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A person touches a hot object and rapidly moves their hand away from the hot object.
Which characteristic of living organisms is this an example of?
547
596
505
Which types of organisms are used in genetic modification because they have plasmids?
575
505
578
The list shows some of the structures contained in cells.
• cytoplasm
• cell membrane
• cell wall
• chloroplast
How many of these structures are found in the cells of all living organisms?
561
575
557
A student draws a red blood cell.
The diameter of the red blood cell they draw is 20 mm.
The actual diameter of the red blood cell is 0.008 mm.
What is the magnification of the student's drawing?
509
565
562
Samples of plant cells from the same species are immersed in three different liquids. The low concentration sucrose solution has a higher water potential than the plant cell cytoplasm. The high concentration sucrose solution has a lower water potential than the plant cell cytoplasm.
What is the state of the cells in the different liquids?
[Table_1]
531
538
541
Which process requires energy from respiration?
573
533
557
The diagram shows the sticky end of the DNA of a plasmid that has been cut by a restriction enzyme. The unpaired bases are labelled.
What is the correct sequence of the missing bases?
543
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581
A test was performed on a food substance. A positive result was shown by a colour change to blue-black.
What solution was used for the test?
518
541
583
A student investigates the breakdown of fats in milk by lipase. Four test-tubes labelled A, B, C and D are set up.
The table shows the contents of each test-tube.
In which test-tube will the contents become acidic most quickly?
[Table_1]
500
514
533
The diagram shows an experiment to investigate the effect of increasing light intensity on the rate of photosynthesis in an aquatic plant.
The rate is found by measuring the rate of bubble release by the plant.
As the light intensity increases, the rate of bubble release increases and then becomes constant.
Which statement describes why the rate of bubble release becomes constant at high light intensities?
599
518
577
The diagram shows a section through the leaf of a flowering plant.
Where does photosynthesis take place?
537
502
563
The diagram shows part of the alimentary canal and associated organs.
Which labelled part stores bile?
564
599
587
The list contains statements about villi.
1 Villi increase the efficiency of the absorption of nutrients.
2 Villi increase the efficiency of the alveoli during gas exchange.
3 Villi provide a large surface area.
4 Villi filter urea from the blood.
Which two statements explain the role of the villi in humans?
506
544
542
The diagrams show carbohydrate molecules as they pass through the alimentary canal.
Which row represents the molecules correctly?
[Table_1]
524
523
547
Which row shows correct information about three digestive enzymes in humans?
[Table_1]
564
504
509
Which substance found in a healthy diet helps to prevent constipation?
529
507
567
When is the transpiration rate of a well-watered plant highest?
513
597
534
Which statement is correct for a flowering plant during photosynthesis?
557
578
573
What is an advantage of having a double circulatory system?
505
594
589
The diagram shows the external structure of the human heart.
Which part is blocked in coronary heart disease?
561
574
572
One of the symptoms of the disease cholera is diarrhoea. This is due to water loss by osmosis caused by the cholera toxin.
What is the effect of cholera toxins that results in diarrhoea?
510
537
556
Which statement about immunity is correct?
570
558
588
What are the functions of the diaphragm and the cilia in the human gas exchange system?
[Table_1]
589
538
503
Vigorous exercise can cause an oxygen debt.
Which process removes the oxygen debt?
511
506
559
In healthy people, which substance is completely reabsorbed into the blood from the kidney nephrons?
582
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600
What would be the pupil size and lens shape of a person reading a mobile phone text message in a brightly lit room?
[Table_1]
500
560
555
What describes how the body maintains a constant internal temperature on a hot day?
595
569
502
What would lead to a decrease in blood glucose concentration?
534
544
545
Which statement about antibiotics is correct?
528
539
578
The diagram shows the carpel of a flower just after pollination.
What is the name of the part labelled X?
509
564
565
The table shows the percentage of sperm with different abnormalities in samples from a person with normal fertility and two people with low fertility.
[Table_1]
What are the causes of low fertility in person P and person Q?
579
585
595
Which word is used to describe stem cells?
501
567
512
The graph shows the concentration of four hormones during the menstrual cycle.
Which line represents progesterone?
550
567
544
The pedigree diagrams show the pattern of inheritance of a genetic disorder in four families.
This genetic disorder is not sex-linked.
Which pedigree diagram proves that the genetic disorder must be caused by a dominant allele?
553
529
557
What are correct statements about meiosis?
[Table_1]
551
525
569
The photograph shows a species of fish called a leafy sea-dragon.
Leafy sea-dragons live in areas of the sea where seaweed is present.
Which statements explain how natural selection caused the leafy sea-dragon species to develop?
1. Leafy sea-dragons that looked like seaweed were better adapted to their environment.
2. Leafy sea-dragons that survived passed on the allele for their appearance to their offspring.
3. Humans selected leafy sea-dragons that looked like seaweed.
593
571
595
What is the main source of energy input to biological systems?
511
591
564
Which organisms remove nitrate ions from soil?
545
545
531
What are two reasons for organisms becoming endangered?
1 habitat destruction
2 monitoring
3 education
4 pollution
5 captive breeding programmes
590
530
505
What is an example of the use of genetic modification in agriculture?
597
560
529
