Science 8 · Unit 1: Respiration · Cambridge Lower Secondary Science Stage 8

Questions

1. 1. Which component of blood is a liquid?

   • red blood cells
   • platelets
   • white blood cells
   • plasma
   Check

2. 2. Which blood cells have a nucleus?

   • white blood cells
   • red blood cells
   • both red and white
   • plasma
   Check

3. 3. What do red blood cells transport?

   • nutrients only
   • antibodies
   • oxygen from the lungs to respiring cells
   • carbon dioxide only
   Check

4. 4. What is the red pigment in red blood cells called?

   • plasma
   • cytoplasm
   • chlorophyll
   • haemoglobin
   Check

5. 5. What is the function of white blood cells?

   • to carry glucose
   • to carry oxygen
   • to make the blood red
   • to destroy pathogens
   Check

6. 6. What does plasma transport?

   • blood cells, nutrients like glucose, and carbon dioxide
   • only antibodies
   • only oxygen
   • nothing
   Check

7. 7. What are pathogens?

   • cells that carry oxygen
   • nutrients in food
   • microorganisms that cause disease
   • parts of the lungs
   Check

8. 8. What are antibodies?

   • chemicals made by white blood cells that attach to and kill pathogens
   • liquid in blood
   • red pigments
   • a type of food
   Check

9. 9. How else can white blood cells kill pathogens?

   • by taking them into their cytoplasm and digesting them
   • by turning red
   • by carrying oxygen to them
   • by dissolving in plasma
   Check

10. 10. Which are the most abundant cells in blood?

    • plasma cells
    • red blood cells
    • nerve cells
    • white blood cells
    Check

11. 11. Why do red blood cells have no nucleus?

    • to leave more room for haemoglobin
    • so they can divide faster
    • so they can fight germs
    • to make them heavier
    Check

12. 12. Predict what happens to red blood cell count in rats taken to high altitude.

    • It stays the same.
    • It drops to zero.
    • It decreases.
    • It increases, because there is less oxygen in the air.
    Check

13. 13. In the rat experiment, what was the independent variable?

    • the number of days only
    • the type of rat food
    • the red blood cell count
    • the altitude (sea level or high altitude)
    Check

14. 14. High-altitude rats' count went from 6.5 on day 1 to 11.5 on day 20. What was the increase?

    • 18.0
    • 6.5
    • 5.0
    • 11.5
    Check

15. 15. What is the mean rate of increase per day from day 1 to day 20 if the increase is 5.0?

    • 20 per day
    • 1 per day
    • about 0.26 per day
    • 5.0 per day
    Check

16. 16. The rats are taken back to sea level. What happens to their red blood cell count?

    • It gradually falls back to normal.
    • It keeps rising.
    • It doubles.
    • It drops to zero.
    Check

17. 17. Oxygen combines with haemoglobin in red blood cells. What does it form?

    • oxyhaemoglobin
    • plasma
    • haemoglobin oxide
    • glucose
    Check

18. 18. Why do scientists think red blood cells have no mitochondria?

    • so they don't use up the oxygen they carry
    • so they can divide quickly
    • so they can carry more glucose
    • so they can make antibodies
    Check

19. 19. A white blood cell pushes out its cytoplasm, captures a bacterium and digests it. What is this called?

    • phagocytosis
    • respiration
    • photosynthesis
    • diffusion
    Check

20. 20. What colour is blood plasma?

    • bright red
    • clear like water
    • very pale yellow
    • dark blue
    Check