Unit 2 cell membrane

Question 1

What is the cell membrane?

Answer 1

semi-permeable phospholipid bilayer
material:
-phospholipids
-polar head (hydrophilic)(reactant side)
-non-polar tail (hydrophobic)
-amphillic
-2 layers

Function:
1. structure
2. decides what goes in and out
3. serves as a id to identify cell
-in: small + no charge
-out: waste

Question 2

Describe the Fluid mosaic model used to model the cell membrane

Answer 2

Fluid mosaic model= movement of many parts
-cell membrane is always moving and is made of many parts
-all parts work together and have no pattern

Question 3

What 3 factors affect the fluidity of the cell membrane
1.
2.
3.
4.

Answer 3

1. Temperature:
-hot = fluid
-cold= stiff

2. Double bonds carbon :
=bends = fluid

3. single bonds carbon:
=straight = stiff

4.cholesterol
-more = stiff

Question 4

where can proteins be found around the cell membrane?
1. 2.

Answer 4

1.** peripheral proteins:**
-bind to polar head of cell membrane or other proteins
-outside membrane
Ex. enzymes

2. integral proteins/transportation proteins
   -in the membrane (span the entire thing)
   -amphillic
   Ex. channel proteins

Question 5

Describe the 4 types of proteins around the cell membrane?
1.
2.
3.
4.

Answer 5

1. transport proteins:
   -integral proteins
   -deliver things that membrane won’t let through
   -active and passive transport
2. enzymes
   -peripheral proteins
3. signalling/triggering
   -peripheral
   -changes the shape of proteins
4. attachment and recognition proteins
   -peripheral
   -binds to membrane so other things can bind to it
   -communication

Question 6

Why does carbohydrates bind to the membrane?

1. Glycolipids:
2. Glycoproteins:

Answer 6

-recepter cells
-identifiers

1. Glycolipids:
   carbohydrates on membrane
2. Glycoproteins:
   carbohydrates on proteins
   -peripheral or integral