T1.4.1 The human gas exchange system Quiz: KS3 Biology, Unit 1

The 20 questions

1. What is the main function of the alveoli?

   • Exchange of oxygen and carbon dioxide with the blood
   • Pumping air into and out of the lungs with the ribs
   • Filtering waste and urea from the blood
   • Storing bile and releasing it into the gut

2. Which tube carries air from the throat towards the lungs?

   • Aorta
   • Oesophagus
   • Urethra
   • Trachea

3. What do the bronchi do?

   • Exchange gases with the blood in the alveoli
   • Make mucus that traps dust in the airways
   • Carry air from the trachea into each lung
   • Pump blood around the body from the lungs

4. Why are alveoli well adapted for gas exchange?

   • They are very small and stiff to hold their shape
   • They have no blood supply, so gases diffuse slowly
   • They are thick and dry to stop gases escaping
   • They have a large surface area and thin walls

5. What do the cilia in the airways do?

   • Produce oxygen for the blood in the lungs
   • Pump air in and out of the lungs during breathing
   • Move mucus and trapped dust up and out of the lungs
   • Break down bacteria in the airways with acid

6. What is the job of the mucus lining the airways?

   • Traps dust and microbes
   • Produces the enzyme amylase
   • Absorbs oxygen into the blood
   • Stops carbon dioxide leaving the lungs

7. Why are the capillaries around each alveolus important?

   • They absorb bile and carry it back to the liver
   • They make the alveoli stronger and less elastic
   • They carry air from the alveoli up to the heart
   • They carry blood close to the air for gas exchange

8. What is the function of the diaphragm in breathing?

   • It contracts and relaxes to change the volume of the chest
   • It produces mucus that traps dust in the airways
   • It filters waste from the blood before it reaches the heart
   • It digests food in the stomach and intestine

9. Which feature of the alveoli keeps the surface moist for gas exchange?

   • Gases dissolve in the moist lining before they diffuse
   • The alveoli are covered in a thick bony layer
   • The lungs are made of dry cartilage and bone only
   • The alveoli produce bile to keep the lining wet

10. Why do alveoli have a good blood supply?

    • To carry oxygen away and bring carbon dioxide to the lungs
    • To make the lungs heavier so they hold more air
    • To store air and carbon dioxide in the blood
    • To produce bile that is carried in the blood to the lungs

11. Which airway is the smallest tube that ends in the alveoli?

    • Bronchioles
    • Trachea
    • Bronchi
    • Diaphragm

12. Why is the trachea supported by rings of cartilage?

    • To produce mucus that lines the airway
    • To keep the airway open and stop it collapsing
    • To make it stretch and shrink with each breath
    • To absorb carbon dioxide from the air

13. Which gas diffuses from the alveoli into the blood?

    • Nitrogen
    • Oxygen
    • Carbon dioxide
    • Water vapour

14. Why do alveoli form as many small air sacs rather than one large one?

    • To give a large total surface area in a small space
    • To trap dust and bacteria in each small sac
    • To store more carbon dioxide in a small space
    • To make breathing louder and easier to hear

15. Why does the gas exchange system need a large total surface area?

    • To allow enough oxygen to diffuse into the blood for the body's needs
    • To store carbon dioxide until it can be breathed out
    • To block dust and bacteria from entering the lungs at all
    • To make breathing louder and more noticeable to others

16. Which order shows the path of oxygen from the air into the blood?

    • Trachea, alveoli, bronchi, bronchioles, then the blood
    • Mouth or nose, trachea, bronchi, bronchioles, alveoli, blood
    • Alveoli, bronchioles, trachea, mouth, then the blood
    • Nose, bronchi, alveoli, trachea, bronchioles, then blood

17. Which organs carry out gas exchange in humans?

    • The lungs
    • The kidneys
    • The heart
    • The liver

18. Why does the body remove carbon dioxide through the lungs?

    • It is made by the alveoli
    • It is needed for photosynthesis in the lungs
    • It is a waste gas made during respiration
    • It is stored for later use

19. What does the term gas exchange surface mean?

    • A surface where gases diffuse between the air and the blood
    • A surface that filters waste and urea from the blood
    • A surface that stores water for the cells to use
    • A surface that produces gases for the body to use

20. Which two gases are exchanged in the lungs?

    • Hydrogen and oxygen
    • Nitrogen and carbon monoxide
    • Oxygen and carbon dioxide
    • Oxygen and water

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