Cambridge IGCSE Biology - 0610 - Supplement Paper 4 2012 Summer Zone 2

Fig. 1.1 A shows a cell from the lining of the alimentary canal.
Fig. 1.1 B shows a cell from the lining of a kidney tubule.
Both cells absorb substances into the blood.


(a) Name the structures labelled C on the cells in Fig. 1.1.
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(b) List three substances that are absorbed by both cells shown in Fig. 1.1.
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(c) Explain how both cells shown in Fig. 1.1 are adapted for absorption of substances into the blood.
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(d) Name the part of the alimentary canal that is lined by the cells shown in Fig. 1.1 A.
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(a) Define the term growth.
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(b) Name the response shown by the tomato seedling, F, which has bent 90° towards the light.
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(c) Using the results shown in Fig. 2.2, suggest what conclusions may be made about how the tomato seedlings detected the stimulus of unidirectional light.
You may refer to the seedlings by the letters E to H.
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(d) Explain the advantage of the response shown by seedlings to unidirectional light.
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(e) Responses to light are coordinated by plant growth substances known as auxins.
Explain the role of auxins in coordinating the response.
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(f) Research workers in India tested the hypothesis that pigments in tomato seedlings detect blue light. They used a variety of tomato seedling that does not have the ability to make a certain pigment.
These seedlings and a control group of seedlings were grown in the dark and then exposed to unidirectional blue light for 360 minutes.
The scientists measured the degree of bending of the seedling at intervals during the 360 minutes. Their results are shown in Fig. 2.3.

(i) Describe the results shown in Fig. 2.3.
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(ii) Suggest an explanation for the differences between the responses of the two groups of seedlings.
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(a) Explain the meaning of the term ecosystem.
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(b) State three ways in which mammals, such as the red slender loris, differ from other groups of vertebrates.
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(c) The large eyes of the red slender loris show that it is well adapted for a nocturnal way of life.
Suggest other features that the animal is likely to have that are adaptations to being active at night.
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(d) Discuss why areas of land, such as the Horton Plains National Park, must be conserved.
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(e) State how scientists could show that two populations of slender loris belong to the same species or to two different species.
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Fig. 4.1 shows a vertical section of a human heart. (a) Identify the blood vessels labelled J to M. J .............................................................. K .............................................................. L .............................................................. M .............................................................. [4] (b) Sensors that detect changes in blood pressure were placed into the blood vessels surrounding the heart. Recordings were taken at the times when the ventricles contracted and when they relaxed. The blood pressures recorded are shown in Table 4.1. [Table_1] Table 4.1 \[ \begin{array}{|c|c|c|} \hline \text{blood vessel} & \text{blood pressure / kPa} \\ & \text{contraction of the ventricles} & \text{relaxation of the ventricles} \\ \hline J & 16.0 & 10.0 \\ \hline K & 0.3 & 0.3 \\ \hline L & 0.3 & 0.3 \\ \hline M & 2.0 & 0.5 \\ \hline \end{array} \] (i) Explain why the pressure in blood vessel J is greater than the pressure in blood vessel M. .......................................................................................... .......................................................................................... .......................................................................................... .......................................................................................... [2] (ii) Explain why the pressure in blood vessels K and L is much less than the pressure in blood vessels J and M. .......................................................................................... .......................................................................................... .......................................................................................... [2] (c) Explain how the valves at N and O maintain one-way flow of blood through the heart. .......................................................................................... .......................................................................................... .......................................................................................... .......................................................................................... [4] (d) Other than in the heart, state where valves similar to those at O are found in the circulatory system. .......................................................................................... .......................................................................................... [1]

Fig. 5.1 shows the human male reproductive system and part of the urinary system.
(a) Complete Table 5.1 by identifying the structure in the male reproductive system shown in Fig. 5.1 that carries out each of the functions listed.
Write one letter only in each box. You may use the same letter more than once. There are some letters that you will not use. The first one has been done for you.

Table 5.1

| function | structure |
|----------------------------------|-----------|
| stores urine | A |
| produces gametes | |
| produces seminal fluid | |
| moves gametes by peristalsis | |
| produces testosterone | |
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(b) Describe how human male gametes differ from human female gametes.
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(c) Some women have difficulty becoming pregnant. They can be helped by taking fertility drugs. They can also be helped by artificial insemination.
(i) Describe how fertility drugs help women to become pregnant.
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(ii) Describe how artificial insemination is carried out.
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(a) Complete Table 6.1 by identifying the processes, P to U, in the nitrogen cycle shown in Fig. 6.1.

One process, S, has been completed for you.



Table 6.1

| stage | process |
|-------|-------------|
| P | |
| Q | |
| R | |
| S | deamination |
| T | |
| U | |

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(b) Use the results in Table 6.2 to describe the effect of radiation on the plants in both varieties.



Table 6.2

| feature | variety 1 | variety 2 |
|---------|----------------------|----------------------|
| | non-irradiated | irradiated | non-irradiated | irradiated |
| mean number of nodules per plant at 45 days | 12 | 21 | 7 | 21 |
| mean dry mass of nodules per plant at 45 days / g | 0.09 | 0.21 | 0.14 | 0.24 |

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(c) Suggest and explain what happens to the seeds when they are exposed to ionising radiation.

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(d) Researchers use plants that show useful features in selective breeding to improve varieties of the winged bean. The improvement of winged beans by selective breeding is an example of artificial selection.

Suggest how selective breeding is carried out with plants.

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(e) Scientists in Australia have put a gene from the bacterium Bacillus thuringiensis (Bt) into the cowpea, an important crop in Africa. This gene gives resistance against the cowpea pod borer, an insect pest that reduces the yield of cowpeas.

Explain how the method used by the Australian scientists differs from the technique used by the Ghanaian scientists.

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(f) Legumes, such as cowpeas and winged beans, are grown in between maize plants in a method known as intercropping.

Suggest the advantages to farmers of growing legumes and maize together in the same field at the same time.

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