More on Exchanging Substances Flashcards
The structure of leaves lets gases diffuse in and out of what?
Cells.
What does carbon dioxide do in a leaf?
Diffuses into the air spaces within the leaf, and then it diffuses into the cells where photosynthesis happens.
What is the underneath of a leaf?
It is an exchange surface that is covered in little holes called stomata which the carbon dioxide diffuses in through.
What 2 things diffuse out of the stomata?
Oxygen and water vapour.
What is a factor about the leaf that increases the area of the exchange surface?
The flattened shape of the leaf.
What do the walls of the cells inside the leaf form?
Another exchange surface - the air spaces inside the leaf increase the area of this surface so there’s more a chance for CO2 to get into the cells.
What is the gas exchange surface in fish?
Gills.
How does water enter and leave a fish?
In through the mouth and out through the gills.
What happens when water enters a fish?
Oxygen diffuses from the water into the blood in the gills and carbon dioxide diffuses from the blood into the water.
What is a gill filament?
A thin plate which gives a big surface area for exchange of gases.
What are gill filaments covered in?
Lamellae which increases the surface area even more.
What is in lamellae?
Blood capillaries to speed up diffusion and lamellae also has a thin surface area of cells to minimise the distance that the gases have to diffuse.
How is there a larger concentration gradient between the water and blood?
Because blood flows through the lamellae in one direction and water flows over in the opposite direction.
What is the difference between the concentration of oxygen in water and blood.
It is higher in the water than it is in blood so as much oxygen as possible diffuses from water into the blood.
