Cambridge IGCSE Biology - 0610 - Supplement Paper 4 2017 Summer Zone 1

Fat is a necessary component of the human diet.
(a) State three ways in which the human body uses fat.
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The arrows in Fig. 1.1 show the pathway of fat in part of the alimentary canal.

(b) State the name of
(i) the enzyme secreted by the pancreas that digests fat
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(ii) the products of chemical digestion of fat
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(iii) the liquid that is produced by the liver and stored by organ P in Fig. 1.1
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(iv) organ P in Fig. 1.1.
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(c) Explain what happens to ingested fat at R in Fig. 1.1 before chemical digestion occurs.
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(d) Explain how the products of fat digestion are transported from Q to the rest of the body.
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One possible effect of too much fat in the diet is coronary heart disease.
(e) Describe how too much fat in the diet may cause coronary heart disease.
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(f) Describe and explain how coronary heart disease can be treated.
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The genes for antibodies are only active in lymphocytes.

(a) Define the term gene.

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(b) Lymphocytes produce antibodies.
Outline the role of antibodies in the defence of the body against pathogens.

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(c) Fig. 2.1 is a drawing made from an electron micrograph of a lymphocyte that produces antibodies.



Table 2.1 contains statements about the structures visible in Fig. 2.1.
Complete Table 2.1 by

• naming the structure
• identifying the letter that labels the structure

Heroin is a drug that acts on the nervous system.

(a) Define the term drug.
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There are pain receptors in the skin. These receptors transmit impulses along sensory neurones to the spinal cord.

Fig. 3.1 shows the synapses between sensory neurone A and a relay neurone and sensory neurone B and a relay neurone, in the spinal cord.

Fig. 3.2 is an enlarged view of the synapse between sensory neurone A and the relay neurone, as indicated by the circle on Fig. 3.1.

[Image_1: Fig. 3.1 and Fig. 3.2]

(b) Describe how impulses are transmitted across the synapse.
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(c) Suggest how the structure of a synapse ensures that impulses travel in one direction.
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(d) When an impulse arrives along sensory neurone B, a different neurotransmitter is released. This prevents the production of an impulse in the relay neurone.

Molecules of heroin have a similar shape to the neurotransmitter released from these neurones.

Explain how heroin affects the function of the synapse.
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(e) List three stimuli, other than pain, which humans can detect.
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Fig. 4.1 shows part of the circulatory system of a fish.
The arrows show the direction of blood flow.



(a) The circulatory system of fish is described as a single circulation.
State what is meant by a single circulation.
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(b) State the letter of the blood vessel in Fig. 4.1 that contains blood at the highest pressure.
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(c) The gills are the site of gas exchange.
State two features of gas exchange surfaces.
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(a) (i) State the genus of the giant quiver tree.

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(ii) Explain why the A. pillansii trees on Cornell’s Kop represent a population.
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(b) Suggest three reasons why the giant quiver tree is an endangered species.
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(c) It was estimated in 2005 that the total number of giant quiver trees in the wild was less than 3000, which is considered to be very low compared with other tree species.
Explain the risks to a plant species of having very small numbers.
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(d) The population of A. pillansii trees on Cornell’s Kop was surveyed and photographed at four sites, A to D, from 1937 onwards. Researchers took photographs at all four sites in 2004 and compared them with the original photographs.
The results are shown in Table 5.1. [Table_1]
(i) Calculate the percentage decrease in the number of living trees at site B from 1953 to 2004.
Show your working and give your answer to the nearest whole number.
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(ii) Describe what the analysis of the photographs shows about the population of A. pillansii on Cornell’s Kop.
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Students investigated the effect of mineral ion deficiencies on the growth of radish plants.
The seeds that were used in the experiment were from plants that had been self-pollinated for many generations and were therefore all genetically identical.
(a) Explain the advantage of using genetically identical radishes in this investigation.
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(b) State three other environmental factors that could affect the growth of the seedlings.
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The results of the investigation are shown in Table 6.1.
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(c) Describe and explain the results for the radishes grown without nitrate ions (group 2).
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(d) Describe the likely appearance of the radish plants grown in the solution without magnesium ions (group 3) and explain your answer.
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(e) Phosphate ions are a component of DNA.
Suggest why the radish plants in group 4 grew less than the radish plants in the complete solution (group 1).
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