Lecture 2 Cell Membrane

Question 1

Roles of cell membrane

Answer 1

1. Selective barrier
2. Transport
3. Communication & cell signalling
4. Cell adhesion

Question 2

Composition of cell membrane

Answer 2

• Lipids 40%
• proteins 50%
• Glucids 10%

Question 3

Lipids
Phospholipids

Answer 3

1. The barrier function of the cell membrane.
2. The fluid and dynamic character of the cell membrane necessary for carrying out various cellular activities

Question 4

Lipids
Cholesterol

Answer 4

stability, rigidity

Question 5

Lipids
Glycolipids

Answer 5

Rare, external layer

Question 6

Proteins
Intrinsic

Answer 6

Covalent bonds with lipids in the bilayer

Question 7

Proteins
Extrinsic

Answer 7

Ionic bonds with lipids or integral proteins

Question 8

Proteins

Outside the cell =

Answer 8

Ectoproteins

Question 9

Proteins

Inside the cell =

Answer 9

Endoproteins

Question 10

TRANSPORT OF IONS AND SMALL MOLECULES

Answer 10

1. Diffusion
   • simple diffusion
   • Facilitated Diffusion
2. Active transport
   • Direct active transport
   • indirect active transport

Question 11

TRANSPORT OF MACROMOLECULES AND PARTICLES

Answer 11

Exocytosis = the process by which the macromolecules synthesized in the cell are packed into vesicles, transporters and eliminated into the extracellular environment.

Constitutive exocytosis
- the continuous elimination into the extracellular environment

Regulated exocytosis
- in specialized cells that temporarily store synthesized proteins in secretory vesicles and remove them into the extracellular environment only after a specific stimulus