IGCSE Limiting factors of photosynthesis

Identify the limiting factor of photosynthesis on a hot summer day in Shanghai

• Light intensity

• Concentration of carbon dioxide

• The availability of water

• Temperature

State the type of molecules that catalyse the reactions of photosynthesis

In the middle of the day in winter in Shanghai which factor is most likely to limit the rate of photosynthesis?

• Number of guard cells

• Light intensity

• Water availability

• Temperature

State the term for the pores found in the surface of the leaf that allow gas exchange to take place

What percentage of the Earth's atmosphere is carbon dioxide?

• 0.04%

• 0.4%

• 4%

• 40%

Why does the graph level off?

• Carbon dioxide is the limiting factor

• The stomata are not fully open

• Some factor other than the concentration of carbon dioxide is limiting

• The plant needs to be watered

State the organelle in the image

What factor is likely to limit the rate of photosynthesis very early in the morning in a Shanghai summer?

• Concentration of carbon dioxide

• Water availability

• Light intensity

• Temperature

There are chloroplasts in guard cells. How many layers of cells (tissues) will light need to pass through to reach the guard cells?

• 1

• 2

• 3

• 4

What prevents the loss of water from the upper surface of leaves?

• Upper epidermis

• Waxy cuticle

• Air spaces

• Palisade mesophyll