Biology Unit 2 Topic 7: Facilitated Diffusion

facilitated diffusion

diffusion of molecules through the membrane via transport proteins doen the concentration gradient (passive transport)

rate increases for small ions, water, carbs

carrier proteins

type of transport protein used in facilitated diffusion that undergoes conformation changes for substances to pass

Channel Protein

a type of transport protein used in facilitated diffusion that provides a channel for molecules and ions to pass

hydrophilic

gated channels that only allow passage when there is a stimulus

Aquaporins

a specific channel proteins in facilitated diffusion that only allows the passage of water

Is facilitated diffusion a type of active or passive transport? Why?

passive

it moves down the concentration gradient and requires NO energy

The 2 types of transport proteins

carrier and channel

2 ways water can pass through the cell membrane

facilitated diffusion through aquaporins

osmosis

How does facilitated diffusion affect the rate of diffusion?

increases it for small ions, water, and carbs

Predict the effect on a cell if there was a mutation that changed the amino acid sequence of the proteins that make up aquaporins.

water would be unable to diffuse as quick

cell would dehydrate and die

1.     How can a chemical gradient be a source of energy for the cell (think about membrane potential)?

unequal amts of ions on either side of membrane

results in electrical charge that creates an electrochemical gradient

stores energy and creates electricity

Contrast “concentration gradient” to “chemical gradient.”

concentration-concentration of a particular type of molecule

chemical-concentration and inconsistency of ions