CSEC Biology Paper 2 May/June 2013 - Free CXC Past Paper with Answers

Figure 2 is a diagram of the human eye.

On Figure 2, write the name of the part and use a label line to identify EACH of the following parts of the eye (i) The light sensitive layer (ii) The jelly-like substance that keeps the eye in shape (iii) Carries nerve impulses to the brain (iv) Controls the shape of the lens

Statements A and B below describe two different examples of plant movement. A. The roots of seedlings grow downwards in the soil. B. The shoots of cucumber seedlings grow towards light coming through an open window.

(i) Name the stimulus for EACH set of seedlings. Seedlings in A Seedlings in

(ii) Name the hormone responsible for the response of the cucumber seedlings in

(iii) Suggest how the types of movement described in A and B may be useful to the seedlings. A B

Certain soil invertebrates show a marked response to moisture. Describe ONE similarity and ONE difference between the response of soil invertebrates and the response of the cucumber seedlings in B. Similarity Difference

Outline TWO ways in which the nervous system functions differently from the endocrine system in humans.

Name metabolic waste products excreted by plants.

Figure 3 shows a side view of the human male reproductive system.

Figure 3. The human male reproductive system

Name the parts labelled A, and C in Figure 3.

The kidneys excrete urea and water in the form of urine. Use arrows on the diagram in Figure 3 to show the pathway taken by urine on its way out of the male's body.

Contraceptive methods may be temporary or permanent. Explain how ONE structure in Figure 3 can be manipulated to achieve permanent sterility in males.

Explain how tubal ligation results in sterility in females.

New shoots can grow from the buds or 'eyes' of a potato tuber. Explain ways in which this method of reproduction is different from reproduction in humans.

The human body comes into contact with many pathogens. Some of these pathogens are spread by vectors. Name ways by which the human body prevents itself from becoming infected.

Describe the life cycle of a named insect vector.

Explain how knowledge of the life cycle of this insect vector can be used to prevent the transmission of a named pathogenic disease.

A student is about to travel to a country where yellow fever is rampant. Explain how a vaccine can provide the student with active acquired immunity against this disease.

Discuss why a vaccine that provides passive acquired immunity is NOT suitable for this student.

Define EACH of the following terms with reference to the mangrove swamp ecosystem:

• Population
• Physical (abiotic) factors
• Habitat

Some investors want to remove the mangrove swamp in an area near your home, to develop the land for housing. Propose ONE argument to support this plan and TWO arguments against it.

Explain the effect on the carbon cycle of cutting and burning large areas of mangrove trees across the Caribbean.

Space for diagram Write your answer to Question 6 here.

Sketch an outline of the human body and show the location of the pancreas and the pituitary gland in the outline.

Name ONE hormone secreted from EACH of the endocrine glands in (a) (i) above.

The pancreas also produces en ymes that are important in digestion. Name T O factors that may affect the activity of these en ymes.

Explain how hormones secreted from the pancreas work together with the liver to regulate blood sugar levels.

If you were lost on a desert island for two days, how would a hormone secreted from your pituitary gland work to prevent you from becoming completely dehydrated?