CXC CSEC Biology 2017 June P2

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FORM TP 2017045

TEST CODE

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CARIBBEAN EXAMINATIONS COUNCIL CARIBBEAN SECONDARY EDUCATION CERTIFICATE@ EXAMINATION

BIOLOGY Paper 02

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General Proficiency

2 hours 30 minutes

READ THE FOLLOWING INSTRUCTIONS CAREFULLY.

1.

This paper consists of SIX questions in TWO sections. AnswerALL questions.

2.

Write your answers in the spaces provided in this booklet.

3.

Do NOT write in the margins.

4.

Where appropriate, answers should be illustrated with diagrams.

5

If you need to rewrite any answer and there is not enough

6.

If you

space to do so on the original page, you must use the extra lined page(s) provided at the back of this booklet. Remember to draw a line through your original answer. use the extra page(s), you MUST write the question number clearly in the box provided at the top of the extra page(s) and, where relevant, include the question part beside the answer.

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO. Copyright @ 2015 Caribbean Examinations Council All rights reserved.

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-4SECTION A

AnswerALL questions in this section. ..

Write your answers in the spaces provided in this booklet.

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1.

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In an experiment, some students put corn seeds into each of two test tubes labelled A and B, as shown in Figure l.

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Apparatus and materials used for experiment

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Write a suitable aim for this experiment.

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In which of the tubes, A or B, would germination most likely occur? Give ONE reason for your answer.

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(2 marks)

(iii)

State TWO roles that the moisture from the coffon wool plays in the process

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The corn seedlings which germinated are placed in a pot and exposed to unidirectional light as shown in Figure 2.

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(i)

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What type of movement is shown by the plants in Figure 2?

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(1 mark)

(iD

State a hypothesis that the students could test by using the apparatus and materials shown in Figure 2.

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The students want the seedlings to grow straight towards the ceiling. Suggest how they could manipulate the apparatus to get this result.

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The seedlings shown in Figure 2 use all the nutrients stored in the cotyledons. Discuss the process by which these plants can make more nutrients.

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(v)

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Starch is the most coflrmon carbohydrate that is found in the leaves of green plants' Describe a test that the students could do in the laboratory to investigate whether starch is present in the leaves of the seedlings.

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(ii)

Name ONE plant organ, other than leaves, where starch may be found.

(1mark)

(iii)

Instead of starch, animals store complex carbohydrates such as glycogen. Name TWO organs in an animal's body which store glycogen.

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Total25 marks

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LIVING ORGANISMS Type of cells

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Number of cells

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Kingdom Monera Example: bacteria

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Unicellular

Kingdom Protista

Presence of cell wall

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Example

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(v) Tlpe of Nutrition

Kingdom

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Example: fish

Autotroph

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Kingdom Fungi

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Complete the classification by writing the correct answers at (i), (ii),

Figure (b)

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(iii), (iv)

and (v) in

(5 marks)

Each kingdom is further subdivided into taxa with the lowest rank being the level of

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species.

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Define the term 'species'.

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Using the human species as an example, explain why physical appearance or morphology isNOT always useful for identiffing organisms belonging to the same

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Suggest ONE reason why biologists use the biological concept of species instead of physical characteristics to classiff organisms.

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Some lizards were washed away on a log during a hurricane and landed on Several years later, they were classified as a new species.

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remote island.

Using the biological concept of a species, state TWO reasons why they were reclassified.

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(ii) ,.X-. ..f,t}.

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The new species of lizards living in the mountainous region of the island were found to be smaller than those living on the lowlands. Suggest TWO reasons for this variation.

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Figure 4 illustrates the events that take place during the human menstrual cycle.

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Hormone Y o

Hormone X

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Identifu Hormones X and Y and the event occuning at Z.

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Y ............... Z (3 marks)

(ii)

What is the role of EACH hormone in the menstrual cycle?

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Name the organ that produces Hormones X and Y.

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Discuss the fate of the following structures shown in Figure 4 the ovum occurs.

if fertillzation of

Corpus luteum

Uterus lining

(4 marks)

(b)

Some contraceptive pills contain hormones. Suggest how this may prevent pregnancy.

(1 mark) (c)

A drug company is developing a male contraceptive this could prevent pregnancy.

pill.

Suggest THREE ways in which

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in this booklet.

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(a)

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Explain how structures in the human eye control the amount of light that enters the eye.

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Jenny enters a dimly lit room and cannot see the colours of the furniture until the lights are switched on. Explain how Jenny is able to discern objects in the dimly lit room but cannot see the colours until the lights are switched on.

(5 marks)

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A certain form of colour-blindness is inherited as a recessive allele carried on the X chromosome. It is thus said to be 'X-linked'or'sex-linked'. Awoman with normal colour vision, whose father is colour-blind, mates with a colour-blind man. What is the chance of them having colour-blind children? Use a genetics diagram to explain your answer.

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Use B for the allele for normal vision and b for the allele for colour-blindness.

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Describe the chemical digestion of carbohydrates, fats and proteins from the mouth until they are absorbed in the small intestines.

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Describe how the body systems work together to assimilate glucose molecules

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(ii)

Explain how the assimilation of glucose by of a person suffering from diabetes.

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non-diabetic person differs from that

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Using a suitable example of EACH, distinguish between a predator-prey relationship and parasitism.

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Some environmentalists encourage the practice of introducing predators to an ecosystem to control a population of pests rather than the use of agricultural chemicals.

(i)

Outline THREE advantages and THREE disadvantages of this method ofbiological control compared to the use of chemicals.

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Explain how biological control may conhibute to biological evolution through natural selection in an ecosystem.

(3 marks)

Total 15 marks

END OF TEST IF yOU FINISH BEFORE TIME IS CALLED, CHECK YOUR WORK ON THIS TEST.

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