him. Describe the changes that occurred in the father's eyes to keep his son's face in focus.