1.3 Membrane Proteins

Question 1

Describe the fluid mosaic model.

Answer 1

There is a phospholipid bilayer, with hydrophilic heads exposed and hydrophobic tails that do not interact with water. The membrane also contains peripheral and integral proteins.

Question 2

Discuss the chemical nature of peripheral and integral proteins.

Answer 2

Integral proteins have hydrophobic r-groups, where as peripheral proteins have hydrophilic r-groups and are loosely bound to the membrane surface.

Question 3

Name the two molecules that can cross the membrane by simple diffusion.

Answer 3

Carbon dioxide and oxygen.

Question 4

Describe the process of facilitated diffusion

Answer 4

Passive transport of substances using carrier proteins that transports molecules down the concentration gradient.

Question 5

Why do different cell types have different channel and transporter proteins?

Answer 5

To carry out specialized functions.

Question 6

Discuss the structure of aquaporin.

Answer 6

Composed of multiple subunits, with 7 transmembrane spanning channels.

Question 7

Explain the difference between a voltage gated channel and a ligand gated channel.

Answer 7

A ligand gated channels opens in response to conformational changes because of the binding of ligand where as a voltage gated channel opens in response to localized changes in charge.

Question 8

What type of membrane protein facilitate active transport.

Answer 8

Pumps.

Question 9

Discuss the ATP requirements of pump proteins.

Answer 9

They require ATP in order