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Which term is defined as all the chemical reactions that occur in cells?
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The diagram shows a section of DNA from a chimpanzee.
Which diagram shows a section of DNA from the organism that is most closely related to the chimpanzee?
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The length of a mitochondrion in a photomicrograph is 15 mm.
The actual length of the mitochondrion is 3\mu m.
What is the magnification of the photomicrograph?
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The diagrams show a leaf and its internal structure.
What are the levels of organisation of the labelled structures?
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Different factors affect the rate of diffusion of molecules across a membrane.
Which row represents changes to factors that will increase the rate of diffusion?
[Table_1]
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A red blood cell and a palisade mesophyll cell are placed in a solution which has a higher water potential than the cells.
What will happen to each cell?
[Table_1]
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The diagram shows a protease molecule catalysing the break down of a protein molecule. What are the parts labelled P, Q, R and S? [Table_1]
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The diagram shows the structure of part of a DNA molecule. What does X represent?
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Which structure would be found in large numbers in cells that have a high energy requirement?
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What must be increased in the diet of a person suffering from constipation?
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Which disease can be caused by a deficiency of iron in the diet?
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The diagram shows the human alimentary canal, with a string marked in metres beside it.
How long is the small intestine?
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The graph shows the concentration of oxygen in the air spaces of a green leaf of a plant during a 12-hour period.
Which statement about carbon dioxide in the air spaces during time X is correct?
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What is a description of transpiration?
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The diagram shows the vessels associated with the flow of fluids to and from body cells.
Which is the lymph vessel?
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The diagram shows a cross-section through a human blood vessel.
Which type of blood vessel does the diagram show?
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Which are both chemical barriers to the transmission of pathogens?
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The table shows some of the changes that occur during breathing.
[Table_1]
Which changes occur to cause inspiration?
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In an experiment to investigate anaerobic respiration, two bottles are set up in a warm room, as shown.
What would happen to each balloon after one day?
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The graph shows the lactic acid concentration in blood during and after exercise. The continuation of which process accounts for the shape of the graph at Z?
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What is the most important function of sweating?
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Four effects of a specific hormone are listed.
• increased blood pressure
• increased blood glucose concentration
• increased rate of respiration
• reduced blood flow to the gut
What is this hormone?
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The diagram shows a person sweating in hot weather.
What part is played by sweat glands during the process of sweating?
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The diagram shows a synapse in a reflex arc.
What are the identities of the two neurones and in which direction does the neurotransmitter pass?
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The immune system recognises pathogens and attacks them.
Which feature of pathogens triggers this response?
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Which environmental factor is not always a requirement for seed germination?
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Which row shows the adaptive features of sperm cells?
[Table_1]
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In some mammals the allele for brown coat colour is dominant to the allele for white coat colour. Which percentage of offspring will be white if a cross is made between two heterozygous mammals?
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Which term is defined as a length of DNA that codes for a protein?
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The following are involved in protein synthesis.
1. amino acids assembled in order
2. mRNA moves to the cytoplasm
3. mRNA passing through a ribosome
4. DNA in the nucleus
In which order do they become involved when proteins are made?
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What makes tongue rolling an example of discontinuous variation?
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The distribution of the sickle-cell allele in human populations varies in different areas of the world. What is an explanation for this difference?
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Nitrogen in the air cannot be used by plants until it is in the form of nitrates. Which two processes convert nitrogen from the air into nitrates?
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What is shown by the widest block in a pyramid of numbers for a grassland ecosystem?
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The diagrams show the depth and rate of breathing in a person at 12.00 pm and 1.00 pm.
What happens to the person's breathing between 12.00 pm and 1.00 pm?
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Ligase enzymes are used in genetic engineering to
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What is not a reason for conservation programmes?
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Some examples of the waste products of human activity are discarded household rubbish, excess fertiliser, industrial chemicals and untreated sewage.
Which of these can both cause increased growth of aquatic plants?
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