Plasma Membrane

Question 1

when was detailed structure of plasma membrane studied

Answer 1

only after the invention of electron microscope in 1950s

Question 2

lipids are arranged in the plasma membrane in such a way that ____________ and ___________ heads towards the outside and ________ and ________ towards the inside
why

Answer 2

hydrophilic and polar
hydrophobic and nonpolar
so that the hydrophobic tail is protected from aqueous environment

Question 3

in human beings, the membrane of erythrocyte has approx. _______ protein and ______ lipids

Answer 3

52 %
40%

Question 4

depending on ___________, membrane proteins can be classified as _______ or __________

Answer 4

ease of extraction
integral
peripheral

Question 5

location of peripheral proteins in plasma membrane

Answer 5

lie on the surface

Question 6

location of integral proteins in plasma membrane

Answer 6

partially or totally buried in the membrane

Question 7

integral proteins which run through the bilayer are known as

Answer 7

tunnel proteins
trans membrane proteins

Question 8

can tunnel proteins be removed easily

Answer 8

no

Question 9

how can tunnel proteins be removed

Answer 9

crude methods such as treatment with detergents

Question 10

the plasma membrane has been described as

Answer 10

proteins icebergs floating in sea of phospholipids

Question 11

improved model of structure of plasma membrane was proposed by

Answer 11

Singer and Nicolson in 1972

Question 12

Singer and Nicolson’s model of plasma membrane was known as

Answer 12

fluid mosaic model

Question 13

what nature of lipids allows lateral movement of proteins in the bilayer

Answer 13

quasi-fluid nature of lipids

Question 14

fluid nature of membrane is important from the point of view of

Answer 14

cell growth
formation of intercellular junctions
secretion
endocytosis
cell division

Question 15

passage of substanced across cell membranes occurs by methods like

Answer 15

active transport
passive transport

Question 16

what is passive transport

Answer 16

many molecules ca move across the membrane without any requirement of energy

Question 17

_________ may move across the membrane by simple diffusion along the concentration gradient

Answer 17

neutral solutes

Question 18

what is osmosis

Answer 18

movement of water across the plasma membrane from higher to lower concentration through simple diffusion

Question 19

what is active transport

Answer 19

uphill movement where particles move against their concentration gradient

Question 20

energy for active transport if obtained from

Answer 20

ATP

Question 21

example of active transport

Answer 21

sodium or potassium pump in animal cells