T1.4.4 Leaf stomata and gas exchange in plants Quiz: KS3 Biology, Unit 1

The 20 questions

1. What are stomata?

   • Root hairs for absorbing minerals and water from the soil
   • Large tubes in the stem that carry water up from the roots
   • Cells that make glucose only in the leaves and stem
   • Small pores in the surface of leaves that allow gases in and out

2. What are guard cells?

   • Cells that store starch and sugars in the leaf
   • Cells that surround each stoma and control its opening
   • Cells in the roots that absorb water and minerals
   • Cells that digest food and release enzymes in the leaf

3. What is the main function of stomata?

   • To store starch for the plant to use in winter
   • To allow gas exchange between the leaf and the air
   • To absorb water from the soil through the root hairs
   • To produce sugar for the plant to store as starch

4. Which gas is released from leaves through stomata during photosynthesis?

   • Oxygen
   • Methane
   • Carbon dioxide
   • Nitrogen

5. What is transpiration?

   • The movement of sugars from the leaves down to the roots
   • The breakdown of glucose to release energy in the cells
   • The absorption of minerals by the roots from the soil
   • The loss of water vapour from the leaves through stomata

6. Why do stomata close at night?

   • To produce more glucose overnight in the dark
   • To let more oxygen in so respiration can continue
   • To reduce water loss, because photosynthesis does not happen
   • To absorb more sunlight to keep the leaf warm

7. Where are most stomata found on a leaf?

   • The stem
   • The roots
   • The lower surface
   • The top surface only

8. Why does a leaf need a large surface area?

   • To make seeds and spread them more widely
   • To grow taller and reach more light
   • To store large amounts of water in the leaf
   • To absorb more light and exchange gases

9. A plant is placed in a dry, windy place. What would most likely happen to its stomata?

   • They would close to reduce water loss
   • They would open widely to lose more water
   • They would produce more oxygen
   • They would stop working altogether

10. Which path does water vapour take out of a leaf?

    • Through the stomata
    • Through the bark
    • Through the roots
    • Through the cell wall only

11. Why does opening stomata both help photosynthesis and increase water loss?

    • Gases diffuse in both directions, so carbon dioxide enters as water vapour leaves
    • Stomata have no role in water loss, since water diffuses through the cuticle
    • Stomata only let water out of the leaf and never let gases in
    • Stomata only let carbon dioxide in, so the leaf keeps all its water

12. What happens to guard cells when they take in water and swell?

    • They close the stoma
    • They transport minerals
    • They produce glucose
    • They open the stoma

13. A student covers the lower surface of a leaf with petroleum jelly. Which effect is expected?

    • More oxygen enters the leaf through the covered surface
    • The leaf produces more starch in the covered area
    • Photosynthesis increases on the covered lower surface
    • Less water vapour is lost from the lower surface

14. Which term describes the diffusion of gases in and out of a leaf?

    • Ventilation
    • Digestion
    • Excretion
    • Gas exchange

15. Why do cacti have few stomata?

    • To grow faster in dry and sandy soil
    • To absorb more light in the desert sun
    • To produce more carbon dioxide each day
    • To reduce water loss in dry conditions

16. Which statement correctly links stomata and transpiration?

    • Stomata stop transpiration completely during the daytime hours
    • Transpiration happens mainly through stomata, as water vapour diffuses out
    • Transpiration happens only through the roots of the plant
    • Stomata are not involved in transpiration at all, only in growth

17. What are the air spaces inside a leaf for?

    • To allow gases to move to the cells
    • To absorb light for the cells in the leaf
    • To carry sugar to the roots of the plant
    • To hold pores in the roots for water

18. Why does a plant wilt on a hot day if its stomata stay open?

    • Stomata make the roots stronger
    • Water enters faster through leaves than roots
    • Water is lost faster than the roots can replace it
    • Heat makes the cell walls grow

19. Why do guard cells need to change shape?

    • To make glucose more quickly in the light and dark
    • To transport minerals up to the roots and the stems
    • To open and close the stoma and control gas exchange and water loss
    • To produce cellulose for the cell walls of the leaf

20. Which part of a leaf contains the stomata?

    • The epidermis
    • The palisade cells only
    • The phloem
    • The xylem

Related quizzes

• Cells and light microscopy Quiz · T1.1.1 · 20 questions
• Cell parts and their functions Quiz · T1.1.2 · 20 questions
• Plant and animal cells compared Quiz · T1.1.3 · 20 questions
• Diffusion in and between cells Quiz · T1.1.4 · 20 questions
• Unicellular organisms and their adaptations Quiz · T1.1.5 · 20 questions
• From cells to organisms Quiz · T1.1.6 · 20 questions
• The human skeleton and its functions Quiz · T1.2.1 · 20 questions
• Biomechanics: muscles, skeleton and force Quiz · T1.2.2 · 20 questions
• Muscles and antagonistic pairs Quiz · T1.2.3 · 20 questions
• A healthy human diet Quiz · T1.3.1 · 20 questions