Gas Exchange in Humans (Cambridge (CIE) IGCSE Biology): Exam Questions

Exam code: 0610 & 0970

3 hours41 questions

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1
1 mark

What makes the alveoli suitable as a gas exchange surface in mammals?

 

a dense capillary network

large total surface area

A

X

X

B

X

C

X

D

    2
    1 mark

    Which of the following sequences show the correct path of oxygen as it enters the lungs?

    • trachea → bronchiole → bronchus → alveolus

    • trachea → bronchus → bronchiole → alveolus

    • alveolus → bronchus → bronchiole → trachea

    • alveolus → bronchiole → bronchus → trachea

    3
    1 mark

    What is the approximate percentage of carbon dioxide in expired air?

    • 16 %

    • 0.04 %

    • 4 %

    • 21 %

    4
    1 mark

    Extended

    The image below shows some cells found in the trachea.

    11--image-8-ciliated-cells

    What is the function of the part labelled K?

    • Increasing surface area

    • Gas exchange

    • Moving mucus

    • Trapping bacteria

    5
    1 mark

    Name the structures shown in the diagram.

    lungs

     

    W

    X

    Y

    Z

    A

    larynx

    trachea

    bronchi

    bronchioles

    B

    trachea

     larynx

    bronchioles

    bronchi

    C

    bronchi

    trachea

    bronchioles

    larynx

    D

    larynx

    bronchi

    larynx

    bronchioles

      1
      1 mark

      The diagram below shows a cross-section through an alveolus and a capillary.

      11--image-6-alveolus-and-capillary

      Why does oxygen move from P to Q?

      • The concentration of carbon dioxide is lower in the alveolus than in the blood.

      • The concentration of oxygen in the blood is lower than in the air in the capillary.

      • Oxygen must replace carbon dioxide.

      • The concentration of oxygen in the blood is lower than the air in the alveolus.

      2
      1 mark

      Some amphibians, such as frogs, can use their skin as a gas exchange surface.

      What are the most likely characteristics of the surface of the skin in these amphibians?

       

      surface area

      type of skin

      A

      small

      thick

      B

      large

      thick

      C

      small

      thin

      D

      large

      thin

        3
        1 mark

        Extended

        When the diaphragm relaxes and internal intercostal muscles contract, how does the volume and pressure inside the thorax change?

         

        pressure

        volume

        A

        decreases

        decreases

        B

        decreases

        increases

        C

        increases

        decreases

        D

        increases

        increases

          4
          1 mark

          Compared to the composition of atmospheric air, the air exhaled by a man contains:

          • more water vapour, more carbon dioxide.

          • more water vapour, less carbon dioxide.

          • less water vapour, more carbon dioxide.

          • less water vapour, less carbon dioxide.

          5
          1 mark

          Extended

          The diagram shows the composition of four samples of air (O2 = oxygen, CO2 = carbon dioxide, N2 = nitrogen).

          11--image-2-composition-of-air

          Which sample is inspired air and which sample is expired air?

           

          inspired air

          expired air

          A

          R

          S

          B

          P

          R

          C

          Q

          P

          D

          S

          R

            6
            1 mark

            What are the approximate percentages of oxygen and carbon dioxide in inspired air?

            percentage of oxygen

            percentage of carbon dioxide

            A

            16

            4.00

            B

            16

            8.00

            C

            21

            0.04

            D

            21

            4.00

              7
              1 mark

              The diagrams show the depth and rate of breathing in a person at 12:00 and 13:00.

              Two line graphs show volume changes over 70 seconds at 12:00 and 13:00; first graph peaks at 0.5 dm³, while the second has higher fluctuations.

              What happens to the person’s breathing between 12:00 and 13:00?

              depth of breathing 

              rate of breathing

              A

              decreases 

              decreases 

              B

              decreases 

              increases

              C

              increases

              decreases 

              D

              increases

              increases

                8
                1 mark

                 A person lives in a climate where the air is very dry. 

                Which row correctly compares inspired air with expired air for this person?

                inspired air

                expired air

                A

                higher carbon dioxide concentration

                higher oxygen concentration

                B

                lower water vapour concentration

                higher carbon dioxide concentration

                C

                lower oxygen concentration

                higher water vapour concentration

                D

                lower carbon dioxide concentration

                lower water vapour concentration

                  9
                  1 mark

                  Which row shows a change that occurs during ventilation?

                  process

                  thorax pressure

                  thorax volume

                  air movement

                  A

                  expiration

                  decreases

                  increases

                  in

                  B

                  expiration

                  increases

                  decreases

                  out

                  C

                  inspiration

                  decreases

                  increases

                  out

                  D

                  inspiration

                  increases

                  decreases

                  in

                    10
                    1 mark

                    Which sequence of changes takes place when we breathe in?

                    • diaphragm contracts →  volume of thorax increases → pressure in lungs decreases

                    • diaphragm contracts → volume of thorax increases → pressure in lungs increases

                    • diaphragm relaxes  → volume of thorax increases → pressure in lungs decreases

                    • diaphragm relaxes → volume of thorax increases →  pressure in lungs
                      increases

                    11
                    1 mark

                    What do the external intercostal muscles do during inhalation?

                    • pull ribs downwards

                    • pull ribs upwards and outwards

                    • push air into lungs

                    • produce mucus

                    12
                    1 mark

                    Why does breathing rate increase during exercise?

                    • oxygen concentration in blood increases

                    • oxygen concentration in blood decreases

                    • carbon dioxide concentration in blood increases

                    • carbon dioxide concentration in blood decreases

                    13
                    1 mark

                    The diagram shows a representation of the human gas exchange system.

                    Diagram of human lungs and trachea, labelled numerically with bronchial tubes branching into lung sections, and diaphragm shown below.

                    Which row correctly identifies the labelled structures?

                    Structure 1

                    Structure 2

                    Structure 3

                    Structure 4

                    A

                    Oesophagus

                    Bronchus

                    Diaphragm

                    Alveolus

                    B

                    Trachea

                    Bronchiole

                    Intercostal muscle

                    Blood vessel

                    C

                    Trachea

                    Bronchus

                    Diaphragm

                    Alveolus

                    D

                    Bronchus

                    Bronchiole

                    Abdominal muscle

                    Capillary

                      1
                      1 mark

                      Extended

                      Which of the following correctly describes the actions of the intercostal muscles and the diaphragm when we breathe in?

                       

                      external intercostal muscles

                      internal intercostal muscles

                      diaphragm

                      A

                      contract

                      relax

                      domed

                      B

                      contract

                      relax

                      flat

                      C

                      relax

                      contract

                      domed

                      D

                      relax

                      contract

                      flat

                        2
                        1 mark

                        The diagram shows part of the structure of a human lung.

                        Where would the concentration of carbon dioxide be highest?

                        11--image-3-alveolus11--image-3-alveolus
                          3
                          1 mark

                          Extended

                          The diagram below illustrates the changes in air pressure taking place inside the lungs during a complete cycle of breathing. Atmospheric pressure is 101 kPa.

                          Graph showing pressure in lungs over time in kPa. Peaks at B above 102, dips at D below 101. Points A, C marked with arrows on the curve.

                          At which point on the diagram does the process of inhalation start?

                            4
                            1 mark

                            Extended

                            A person exhales, and the air from their lungs is collected and placed in a gas jar. A second gas jar contains normal atmospheric air. A candle is set alight and is placed inside each gas jar as shown. The time taken for each flame to go out is measured with a stopwatch.

                            -11--image-7-gas-jars

                            The table shows the results of this experiment.

                            gas jar

                            time for candle flame to go out /s

                            1

                            7

                            2

                            12

                            Which of the following is a correct explanation for the difference between the results in jars 1 and 2?

                            • Jar 1 contains atmospheric air which has less oxygen than exhaled air.

                            • Jar 1 contains exhaled air which has less oxygen compared to atmospheric air.

                            • Jar 2 contains atmospheric air which has more carbon dioxide than exhaled air.

                            • Jar 2 contains exhaled air which has more carbon dioxide than oxygen in it.

                            5
                            1 mark

                            Which of the following helps carbon dioxide to be excreted rapidly into the alveoli from the blood in the lungs?

                            1. Inhaled air has a lower concentration of carbon dioxide than the blood constantly pumping through the lungs.

                            2. Alveoli have thick walls and a large surface area.

                            3. Alveoli have thin walls and a large surface area.

                            4. The concentration of carbon dioxide in the blood is lower than in the alveoli.

                            • 1, 2 & 4 only

                            • 3 only

                            • 1 & 3 only

                            • 3 & 4 only

                            6
                            1 mark

                            Below are statements about the features of gas exchange surfaces in humans.

                            1. Gas exchange surfaces have a large surface area to maximise the rate of diffusion

                            2. Gas exchange surfaces have a thick surface to prevent damage from the constant movement of air

                            3. Gas exchange surfaces have a good blood supply to remove gases that have diffused across the surface

                            4. Gas exchange surfaces are well ventilated to increase the concentration of carbon dioxide in the alveoli

                            Which statements are correct?

                            • 1 only

                            • 1, 2 and 3 only

                            • 1 and 3 only

                            • 1, 3 and 4 only

                            7
                            1 mark

                            Extended

                            The graph shows changes in the volume of air in the lungs of a person at rest, over a period of 30 seconds.

                            -11--image-4-air-in-lungs

                            Which graph below shows the changes in the volume of air in the lungs for the same person immediately after they have done a few minutes of vigorous exercise?

                            Four graphs labelled A to D show volume of air in lungs over time. A and D have tight peaks, B has broader peaks, and C has smaller fluctuations.
                              8
                              1 mark

                              Which row correctly describes the composition of expired air compared to inspired air?

                              Oxygen

                              Carbon dioxide

                              Water vapour

                              A

                              higher

                              higher

                              higher

                              B

                              lower

                              higher

                              higher

                              C

                              lower

                              lower

                              higher

                              D

                              higher

                              lower

                              lower