Cambridge IGCSE Biology - 0610 - Supplement Paper 4 2013 Summer Zone 2

The kidneys remove metabolic waste from the liquid part of the blood.
Name:
(i) the liquid part of the blood;
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(ii) the process that involves removing metabolic waste from the body.
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Fig. 1.1 shows a kidney tubule and its associated blood vessels.

(b) Describe the functions of the regions labelled A and B.
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Table 1.1 shows the concentrations of some substances in the blood at X, the fluid at Y and the urine at Z.
[Table_1]
(c) Name the substance shown in Table 1.1 that:
(i) has molecules that are too large to pass through the walls of capillaries;
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(ii) is all reabsorbed in the kidney;
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(iii) is a metabolic waste product.
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(d) Explain why the concentrations of sodium ions and urea are greater at Z than at Y.
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(e) People who have acute kidney failure are given dialysis treatment.
In dialysis machines, the blood flows through narrow tubes made from partially permeable membranes, surrounded by dialysis fluid.
(i) Dialysis fluid contains sodium ions.
Use the information in Table 1.1 to suggest the concentration of sodium ions that should be in the fluid and give a reason for your answer.
concentration ............................................................... g per 100 cm³
reason ......................................................................................................................................................
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(ii) State \textit{two} components of blood that are \textbf{not} in dialysis fluid.
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2 ..................................................................................................................[2]

(f) Heparin is added to the blood before it returns to the body from the dialysis machine. Heparin prevents a person’s blood from clotting.
Describe the process of blood clotting.
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Antibiotics are used to treat human diseases.
Many bacteria have become resistant to antibiotics. Some antibiotics can no longer be used
to treat certain diseases.
Samples of bacteria were taken from a person who had an infectious disease. They were
spread onto four Petri dishes of agar (agar plates). Three of these agar plates contained the
antibiotics 1, 2 or 3.
The results are shown in Fig. 2.1.

[Image_1: Fig. 2.1]

Fig. 2.1

(a) Explain why:

(i) no bacteria grew in the agar plate with antibiotic 2;
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(ii) bacteria grew in the agar plate with antibiotic 3;
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(iii) only a small number of bacteria grew with antibiotic 1.
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(b) Explain why it is important to carry out a test similar to that shown in Fig. 2.1 before
giving an antibiotic to a person infected with a bacterial disease.
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(c) Antibiotic resistance has become a major problem worldwide.
Suggest how the problem of antibiotic resistance can be limited.
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(d) Hormones are used to treat a variety of conditions.
The most common hormonal treatment is the use of insulin to treat diabetes. Most of
the insulin is produced using cells that are grown in large fermenters. These cells have
been genetically engineered to produce human insulin.
Fig. 2.2 shows the stages involved in transferring the gene for insulin from human cells
to bacterial cells.

[Table_1: Fig. 2.2]

(i) Put the stages into the correct sequence. Two have been done for you.
S Q [1]

(ii) Diabetes is often treated with human insulin that has been produced by genetically
modified cells. In most countries this type of insulin has replaced the insulin that
was prepared from animals.
Suggest the advantages of providing human insulin to people with diabetes rather
than insulin obtained from animals.
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Fig. 3.1 shows the front part of the eye.

The eye shown in Fig. 3.1 is far adapted, which means that the lens is focusing light from a distance.



The lens changes shape to alter the direction of light rays passing through the eye.

(a) Name:

(i) another part of the eye that also alters the direction of the light rays;
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(ii) the part of the eye where the light rays form an image.
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(b) An eye specialist measured the change in shape of the lens of a patient during an eye test. The specialist recorded the change in shape of the lens with the patient looking at a chart 10 metres away and when reading from a book. This is shown in Fig. 3.2.



(i) Write the letter D on Fig. 3.2 to show a time when the patient was looking at the chart that was 10 metres away. [1]

(ii) State how the ciliary muscles and suspensory ligaments act to change the shape of the lens during the time marked E on Fig. 3.2.

ciliary muscles
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suspensory ligaments
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(c) Outline how humans are able to see in colour.

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Sorghum bicolor is a cereal crop important in many dry areas of the world.
Fig. 4.1 shows some plants of S. bicolor growing in a field in China.

(a) S. bicolor is a monocotyledon.
State two features that are used to identify plants as monocotyledons.
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(b) Fig. 4.1 shows the flower heads of sorghum. Pollen is released from the individual flowers when they open.
Most sorghum flowers are self-pollinated and then self-fertilised.
(i) State the meanings of the terms pollination and fertilisation.
pollination
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fertilisation
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(ii) Describe two implications of self-pollination.
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(c) Describe the events that occur in flowering plants after fertilisation to form a seed.
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(d) In India, the cultivation of sorghum has decreased because now people prefer foods based on wheat and rice.
There are alternative uses of sorghum in the production of new foods, processed foods and as feed for animals.
Explain why it is less efficient to feed crops, such as sorghum, to animals rather than to use them for human foods.
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The alimentary canal is adapted for chemical and mechanical digestion.
(a) Explain how chemical digestion differs from mechanical digestion.
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(b) Table 5.1 shows four functions of the alimentary canal.
Complete the table by:
• naming the part of the system that carries out each of the functions;
• using the letters from Fig. 5.1 to identify the part of the system named.
One row has been completed for you.

Table 5.1

| function | name of part | letter from Fig. 5.1 |
|----------|--------------|----------------------|
| produces bile | liver | J |
| most soluble food is absorbed into the blood | | |
| indigestible food is egested | | |
| hydrochloric acid is produced | | |
| protease, lipase and amylase are produced | | |
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(c) Some people develop gallstones, made of cholesterol, that accumulate in the gall bladder and the bile duct. Gallstones block the flow of bile.
Explain how gallstones can affect the digestion of fat.
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(d) Cholesterol can also accumulate in the walls of the coronary arteries.
Explain the effects that this might have.
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In some countries forests are cleared by burning. This produces carbon dioxide and ash.

(a) Outline the environmental effects of an increase in carbon dioxide in the atmosphere as a result of burning forests.
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(b) The ash helps crops to grow because it is rich in minerals, such as magnesium ions, but it is deficient in nitrate ions.
Explain why nitrate ions and magnesium ions are important for plants.
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(c) When mineral ions from soils are washed into streams and rivers there is often a rapid growth of algae.
(i) State the name of the effect that is caused by adding mineral ions to streams and rivers.
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(ii) These streams and rivers often have low concentrations of dissolved oxygen. Explain why.
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(d) Untreated domestic sewage contains organic waste as well as dissolved minerals.
Outline how sewage is treated so that the water may be recycled as drinking water.
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