Gas Exchange, Lungs and Breathing

Through which structures does gas diffuse in and out of a leaf?

• Palisade mesosphyll

• Lower epidermis

• Waxy cuticle

• Stomata

Why are stomata mostly on the underside of a leaf?

• To prevent rain getting in

• Because the CO₂ concentration is higher there

• To reduce water loss

• This is not true

During which part of the day does a plant need oxygen?

• Night time

• Day time

• All the time

• Never

During which part of the day does a plant need CO₂?

• Day time

• Night time

• All the time

• At midday only

By which process does CO₂ get into a leaf?

• Active transport

• Diffusion

• Breathing

• Wind

Which cells can open and close the stomata?

• Guard cells

• Keeper cells

• Palisade cells

• Cuticle cells

Which leaf feature enables gases to diffuse from the stomata to the palisade cells?

• Guard cells

• Spongy mesophyll

• Upper epidermis

• Phloem

Which of these are adaptations of a leaf for gas exchange?

• Large surface area

• Thin leaf

• Good sap supply

• Breathing

Which types of organisms have low surface area to volume ratios?

• Big ones

• Small ones

• Long thin ones

• Furry ones

Why don't bacteria need lungs or gills?

• They have a high enough surface area to volume ratio

• They don't need any oxygen

• They don't do respiration

• They make their own oxygen