2.2

Question 1

The Fluid Mosiac Model

4

Answer 1

• States that membrane’s aren’t rigid with molecules locked in place
• Membrane contains phospholipid bilayer, with prteins embedded as a mosaic
• Membrane’s are fluid

membrane “fluid”

Proteins “mosaic”

Question 2

IMAGE

Glycolipid

Glycoprotein

3

Answer 2

Glycolipid:
Membrane Lipid attached to a carbohydrate group

Glycoprotein:
Membrane protein attached to a carbohydrate

Involved in cell-cell recognition and interactions

Question 3

Role of Phospholipids

IMAGE

3

Answer 3

2 Fatty acid tail
(Hydrophobic, non-polar)

Phosphate group, glycerol, polar alcohol

When in aquarius solution, forms a bilayer

Question 4

Membrane Fluidity

Answer 4

Fluidity is dependant on:

1. Composition of lipid molecule (saturated or unsaturated fats)
2. Temperature

Sterol (found in Animals and not plants or prokarotes, also commonly cholesterol) Acts as membrane stabilizers

High temp. = holds the membrane together

Low temp = prevent membrane form becoming too rigid

Question 5

Different roles of membrane proteins

1. Transport

Answer 5

• Hydrophobic protein channels allows to move in and out of cell

Question 6

2. enzymatic activity

Answer 6

• Some membrane routine are enzymes and preform specilized functions such as respiration or photosynthesis

Question 7

3. Triggering signals

Answer 7

• some proteins ca bind to specific chemicals such as hormones, causing changes in the cell

Question 8

4. Attachment and recognition

Answer 8

• Exposed to both internal and external environment
• Involved in cell-cell recognition
• attachment points for cytoskeleton
• Could trigger response

Question 9

Membrane Proteins

Answer 9

Intergral proteins:

• embedded in phospholipid bilayer
• Mostly transport proteins

Peripheral proteins:
- On the surface of phospholipid bilayer
- Held together via hydrogen and ionic bonding
- Most are on cytosol side