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1

The diagram shows a stage micrometer on which the small divisions are 0.1 mm. It is viewed through an eyepiece containing a graticule. The stage micrometer is replaced by a slide of a plant cell. What is the width of a chloroplast?

1. Cell structure  →  1.1. The microscope in cell studies

13. Photosynthesis  →  13.1. Photosynthesis as an energy transfer process

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2

The diagram shows an electron micrograph of a typical animal cell. X What is the function of the membrane system labelled X?

13. Photosynthesis  →  13.1. Photosynthesis as an energy transfer process

12. Energy and respiration  →  12.2. Respiration

1. Cell structure  →  1.2. Cells as the basic units of living organisms

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3

The diagram shows an electron micrograph of a plant cell. X Y Z What do structures X, Y and Z contain?

1. Cell structure  →  1.2. Cells as the basic units of living organisms

13. Photosynthesis  →  13.1. Photosynthesis as an energy transfer process

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4

Which organelles are found in the cells of both eukaryotes and prokaryotes?

1. Cell structure  →  1.2. Cells as the basic units of living organisms

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5

The diagram shows a high-power drawing of a plant cell. The actual length of the cell between X and Y was 160 µm. X Y What is the magnification of the cell?

1. Cell structure  →  1.1. The microscope in cell studies

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6

Which statement is true for cellulose, but not true for protein?

12. Energy and respiration  →  12.1. Energy

2. Biological molecules  →  2.3. Proteins

2. Biological molecules  →  2.2. Carbohydrates and lipids

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7

Heating with which solution breaks glycosidic bonds?

2. Biological molecules  →  2.1. Testing for biological molecules

2. Biological molecules  →  2.2. Carbohydrates and lipids

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8

Which level of protein structure maintains the globular shapes of enzymes?

2. Biological molecules  →  2.3. Proteins

3. Enzymes  →  3.1. Mode of action of enzymes

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9

Which type of bond is involved in maintaining primary, secondary and tertiary structure in protein molecules?

2. Biological molecules  →  2.3. Proteins

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10

What is the function of iron in the haemoglobin molecule?

2. Biological molecules  →  2.3. Proteins

8. Transport in mammals  →  8.2. Transport of oxygen and carbon dioxide

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11

As a frozen lake warms after a cold winter, mineral nutrients are brought to the surface. Which properties of water contribute to this process?

2. Biological molecules  →  2.4. Water

8. Transport in mammals  →  8.1. The circulatory system

7. Transport in plants  →  7.2. Transport mechanisms

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12

The graph shows the activation energy of an enzyme-catalysed reaction and the same reaction without a catalyst. Which arrow shows the activation energy of the uncatalysed reaction?

12. Energy and respiration  →  12.2. Respiration

3. Enzymes  →  3.1. Mode of action of enzymes

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13

How does increasing substrate concentration affect the rate of an enzyme-catalysed reaction in the presence of a competitive inhibitor?

3. Enzymes  →  3.2. Factors that affect enzyme action

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14

The diagram shows part of a cell surface membrane. P Q R What is the correct function for each of the structures labelled?

4. Cell membranes and transport  →  4.1. Fluid mosaic membranes

12. Energy and respiration  →  12.2. Respiration

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15

Strips of potato tuber tissue were immersed in distilled water or in sucrose solutions of different concentrations. The graph shows the percentage change in length of the strips. time / hours change in length of strips / % _10 _20 distilled water 0.1 mol dm _3 0.4 mol dm _3 Which statement explains the change that occurred in the potato strips immersed in 0.1 mol dm–3 sucrose solution?

4. Cell membranes and transport  →  4.2. Movement into and out of cells

7. Transport in plants  →  7.2. Transport mechanisms

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16

Which process would allow the movement of large protein molecules out of the cell?

4. Cell membranes and transport  →  4.2. Movement into and out of cells

7. Transport in plants  →  7.2. Transport mechanisms

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17

To which of the processes shown...

5. The mitotic cell cycle  →  5.1. Replication and division of nuclei and cells

5. The mitotic cell cycle  →  5.2. Chromosome behaviour in mitosis

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18

The diagram shows the chromosomes of a cell at late prophase of mitosis. What will be the appearance of the products of this cell division as they enter prophase of their next division?

5. The mitotic cell cycle  →  5.2. Chromosome behaviour in mitosis

5. The mitotic cell cycle  →  5.1. Replication and division of nuclei and cells

16. Inheritance  →  16.1. Passage of information from parents to offspring

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19

A diploid nucleus in a species of fruit fly has 8 chromosomes. How many DNA molecules are present in the nucleus at the end of interphase?

16. Inheritance  →  16.1. Passage of information from parents to offspring

5. The mitotic cell cycle  →  5.1. Replication and division of nuclei and cells

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20

What is the function of the enzyme DNA polymerase in a cell?

6. Nucleic acids and protein synthesis  →  6.2. Protein synthesis

6. Nucleic acids and protein synthesis  →  6.1. Structure of nucleic acids and replication of DNA

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21

A culture of bacteria had all its DNA labelled with the heavy isotope of nitrogen, 15N. The culture was then allowed to reproduce using nucleotides containing normal 14N. The DNA was examined using a centrifuge after one generation and again after two generations. The diagram shows the position of the DNA band at Z in the centrifuge tube when the DNA was first labelled. X Y Z In which pattern would the DNA be found after the first and after the second cell generations?

6. Nucleic acids and protein synthesis  →  6.1. Structure of nucleic acids and replication of DNA

19. Genetic technology  →  19.1. Principles of genetic technology

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22

What terminates the formation of a polypeptide chain during protein synthesis in cells?

6. Nucleic acids and protein synthesis  →  6.2. Protein synthesis

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23

Mammalian skin cells in tissue culture were supplied with a source of radioactive thymine. At which stage in the cell cycle will the thymine be used in the nuclei?

5. The mitotic cell cycle  →  5.1. Replication and division of nuclei and cells

16. Inheritance  →  16.1. Passage of information from parents to offspring

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24

Which organelles occur in large numbers in companion cells in phloem?

1. Cell structure  →  1.2. Cells as the basic units of living organisms

7. Transport in plants  →  7.2. Transport mechanisms

7. Transport in plants  →  7.1. Structure of transport tissues

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25

A water potential gradient causes water to move through xylem. Which process is mainly responsible for this water potential gradient?

4. Cell membranes and transport  →  4.2. Movement into and out of cells

7. Transport in plants  →  7.2. Transport mechanisms

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26

During transpiration, what is the site of evaporation of water in the leaves?

7. Transport in plants  →  7.2. Transport mechanisms

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27

The table summarises some characteristics of arteries, veins and capillaries. characteristics arteries veins capillaries blood pressure high low low lumen wide narrow narrow wall thick thin single cell Which lines in the table are correct?

8. Transport in mammals  →  8.1. The circulatory system

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28

The graph shows the oxygen dissociation curves of the pigments myoglobin and haemoglobin. saturation of pigment / % partial pressure of oxygen / kPa myoglobin haemoglobin Using information contained in the graph, what is the comparison between haemoglobin and myoglobin at a partial pressure of oxygen of 2 kPa?

8. Transport in mammals  →  8.2. Transport of oxygen and carbon dioxide

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29

When climbing a very high mountain there is a risk of altitude sickness. What causes altitude sickness?

8. Transport in mammals  →  8.2. Transport of oxygen and carbon dioxide

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30

The diagram shows a magnified section through the lung tissue. What are 1, 2, 3 and 4?

9. Gas exchange  →  9.1. The gas exchange system

8. Transport in mammals  →  8.1. The circulatory system

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31

The first diagram shows a spirometer, which is an apparatus used to measure changes in lung volume. The cover rises during exhalation and falls during inhalation, producing a trace on the rotating drum. The second diagram shows a typical trace from a spirometer. lung volume time X Y Z mouthpiece one way valves carbon dioxide absorber breathing tubes water seal medical grade oxygen rotating drum cover which rises as subject breathes out and falls as subject breathes in Which would give the vital capacity?

8. Transport in mammals  →  8.2. Transport of oxygen and carbon dioxide

9. Gas exchange  →  9.1. The gas exchange system

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32

Some studies suggest that smoking increases the risk of developing lung cancer. The two graphs show the percentage of smokers and the deaths from lung cancer in men of two age groups between 1950 and 1998. smokers / % of age group deaths per 100 000 of age group 1950 1960 1970 1980 1990 2000 aged 35 – 59 aged 60 – 74 key year year Which statement is not supported by the data in the graphs?

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33

The table shows four infectious diseases and the pathogen responsible. Which row in the table is correct?

10. Infectious diseases  →  10.1. Infectious diseases

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34

For which diseases is treatment with antibiotics likely to be effective?

10. Infectious diseases  →  10.1. Infectious diseases

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35

What is the difference between B and T lymphocytes in the immune system?

11. Immunity  →  11.1. The immune system

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36

Cells which divide and give rise to lymphocytes are called stem cells. Where in the human body do these stem cells divide?

5. The mitotic cell cycle  →  5.1. Replication and division of nuclei and cells

11. Immunity  →  11.1. The immune system

8. Transport in mammals  →  8.1. The circulatory system

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37

The numbers on the diagram refer to different types of immunity. by antibodies passing through placenta following injection of antibodies in serum reaction in the body to infection reaction following vaccination Which term is correct for each of these numbers?

11. Immunity  →  11.2. Antibodies and vaccination

11. Immunity  →  11.1. The immune system

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38

The diagram shows a food web. seagull starfish herbivorous molluscs sea urchin barnacles crustaceans zooplankton algae detritus How many trophic levels are represented in the food web?

18. Classification, biodiversity and conservation  →  18.2. Biodiversity

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39

The diagram represents loss of energy from a food chain to decomposers, transfer of energy to the next trophic level and energy loss through respiration. All figures are in kJ m–2 y–1. 36 360 primary producers 3 600 herbivore carnivore 20 880 2 052 11 880 1 188 total energy of trophic level loss to decomposers respiratory loss What is illustrated by this diagram?

12. Energy and respiration  →  12.1. Energy

13. Photosynthesis  →  13.1. Photosynthesis as an energy transfer process

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40

The diagram represents part of the nitrogen cycle. Which process is carried out by nitrifying bacteria?

12. Energy and respiration  →  12.2. Respiration

7. Transport in plants  →  7.2. Transport mechanisms

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