Component 3.1 - Gas Exchange and Photosynthesis In Leaves Flashcards
How do plants get carbon dioxide for photosynthesis?
Some of the carbon dioxide they need for photosynthesis is provided by respiration but most diffuses into the leaves from the atmosphere.
What happens to the oxygen produced by photosynthesis?
Some of the oxygen they produce by photosynthesis is used in respiration but most diffuses out of the leaf.
Describe the input and output of gases in plants during the day
During the day the rate of photosynthesis is faster than the rate of respiration. This means more oxygen is produced in photosynthesis than is used in respiration. So, overall the gas released is oxygen.
Describe the input and output of gases in plants during the night
At night photosynthesis does not happen, only respiration, so no oxygen is produced. So the gas that is released is carbon dioxide.
Describe how gases get into the leaf
Gases diffuse through the stomata down a concentration gradient. The gases inside the sub-stomatal chamber diffuse through intercellular spaces in the spongy mesophyll.
How does a large surface area of a leaf help with gas exchange?
There is room for many stomata
How does a large surface area help with photosynthesis?
The leaf can capture as much light as possible
How does the cuticle being transparent help with photosynthesis?
Light can penetrate to the mesophyll
How does elongated palisade cells help with photosynthesis?
The leaf can accommodate a large number of them
How does palisade cells having lots of chloroplasts help with photosynthesis?
They can capture as much light energy as possible
How does the fact that chloroplasts can move within mesophyll cells help with photosynthesis?
They move into bets positions for maximum absorption of light
How do air spaces in the spongy mesophyll help with gas exchange?
They allow oxygen and carbon dioxide to diffuse between the stomata and the cells
How do air spaces in the spongy mesophyll help with photosynthesis?
Allows carbon dioxide to diffuse to photosynthesising cells
How do stomata pores help with gas exchange?
They allow gas exchange in and out of the leaf
