Week 2 Part 2: Cell Membrane

Question 1

What is Membranes

Answer 1

asymmetric
viscous and plastic structure
dynamic structure
Thermodynamically stable and metabolically active
noncovalent assemblies

Question 2

Why membranes are asymmetric structure?

Answer 2

In terms of inside-outside asymmetry and regional asymmetry

Question 3

What functions are cell membranes?

Answer 3

1. Permits cell individuality
2. Has selective permeability
3. Important for cell to cell interaction and adhesion
4. Important in transmembrane signaling
5. form specialized compartment for organelle
6. localize enzyme
7. integral elements in excitation-response coupling

Question 4

THE 2 MAJOR BODY
COMPARTMENTS OF CELL MEMBRANE

Answer 4

1. Intracellular Fluid Compartment (ICF)
2. Extracellular Fluid Compartment (ECF)

Question 5

Contains 2/3 of body water,
Provides environment for the cell to
 Synthesize, store and utilize energy
 Repair itself
 Replicate
 Perform special functions

Answer 5

Intracellular Fluid Membrane

Question 6

Contains 1/3 of total body water
distributed between PLASMA and
INTERSTITIAL FLUID compartments
Is a delivery system of nutrients, ions, oxygen and hormones to cells
Removes waste products from the cells

Answer 6

Extracellular Compartment Fluid

Question 7

What are the substances in cell membrane

Answer 7

Na+
K+
Ca2+
Glucose
Protein
Mg2+
Cl-

Question 8

COMPOSITION OF CELL MEMBRANE

Answer 8

I. Lipids
II. Proteins
III. Carbohydrates

Question 9

provides the basic structures of
biological membranes

Answer 9

Lipids

Question 10

perform most of the
membrane’s specific tasks

Answer 10

Proteins

Question 11

Major Membrane Lipids

Answer 11

1. Phospholipids
   1.1. phosphoglycerides - most abundant
   1.2. Sphingomyelin
2. Glycosphingolipids
   2.2. cerebrosides
   2.3 gangliosides
3. Sterols
   3.1 cholesterol

Question 12

What is membrane lipids?

Answer 12

Amphipathic
Forms BILAYERS
Fatty acids may be saturated or saturated

Question 13

Draw the Structure of phospholipids

Answer 13

Polar Head Group
Apolar, hydrocarbon tails

Question 14

Draw the structure of Lipid Bilayer

Answer 14

Aqueous - Hydrophillic
Hydrophobic
Aqueous - Hydrophilic

Question 15

formed by SELF-ASSEMBLY driven by HYDROPHOBIC EFFECT

Answer 15

Lipid bilayers

Question 16

are the more common membrane phospholipid

Answer 16

PHOSPHOGLYCERIDES

Question 17

is prominent in myelin sheath, glycerol is its backbone

Answer 17

SPHINGOMYELIN

Question 18

Sugar-containing lipids built on a backbone of ceramide

Answer 18

GLYCOSPHINGOLIPIDS

Question 19

Most common sterol in membranes  Intercalates among phospholipids in the cell membrane  Is also amphipathic with its hydroxyl group lying at the aqueous surface  “moderator molecule”

Answer 19

CHOLESTEROL/STEROL

Question 20

ROLE OF CHOLESTEROL

Answer 20

Modifies membrane fluidity
At high temperatures (above Tm ), its rigidity increase

At low temperatures (below Tm ), it INCREASES FLUIDITY

Question 21

What is MEMBRANE PROTEINS and it’s function

Answer 21

Different membranes have different protein compositions  Functions of membrane proteins :  Enzymes  Pumps, channels, carriers  Antigens  Receptors  structural proteins