Lecture 5

Question 1

What are organelle membranes

Answer 1

Create compartments within cells to concentrate molecules

Question 2

What does the plasma membrane do?

Answer 2

Separates cytoplasm from interstitial fluid

Question 3

Phospholipids

Answer 3

Forms selectively permeable barrier and allows small and non polar molecules to pass through

Question 4

Plasma membrane functions

Answer 4

Transport
Communicate
Metabolism 
Structure 
Self identify markers

Question 5

What 2 things does membrane transport require?

Answer 5

Driving force and pathway

Question 6

What is driving force?

Answer 6

1) concentration gradient
- drive molecules down/with concentration gradient
- moves from high to low concentration
- passive process, no added energy
2) ATP
- powers protein pump that drives molecules up against a concentration gradient.
- From low to high.
- energy from atp drives movement

Question 7

What is the pathway in membrane transport

Answer 7

• Determined by 2 things. Molecule size and polarity
• small molecules pass between phospholipids
• larger molecules/monomers require protein transporters

For polar molecules - non polar can pass freely through phospholipids. Polar require protein transport