Ch. 5 membrane dynamics

Question 1

Define simple diffusion.

Answer 1

Diffusion directly across the phospholipid bilayer, down a concentration gradient, by permeating solutes.

Question 2

Define facilitated diffusion.

Answer 2

Passive transport of larger or polar molecules down a concentration gradient, across the membrane with the help of membrane proteins

Question 3

Define channel protein and both types of channel proteins.

Answer 3

Channel proteins create water-filled passageways linking ECF and ICF

Leaky channels remain open

Gated channels are closed and can be opened by chemical, electrical or mechanical stimuli

Question 4

What are proteins embedded in the membrane called?

Answer 4

Integral or Membrane Proteins

Question 5

Carrier proteins that move only one kind of molecule

Answer 5

Uniport Carrier

Question 6

Carrier proteins that move more than one kind of molecule at a time

Answer 6

Cotransporter

Question 7

Carrier proteins that move two different molecules in the same direction

Answer 7

Symport Carriers

Question 8

Carrier proteins that move proteins in opposite directions

Answer 8

Antiport Carriers

Question 9

Define resting membrane potential.

Answer 9

An electrical gradient between the extra- and intra- cellular fluid.

Question 10

What is a tranpsort maximum?

Answer 10

the maximum amount of absorbable molecules by a carrier protein

Question 11

What is the extracellular glycoprotein layer that sits just outside the phospholipid membrane of some cells?

Answer 11

Glycocalyx

Question 12

What are the 5 functions of the cell membrane?

Answer 12

• shape
• protection
• transport of molecules into/out of cell
• cell adhesion
• indentification