Gas Exchange in the Leaf of a Plant Flashcards
What is found on the lower side of the leaf?
Stomata
What is the singular of stomata?
Stoma
What is the stoma?
The gap that is formed by two guard cells.
What occurs at the stomata?
Gas exchange.
How does gas exchange occur at the stomata?
Carbon dioxide diffuses in at the stomata and enters into the spongy mesophyll. It then diffuses up into the palisade mesophyll.
How is the spongy mesophyll good for gas exchange?
There is a lot of space for gas to diffuse in.
Where does most photosynthesis occur?
The palisade mesophyll as it is closer to the top surface and thus receives more direct sunlight.
What occurs at the vascular bundle?
Xylem and Phloem
What happens at the xylem?
Water is transported and mineral ions are dissolved in the process of transpiration.
What happens at the phloem?
Sugar is transported in the process of translocation.
Describe the structure of the palisade mesophyll. Why is that important?
Narrower and longer shaped cells so you can pack a lot of cells containing lots of chloroplasts. Thus, chlorophyll which will maximise light absorption for photosynthesis.
What diffuses in and what diffuses out of the stomata?
Carbon dioxide diffuses in, oxygen diffuses out.
Why is carbon dioxide diffused in rather than out?
Carbon dioxide is needed for photosynthesis.
How is water loss by evaporation reduced in a plant?
Stomata close at night when photosynthesis wouldn’t be able to occur.
What are xerophytic plants adapted to do ?
Survive in environments with harsh conditions such as limited water.
How does the adaptation of curled leaves in xerophytic plants help them?
The curled leaves trap moisture to increase local humidity. Water potential gradient from inside the plant to the outside is reduced.
How does the adaptation of hairs in xerophytic plants help them?
Trap water that is being evaporated from the leaf to trap the moisture to increase local humidity. Water potential gradient reduced, thus less evaporation or transpiration.
How does the adaptation of sunken stomata in xerophytic plants help them?
Helps to trap moisture to increase local humidity leading to less evaporation.
What 5 adaptations do xerophytic plants have to help them?
Thicker cuticle
Longer root network
Sunken stomata
Curled Leaves
Hairs
How does the adaptation of thicker cuticles in xerophytic plants help them?
Reduce evaporation
How does the adaptation of longer root network in xerophytic plants help them?
To reach water at further distances.
How is a large surface area in plants established?
Many stomata.
How is a short diffusion distance established?
Thin leaf.
