Chapter 5- Plasma Membranes

Question 1

What is a plasma membrane made up of?

Answer 1

Phospholipid bilayer

Question 2

Roles of membranes

Answer 2

Partially permeable barriers between the cell and its environment
Sites of chemical reactions
Sites of cell communication

Question 3

Role of a glycoplipid

Answer 3

Acts as recognition site

Question 4

Role of a glycoproteins

Answer 4

Branching carbohydrate portion of a protein which acts as a recognition site for chemicals

Question 5

Role of cholesterol

Answer 5

Used for stability and flexibility

Question 6

How temperature affects membranes

Answer 6

When temperature is increased the phospholipids will have more kinetic energy and will move more. This makes a membrane more fluid and it will begin to lose its structure. If temperature continues to increase the cell will eventually break down completely

Question 7

How does alcohol affect membranes

Answer 7

Breaks them down

Question 8

Define diffusion

Answer 8

Diffusion is the net,or overall, movement of particles from a region of higher concentration to a region of lower concentration

Question 9

Factors affecting rate of diffusion

Answer 9

Temperature

Concentration

Question 10

ATP process

Answer 10

The molecule or in binds to receptor
On the inside of the cell ATP binds to the carrier protein and is hydrolysed to ADP and phosphate
Binding of the phosphate molecule to the carrier protein causes the protein to change shape
The molecule or ion is released to the inside of the cell
The phosphate molecule is realeased from carrier protein and forms ATP

Question 11

Osmosis in a plant cell

Answer 11

Water potential higher outside of solution , means enters cel and becomes more turgid
Water potential same , water enters and leaves , at equal rates
Water potential lower outside of solution , leaves cell , contents shrink