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Which process provides an organism with the raw materials needed for tissue repair?
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525
Which name is given to a group of individuals that can reproduce to produce fertile offspring?
538
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572
The diagram shows a cross-section of part of a leaf.
Which type of cell carries out the most photosynthesis?
563
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513
Some examples of substances moving across membranes are listed.
1. glucose molecules into the epithelium that lines the small intestine
2. nitrate ions from a dilute solution in soil into a more concentrated solution in root hair cells
3. water molecules from mesophyll cells into the air spaces of a leaf
For which examples must oxygen be present?
548
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559
The graph shows how the turgor pressure inside a plant cell varies when the cell is placed in external solutions of different concentrations.
520
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592
The diagram shows a length of DNA.
What is the sequence of bases in the unlabelled strand of DNA, starting from the top of the diagram?
576
538
514
Amylase and pepsin are digestive enzymes. The shapes of their active sites are different. What causes the difference in the shapes of their active sites?
558
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593
The rate of an enzyme-controlled reaction decreases when the temperature falls below the optimum.
Some possible reasons why it slows down are listed.
1. The enzyme molecules are denatured.
2. The molecules have less kinetic energy.
3. The shapes of the substrate molecules are changed.
4. There are less frequent collisions between molecules.
Which reasons cause the reaction to slow down?
594
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507
Which description of an enzyme-catalysed reaction is correct?
523
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600
Four test-tubes are set up as shown. The test-tubes are kept at 20°C in a water-bath, in the light, for two hours. In which test-tube does the hydrogencarbonate indicator turn yellow?
501
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563
The substances listed are found in the leaf of a plant.
Which substance is obtained from the soil?
578
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578
The cholera bacterium produces toxins that cause chloride ions to be secreted into the small intestine.
What is the immediate effect of this on the water potential of blood in the intestinal capillaries, and on the water potential of the contents of the small intestine?
[Table_1]
592
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596
The graph shows the concentration of maltose in different parts of the alimentary canal.
What causes the change in concentration at X?
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550
The diagram shows a bean seedling soon after it has germinated. Where is most water absorbed?
563
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Scientists investigate the movement of substances in a plant.
They cut a ring of tissue from the stem.
Removing the tissue removes some of the transport vessels found around the edge of the stem.
A few days later they notice swelling above the area where the tissue has been removed.
What causes the swelling?
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The diagram shows the outside of a human heart. Which structure is a coronary artery?
550
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592
What happens in the heart when blood flows from the atria to the ventricles?
507
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517
Campylobacter is a bacterium that can cause food poisoning.
Which word describes Campylobacter?
543
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578
What is the approximate percentage of oxygen in expired air?
520
510
564
Which row shows processes that all use energy from respiration? [Table_1]
503
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524
What is the word equation for anaerobic respiration in yeast?
514
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568
Which substances are excreted from the human body?
1. carbon dioxide
2. urea
3. water
539
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575
What is a response to a low concentration of glucose in the blood?
507
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554
Which structure can reduce how much light enters the eye?
505
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577
The diagram shows a section through human skin. What are the structures labelled X, Y, and Z?
[Table_1]
590
502
583
A disease cannot be treated with antibiotics.
What could be the reasons for this?
1. It is not a bacterial disease.
2. The pathogen is a virus.
3. The patient has become resistant to the antibiotic.
586
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589
The diagram shows a strawberry plant. These plants can reproduce asexually by producing 'plantlets'.
Why is this method of reproduction useful to strawberry farmers?
585
574
592
Which statement about human gametes is correct?
520
527
551
The diagram shows the stages of protein synthesis in a cell.
Which row identifies molecules 1, 2 and 3?
578
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In some breeds of cattle, hair colour shows codominance. The coats may be red, white or roan (a mixture of red and white hairs).
What are the expected phenotypes when a parent with a red coat ($H^RH^R$) is crossed with a parent with a roan coat ($H^RH^W$)?
533
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543
A person who is homozygous for the sickle cell allele has a child with a person that is heterozygous.
What is the likelihood that the offspring would be homozygous for the sickle cell allele?
560
525
508
The diagram shows a food web.
How many organisms are feeding at more than one trophic level?
551
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527
The diagram shows part of the nitrogen cycle.
Which row shows the correct labels?
563
521
590
Which statement explains why bacteria are used in genetic engineering?
511
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507
The graph shows the growth of the fungus Penicillium and its production of the antibiotic penicillin in a fermenter.
Which stage of the Penicillium growth curve produces the highest concentration of penicillin?
522
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554
Which statement about sustainable resources is correct?
504
512
529
What is the least sustainable method of helping to maintain a population of fish in a lake?
506
576
514
