Diffusion

Question 0

Explain facilitated diffusion?

Answer 0

Passive process
Relies on kinetic energy
Uses protein channels
Allows water soluble ions to pass through 
Channels only open for specific ions

Question 1

What’s the formula for diffusion?

Answer 1

Surface area times diff in concentration

Divided by length of diffusion pathway

Question 2

How does diffusion maintain absorption?

Answer 2

Diffusion is constantly taking on place so concentration gradient is maintained
Villi have muscles that contract mixing the contents of small intestine to maintain conc gradient

Question 3

What are the functions of phospholipids in the cell surface membrane?

Answer 3

Make the membrane flexible
Allow lipid soluble substances to enter and leave cell
Prevent water soluble substances entering and leaving

Question 4

What do extrinsic proteins do?

Answer 4

Provide mechanical support to the membrane

Question 5

What do intrinsic proteins do?

Answer 5

Transport water soluble material across

Some are enzymes

Question 6

What factors effect diffusion?

Answer 6

Concentration gradient
Area over which diffusion takes place (larger the area the faster)
Thickness of exchange surface

Question 7

How is the diffusion gradient maintained in and out of the leaf?

Answer 7

By mitochondria carrying out respiration

By chloroplasts carrying out photosynthesis