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

Questions

1. 1. What is respiration?

   • a chemical reaction in cells that releases energy from food
   • digesting food
   • pumping blood
   • breathing in and out
   Check

2. 2. What is the word equation for aerobic respiration?

   • glucose → oxygen + water
   • oxygen + water → glucose
   • carbon dioxide + water → glucose + oxygen
   • glucose + oxygen → carbon dioxide + water
   Check

3. 3. Where in a cell does aerobic respiration happen?

   • in the cell wall
   • in the nucleus
   • in the chloroplasts
   • in the mitochondria
   Check

4. 4. Is respiration the same as breathing?

   • Yes, they are the same.
   • No, respiration is only in lungs.
   • Yes, both happen only in the lungs.
   • No, breathing moves air; respiration releases energy in cells.
   Check

5. 5. Which living things respire?

   • only humans
   • all living things
   • only animals
   • only plants
   Check

6. 6. What is yeast?

   • a mineral
   • a type of sugar
   • a plant seed
   • a living microorganism
   Check

7. 7. What piece of apparatus does Sofia need to measure yeast respiring?

   • a ruler
   • a forcemeter
   • a magnet
   • a thermometer
   Check

8. 8. Predict what happens to the temperature of yeast and sugar in an insulated cup.

   • It freezes.
   • It rises, because respiration releases energy as heat.
   • It stays the same.
   • It falls.
   Check

9. 9. Why use an insulated cup?

   • to stop the yeast breathing
   • to stop heat escaping so the temperature change can be measured
   • to make the yeast heavier
   • to keep light out
   Check

10. 10. What important part has Sofia missed from her experiment?

    • more yeast
    • a bigger cup
    • a control - a cup with sugar solution but no yeast
    • a second thermometer for the room only
    Check

11. 11. How should you read a thermometer?

    • from above at an angle
    • with your eyes level with the top of the liquid
    • after taking it out of the liquid
    • with it resting on the bottom of the cup
    Check

12. 12. To test 'the more sugar, the faster yeast respires', what is the independent variable?

    • the temperature rise
    • the concentration of sugar
    • the cup size
    • the volume of yeast
    Check

13. 13. In that test, what is the dependent variable?

    • the cup
    • the rate of temperature rise
    • the type of thermometer
    • the amount of sugar
    Check

14. 14. Which gas does respiration produce?

    • carbon dioxide
    • hydrogen
    • oxygen
    • nitrogen
    Check

15. 15. Why do cells need energy from respiration?

    • to stop growing
    • to store carbon dioxide
    • for growth, movement and keeping warm
    • to make oxygen
    Check

16. 16. Neurones contain more mitochondria than cheek cells. Why?

    • They need more oxygen to store.
    • They make glucose for the body.
    • They are much smaller cells.
    • They need more energy, to send impulses.
    Check

17. 17. Two insulated flasks hold dead peas and live, germinating peas. Which flask gets warmer?

    • neither changes
    • the live, germinating peas
    • the dead peas
    • both the same
    Check