Topic 1 Exchanging Substances Flashcards
How are alveoli specialised to maximise diffusion of O2 and CO2
Enormous surface area
Moist lining for dissolving gases
Very thin walls short diffusion pathway
Good blood supply
Where are villi found
Villi are found in the small intestine
How do villi help digested food absorbed more quickly into the blood
Increase surface area
A single layer of surface cells
Very good blood supply to assist quick absorption
Where does carbon dioxide diffuse in within the leaf
Into air spaces within the leaf and then diffuses into the cells where photosynthesis happens
What is the leafs structure adapted for
For the carbon dioxide to be diffused into to the cells
What is the underneath or a leaf
An exchange surface covered in stomata
What diffuses out of the stomata
Oxygen and water vapour
What are the stomata controlled by
Guard cells
What would happen without the guard cells
The plant would wilt because too much of the water vapour would be lost through the stomata
What makes the exchange surface of a leaf more effective
The flattened shape of the leaf increases the area
What do the walls of the cells inside the leaf create
Another exchange surface
What makes the exchange surface in the leaf more effective
The air spaces inside the leaf increase the surface area so there is more chance for Carbon to get in the cells
What does the water vapour escape by
Diffusion because there is a lot of it inside the leaf and less of it It in the air outside
What are the gills
The gas exchange surface for fish
How does the gas exchange happen in fish
The water enters the fish through its mouth and passes through the gills
As this happens oxygen diffuses from the water into the blood in the gills and the CO2 diffuses from the blood into the water
