2.1.5 Biological membranes - Phospholipid bilayer Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Define plasma membrane

A

The cell surface membrane with separates the cell from its external environment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

From what are membranes formed?

A

From a phospholipid bilayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the structure of a phospholipid bilayer?

A

the fatty acid tails are hydrophobic (and non-polar) therefore they face inwards. the phosphate heads are hydrophilic (and polar) therefore they face outwards. this causes the phosphate heads to sandwich the fatty acid tails in the middle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is the phospholipid bilayer perfectly suited as membranes?

A

since the outer surfaces of the hydrophilic phosphate heads can interact with water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is the model known as the fluid mosaic model?

A

The fluid part because the phospholipids can move relative to each other. And mosaic because there are proteins embedded in the bilayer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the features of a cell-surface membrane?

A
  • phospholipids
  • cholesterol
  • intrinsic proteins OR extrinsic proteins
  • glycoproteins
  • glycolipids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Channel proteins -

A
  • embedded in phospholipid bilayer
  • provides a hydrophilic channel which allows the passive movement of polar molecules or ions down a concentration gradient through a membrane.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Carrier proteins -

A
  • embedded in cell-surface membrane
  • permits facilitated diffusion
  • play an important role in transporting substances across the membrane down the concentration gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Glycoproteins -

A
  • made out of proteins
  • intrinsic proteins, embedded in cell surface membrane
  • attached are sugar chains
  • FUNCTION: help cell adhesion and as receptors for chemical signals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Glycolipids -

A
  • made out of lipids
  • similar to glycoproteins
  • they have attached a sugar chain (carbohydrate)
  • they are cell markers or antigens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Extrinsic proteins -

A
  • present on side of the bilayer
  • normally have hydrophilic R-groups on their outer surfaces and interact with the polar heads of the phospholipids or with intrinsic proteins.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Cholesterol -

A
  • lipid that has a hydrophilic end and a hydrophobic end

- FUNCTION: regulate fluidity of membranes and to add stability to membranes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly