Eukaryotic Cell - Cell Membrane (2)

Question 1

who proposed the, improved model of the Structure of Cell membrane

Answer 1

Singer and Nicolson (1972) , widely accepted as fluid mosaic model

Question 2

What is the nature of the lipid

Answer 2

its has Quasi - fluid nature

Question 3

how does it help in movement?

Answer 3

it helps in lateral movement of proteins throughout the overall bilayer

Question 4

what is the ability to move within the membrane known as?

Answer 4

Fluidity

Question 5

How is the fluid nature of membrane important?

Answer 5

its important from point of view of functions like
- cell growth
- formation of intercellular junctions
- secretion
- endocytosis
- cell division

Question 6

functions of Plasma membrane

Answer 6

• one of the most important functions of plasma membrane, is transport of molecules across it.
• The membrane is selectively permeable to SOME molecules present on either side of it.

Question 7

Describe the transport of molecules across the membrane

Answer 7

• many molecules can move briefly across the membrane without any requirement of energy and is called passive transport

Question 8

How do they move across the membrane without the requirement of energy

Answer 8

-Neutral solutes may move across membrane by the process of simple diffusion along the concentration gradient ( from higher to lower)

-water may also across this membrane from higher to lower by the process of osmosis

Question 9

What about the polar molecules that cannot travel through non polar lipid bilayer?

Answer 9

-they require carrier proteins of membrane to facitilate their transport across membrane

• A few ions or molecules move against concentration gradient from lower to higher concentration this is an energy dependent process in which ATP is utilised it is known as active protein.