Cambridge IGCSE Biology - 0610 - Supplement Paper 4 2015 Summer Zone 1

(a) Fig. 1.1 shows five species of mollusc.

Use the key to identify each species. Write the letter of each species (A to E) in the correct box beside the key.
Key
1 (a) body is completely or partly covered in a shell
(b) body is not completely covered or partly covered in a shell Limax flavus
2 (a) shell is attached to rocks by thin threads Mytilus edulis
(b) shell is not attached to rocks by thin threads go to 3
3 (a) shell is a spire that comes to a point Buccinum undatum
(b) shell is not a spire that comes to a point go to 4
4 (a) animal has tentacles Nautilus pompilius
(b) animal has 2 tentacles Planorbis planorbis
[3]
(b) State two features that are shown by all molluscs.
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2 .........................................................................
[2]

(a) Explain why the student included the following in the apparatus.
(i) The beaker of water and the thermometer.
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(a) (ii) The light meter and the ruler.
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(b) The results obtained by the student are shown in Fig. 2.2.
(i) Describe the student’s results.
You will gain credit if you use data from Fig. 2.2 in your answer.
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(b) (ii) State the factor that is limiting the rate of photosynthesis in region X of the graph.
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(b) (iii) Suggest and explain the reasons for the shape of the graph in region Y.
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(c) Counting bubbles may not be the best way to measure the rate of photosynthesis. The volume of the bubbles is not always exactly the same.
Suggest and explain one alternative way of measuring the gas given off to solve this problem.
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(d) Fig. 2.3 shows the carbon dioxide concentration in the atmosphere as determined at Mauna Loa in Hawaii between 1959 and 2013.
(i) Explain why the concentration of carbon dioxide has increased between 1959 and 2013.
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(d) (ii) Global warming is largely due to this increase in atmospheric carbon dioxide.
Explain how increases in atmospheric carbon dioxide concentrations contribute to global warming.
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(a) Put the stages into the correct sequence. Two have been done for you.
[Table_1]
H [ ] [ ] [ ] L [2]

(b) (i) Describe what happens at ovulation.
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(ii) Name the cell produced at fertilisation by the fusion of two gametes.
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(c) If an embryo implants in the uterus, the embryo secretes a hormone known as hCG that stimulates the reproductive organs of the woman to continue to secrete progesterone.

Describe what happens after fertilisation until the time that the embryo secretes hCG.
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(d) State two places where progesterone is produced during pregnancy.
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(e) (i) Fertility drugs are taken to increase the chance that a woman may become pregnant.

Describe and explain how these drugs improve the chances of becoming pregnant.
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(ii) Outline two social implications of using fertility drugs.
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A biologist made a slide of some epidermal cells from a scale leaf of an onion bulb.
Fig. 4.1 is a drawing that the biologist made of one of the cells.
[Image_1: Fig. 4.1]
(a) Table 4.1 shows the functions of the structures within a plant cell.
Complete the table by:
naming the part of the cell that carries out each function
using the letters from Fig. 4.1 to identify the part of the cell named.
[Table_1: Table 4.1]

(b) The biologist added a few drops of concentrated salt solution to the cells on the slide and took a photograph of the cells, as shown in Fig. 4.2.
[Image_2: Fig. 4.2]
(i) With reference to Fig. 4.2, describe the effect on the plant cells of adding a concentrated salt solution..................................................................................................................
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(ii) Use the term water potential to explain the effect you have described.
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Mammals have a double circulation system.
(a) Explain what is meant by a double circulation system.
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(b) Table 5.1 shows some of the main organs in a mammal and the vessels that deliver blood and take it away.
Complete the table.
Table 5.1
| organ | blood vessel |
|--------|--------------------------|
| | delivers blood | takes blood away |
| heart | 1 ........................... | 1 aorta
| | 2 ........................... vein | 2 ............................ artery
| lungs | pulmonary artery | ..............................
| liver | 1 hepatic artery | hepatic vein
| | 2 ........................... |
| kidney | ........................... artery | ............................ vein
[5]

(c) Table 5.2 shows the blood pressure in the different blood vessels that supply and drain a muscle in the leg.
Table 5.2
| blood vessel | mean blood pressure/kPa |
|-------------------------------|---------------------------|
| aorta | 13 |
| femoral artery | 12 |
| distributing/muscular artery | 9 |
| arteriole in muscle | 6 |
| capillary in muscle | 4-1.3 |
| venule in muscle | 1.1 |
| femoral vein | < 1.0 |
(i) The table shows that the mean blood pressure decreases from 13kPa in the aorta to 6kPa in the arterioles.
Explain why blood pressure must decrease in the arterioles before entering the capillaries.
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(ii) Explain how blood returns to the heart in the femoral vein against the pull of gravity.
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(d) Fig. 5.1 shows a section across part of an artery.

Fig. 5.1
With reference to Fig. 5.1, explain how the structure of an artery is related to its function.
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(a) (i) Draw a food chain for the organisms in the passages above. [2]
(ii) Complete Table 6.1 by stating the name and identifying the trophic level of each organism in the food chain.

Table 6.1
| name of organism | trophic level |
|---------------------|--------------------|
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| | | [3]
(iii) State two factors that influence the numbers of a top predator, such as wolves.
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2 ............................................................. [2]

(b) In the 1970s, the American ecologist Paul Colinvaux investigated the energy flow between moose and wolves.

His results are summarised in Table 6.2.

Table 6.2
| energy input or output or energy flow | energy / MJ |
|--------------------------------------|-------------------|
| consumed by moose | 4320000 |
| respiration of moose | 380000 |
| consumed by wolves | 56000 |
| respiration of wolves | 53000 |

(i) Calculate the percentage of the energy obtained by the moose that is consumed by the wolves. Show your working. ....................................... % [2]
(ii) Explain why the number of wolves on Isle Royale has never risen above 50 while the highest number of moose recorded is 2450.
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