Week 3 Cell Membrane

Question 1

Give 2 other names for the cell membrane?

Answer 1

Plasmalemma or plasma membrane.

Question 2

List the 4 functions of the cell membrane?

Answer 2

Physical isolation, regulates exchange with environment, monitors the environment, & structural support.

Question 3

What are the 3 main components of the cell membrane?

Answer 3

Lipids, proteins & carbohydrates.

Question 4

What does the phospholipid bilayer consist of?

Answer 4

A double layer of phospholipid molecules: Hydrophilic phosphate heads & hydrophobic fatty-acid tails.

Question 5

List the 6 functions of membrane proteins?

Answer 5

Anchoring proteins, recognition proteins, enzymes, receptor proteins, carrier proteins & channels.

Question 6

What are the functions of membrane carbohydrates?

Answer 6

Lubrication & protection, anchoring & locomotion, specificity in binding & recognition.

Question 7

What are the 3 categories of cell membrane transport?

Answer 7

Diffusion (passive), carrier-mediated (passive or active), & vesicular (active).

Question 8

What factors affect diffusion rates?

Answer 8

Distance, molecue size, temperature, gradient size, & electrical forces.

Question 9

What are the 2 types of diffusion?

Answer 9

Simple & channel-mediated.

Question 10

What factors affect channel-mediated diffusion?

Answer 10

Size, charge & interaction with the channel.

Question 11

What is osmosis?

Answer 11

The diffusion of water across the cell membrane.

Question 12

What is osmotic pressure?

Answer 12

The force of a concentration gradient of water. It equals the force (hydrostatic pressure) needed to block the process of osmosis.

Question 13

What is another name for vesicular transport?

Answer 13

Bulk transport.

Question 14

What are the 3 types of carrier-mediated transport?

Answer 14

Facilitated diffusion (passive), Primary active transport & Secondary active transport.

Question 15

What are the characteristcs of carrier-mediated transport?

Answer 15

Specificity, saturation limits & regulation.

Question 16

How does facilitaed diffusion work?

Answer 16

Carrier proteins transport molecules too large to fit through cannel protiens (e.g. glucose). The molecule binds to a receptor site on the carrier protein, the protein changes shape & the molecule can pass through. The recptor is specific to certain molecules.

Question 17

Primary active transport moves substrates against a concentration gradient & therefore requires energy in the form of ATP. True or false?

Answer 17

True e.g. sodium/potassium pump

Question 18

What is countertransport?

Answer 18

the active transport of one substrate moving into the cell while another moves out.

Question 19

What is another name for countertransport?

Answer 19

Antiporters.

Question 20

What is another name for cotransport?

Answer 20

Symporters.

Question 21

What is cotransport?

Answer 21

A primary active transport of 2 substances in the same direction at the same time.

Question 22

What are the 2 types of vesicular transport?

Answer 22

Endocytosis & exocytosis.

Question 23

What are the 3 types of endocytosis?

Answer 23

Receptor-mediated, pinocytosis & phagocytosis.

Question 24

What is pinocytosis?

Answer 24

“Cell drinking”. The taking in of water by a cell.

Question 25

What is the difference between integral & peripheral protiens?

Answer 25

Integral sit within the cell memebrane & peripheral are on the inner or outer surface of the cell membrane.