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Flashcards in Exchnaging Substances Deck (20):

What is diffusion ?

The spreading out of particles from a area of high concentration to an area of low concentration


Name the substances that can diffuse through a cell mebrane

-amino acids


Name the substance that can’t diffuse through a cell membrane



What type of molecules move by osmosis



What is osmosis ?

The movement of water molecules across a partially permeable membrane in from aRegion of high concentration to low concentration


What is active transport ?

The movement of substances from a lower concentration to high concentration against a concentration gradient


What is the difference between diffusion and active transport ?

-Active transport requires energy

- Diffusion is from a high concentration to a low concentration whereas active transport it on the loo concentration to high concentration


How are alveoli adapted for gas exchange ?

-large surface are
-thin walls
-good blood supply
-moist lining


How are the villi in the small intestine adapted for absorbing digested food ?

-single layer of surface cells

-good blood supply


How are leaves adapted to maximise the amount of carbon diode that gets in there cells ?

It is covered in little holes called stomata


Where does diffusion happen?

In solutions and gases this is because the particles are free to move about randomly


How can we increase the rate of diffusion

-A bigger concentration gradient

-Higher temperature particles have more energy

-bigger surface area


What is a partially permeable membrane in?

The membrane with very small holes in it


Where is active transport used?

-when mineral ions need to be absorbed into plants through root hair cells

- When sugar molecules need to be absorbed from lower concentrations in the goat to the blood which has a higher sugar concentration


How are exchange services adapted to maximise effectiveness?

-thin membrane so there is only a short distance to diffuse

-large surface area so lots of substance can diffuse at once

-Lots of blood vessels to get stuff into and out of the blue quickly


How are you gills adapted for gas exchange?

-Large surface area

-covered in Gill filaments which are covered in Lamelle which increases of Surface area even more

-lots of blood can capillaries

-thin surface layer to minimise the distance


Other than diffusion I want to processors do you substances move across exchange surfaces?

Active transport and osmosis


Name the exchange surfaces in human

Alveoli In the lung and villi in the Smalling intestine


Explain how the structure of the villi is related to their function?

-The increased surface area to maximise absorption

-they have a thin wall to reduce distance of diffusion

-they have a good blood supply for the uptake of substances


Suggest how the products of digestions move into the blood?

By diffusion down the concentration gradient into the blood

and by active transport against their concentration gradient