No questions found
(a) Define the terms sensitivity and involuntary action.
sensitivity ............................................................................................................................. .................................................................................................................................
involuntary action ....................................................................................................... .................................................................................................................................
(b) (i) Name parts A to D.
A .......................................................................................................................... B .......................................................................................................................... C .......................................................................................................................... D .......................................................................................................................... [4]
(ii) Nerve cells use active transport to move ions across their cell membranes.
Explain what is meant by the term active transport.
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(c) Explain what would happen to the reflex shown in Fig. 1.1 if the nerve was cut across at X-Y.
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(d) Fig. 1.2 shows the grasping reflex of a baby.
Suggest why it is a good idea to test a baby's reflexes immediately after birth.
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513
580
507
(a) Describe the two root systems shown in Fig. 2.1 and explain how each is an adaptation for survival in a desert ecosystem.
[4]
(b) Describe and explain two ways in which the leaves of desert plants reduce water loss in transpiration.
1.
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2.
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[4]
(c) Xylem and phloem are transport tissues in plants. They transport substances from organs that are known as sources to organs known as sinks.
Complete the table to show:
• two substances being transported in each tissue
• an organ that is a source for substances being transported in each tissue
• an organ that is a sink for substances being transported in each tissue.
[Table]
Tissue | Substances being transported | Source of substances in the plant | Sink for substances in the plant
--- | --- | --- | ---
Xylem | 1 ....................
2 .................... | |
Phloem | 1 ....................
2 .................... | |
[6]
528
506
509
(a) (i) The yield of potato tubers was greater in plot H than in plot E.
Calculate the difference in yield as a percentage of the yield in plot E.
Show your working.
Answer = ..................................................% [2]
(ii) Suggest and explain the importance of increased plant height in the production of tubers.
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(iii) Describe the effect of adding manure and chemical fertilisers on the yield of potato tubers.
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(iv) Manure and chemical fertilisers provide plants with nitrate ions.
Explain how extra nitrate ions in the soil may have increased the yield of the potatoes.
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(v) State why plot E was included in this investigation.
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(b) Discuss the advantages and disadvantages of adding chemical fertilisers to crops.
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576
580
520
(a) Explain what is meant by the term antibiotic.
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(b) Explain why
(i) only a few bacteria grew in dish B compared with dish A,
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(ii) more bacteria grew in C than in B.
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(c) Fig. 4.1 shows the effect of an antibiotic on a species of disease-causing bacterium.
Suggest why antibiotics should not be used too often.
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(d) Explain the possible effect of the X-rays on the bacteria.
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(e) State two ways in which the structure of a bacterium differs from the structure of a virus.
1. .......................................................................................................................................................................................
2. ............................................................................................................[2]
(f) Human Immunodeficiency Virus (HIV) infects cells of the immune system.
Describe the effects of HIV on the immune system.
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551
587
597
(a) (i) State how oxygen passes from the capillary into cell Q and describe the function of this gas in a cell.
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(ii) Name two substances required by cells, other than oxygen, that pass from the blood to the tissue fluid at R.
1. ...............................................................................................................................
2. ............................................................................................................................... [1]
(iii) Name two substances produced by cells that pass from the tissue fluid to the blood at S.
1. ...............................................................................................................................
2. ............................................................................................................................... [1]
(b) With reference to Fig. 5.1, describe and explain two ways in which capillaries are adapted to their function.
1. ...............................................................................................................................
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(c) Tissue fluid drains into vessel P at T and eventually returns to the blood.
(i) Name the type of vessel labelled P.
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(ii) Explain how fluid passes along these vessels.
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506
558
564
(a) Using information in Fig. 6.1, describe the trend in the concentrations of carbon dioxide and methane over the past 1000 years.
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(b) Suggest and explain reasons for the trend in the concentrations of carbon dioxide and methane that you described in (a).
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(c) Explain how gases, such as those shown in Fig. 6.1, contribute to the greenhouse effect.
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(d) People are encouraged to recycle materials, such as paper and plastics. Discuss the advantages of recycling materials, such as paper and plastics.
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586
500
506
