Membrane Structure

Question 1

Function of plasma membrane

Answer 1

1. Encloses the cell
2. Define its boundaries
3. Maintains essential differences between cytosol and extra ellipse environment.
4. Contains proteins that acts as a sensors of external signals.

Question 2

Used to synthesize ATP, to drive transmembrane movement of selected salutes, to product electrical signals

Answer 2

Ion gradients

Question 3

Thickness of cell membrane

Answer 3

5 nm

Question 4

Dissolve readily in water

Answer 4

Hydrophilic molecules

Question 5

Insoluble in water

Answer 5

Hydrophobic molecules

Question 6

Two ways of how lipid molecules aggregate

Answer 6

1. Spherical micelles

2. Bilayers

Question 7

Bonds that produce kinks

Answer 7

Cis double bonds

Question 8

Composition of lipid bilayer

Answer 8

1. Phospholipids
2. Cholesterol
3. Glycolipids

Question 9

Major phospholipids in plasma membrane of mammalian cell

Answer 9

Phosphatidylcholine
Phosphatidylethanolamine
Phosphatidylserine
Sphingomyeline

Question 10

polypeptide that only crosses once

Answer 10

Single pass membrane proteins

Question 11

The polypeptide chain crosses multiple times

Answer 11

Multi-pass transmembrane proteins

Question 12

Polysaccharide chains of integral membrane

Answer 12

Proteoglycan

Question 13

Carbohydrate rich zone on the cell surface. Cell coat

Answer 13

Glycocalyx

Question 14

Have long attracted fatty hydrocarbon chains, holds adjacent molecules together transiently in small microdomains

Answer 14

Sphingolipid

Question 15

Transient phase separations in the fluid lipid bilayer where sphingolipids become concentrated

Answer 15

Microdomains

Question 16

Serves as a signal to induce neighboring cells to phagocytosis the death cell and digest it

Answer 16

Phosphatidylserine

Question 17

Functions of glycolipids

Answer 17

1. Helps protect the membrane from harsh environments

2. Function in cell recognition process

Question 18

Carbohydrate binding proteins

Answer 18

Lectins

Question 19

Rotate to an axis perpendicular to the plane of the bilayer

Answer 19

Rotational diffusion

Question 20

Consists of long polysaccharide chains linked covalently to a protein core, found mainly outside the cells

Answer 20

Proteoglycans