Topic 10 Practice Paper: Gas exchange and respiration — question paper

Section A: Multiple-choice questions[10 marks]

Choose one answer for each question. Each question is worth 1 mark.

1. 1

   The alveoli provide efficient gas exchange mainly because their walls are

   1. Acovered in cartilage
   2. Bvery thin with a large total surface area
   3. Clined with strong muscle
   4. Ddry to repel water
   ( )
2. 2

   Which sequence traces the path of air into the body?

   1. ABronchioles → bronchi → trachea → alveoli
   2. BAlveoli → bronchioles → trachea → bronchi
   3. CTrachea → alveoli → bronchi → bronchioles
   4. DTrachea → bronchi → bronchioles → alveoli
   ( )
3. 3

   Limewater surrounded by expired air turns

   1. Aclear and stays clear
   2. Bblue-black
   3. Cmilky or cloudy
   4. Dbright red
   ( )
4. 4

   When inhaling, the pressure inside the thorax

   1. Arises above atmospheric pressure
   2. Bfalls below atmospheric pressure
   3. Cstays equal to atmospheric pressure
   4. Dhas no relation to air movement
   ( )
5. 5

   During exercise, the brain increases breathing rate because it detects rising

   1. Aoxygen in the blood
   2. Blactic acid in the stomach
   3. Ccarbon dioxide in the blood
   4. Dwater vapour in the lungs
   ( )
6. 6

   Goblet cells protect the breathing system by

   1. Asecreting mucus that traps pathogens
   2. Bcontracting to cough
   3. Cproducing cartilage
   4. Dmanufacturing antibodies
   ( )
7. 7

   Which word equation is correct?

   1. Aglucose → carbon dioxide + water (aerobic)
   2. Bglucose + oxygen → lactic acid (aerobic)
   3. Cglucose + oxygen → carbon dioxide + water (aerobic)
   4. Dglucose + water → carbon dioxide + alcohol (yeast)
   ( )
8. 8

   Which products come from fermentation by yeast?

   1. Alactic acid only
   2. Boxygen and glucose
   3. Cprotein and water
   4. Dethanol (alcohol) and carbon dioxide
   ( )
9. 9

   A yeast suspension respires fastest at about 40 °C and slowly at 60 °C because at 60 °C its enzymes are

   1. Aworking faster than ever
   2. Bdenatured
   3. Cfrozen
   4. Ddigesting the glucose too quickly
   ( )
10. 10

    After intense exercise the oxygen debt is cleared when

    1. Athe liver aerobically respires the transported lactic acid
    2. Bthe muscles exhale the lactic acid
    3. Cthe kidneys store the lactic acid
    4. Dsweat removes the lactic acid through the skin
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided.

1. 11

   The diagram shows a section through part of the breathing system.

   1. (a)

      Name the structures that would be labelled: the windpipe, its two branches, and the air sacs at the end of the smallest branches.

      [2]
   2. (b)

      State two features of the air sacs that make them efficient exchange surfaces.

      [2]
   3. (c)

      Explain why a good blood supply increases the rate of gas exchange.

      [2]
2. 12

   A class compares inspired and expired air by bubbling each through limewater, and then studies ventilation. (Extended)

   1. (a)

      State the expected observation for each air sample.

      [1]
   2. (b)

      Explain the difference in oxygen and carbon dioxide content between the two samples.

      [2]
   3. (c)

      Describe what happens to the diaphragm and to the volume and pressure of the thorax when breathing out at rest.

      [3]
   4. (d)

      Explain one role of cartilage in the airway. (Extended)

      [1]
3. 13

   An athlete trains by repeating sprints. During each sprint her leg muscles rely partly on anaerobic respiration. (Extended)

   1. (a)

      Write the word equation for respiration in her leg muscles during the sprint.

      [1]
   2. (b)

      Explain why her muscles could not rely on this type of respiration indefinitely.

      [2]
   3. (c)

      Describe how her body removes the lactic acid after the race.

      [3]
   4. (d)

      During recovery, why does her breathing rate remain above resting level?

      [1]