2.1.5 Biological membranes

Question 1

describe the mosaic model of cell membrane

Answer 1

a phospholipid bilayer with extrinsic proteins and intrinsic proteins channel

Question 2

function of glycoproteins

Answer 2

allow cells to regconises other cells and form tissues

Question 3

function of channel protein

Answer 3

help molecules that are too larger/ too hydrophilic to cross membrane

Question 4

function unsaturated fatty acids in bilayer

Answer 4

increase fluidity

kinds shape - more stability

Question 5

facilitated diffusion 4

Answer 5

• movement of molecules from high to low conc
• across a semi permeable membrane
• via proteins channels
• no ATP

Question 6

active transport

Answer 6

• movement of substances against their conc gradient
• ATP
• proteins carriers

Question 7

Describe the structure of a plasma membrane.

Answer 7

• phospholipid bilayer containing proteins ;
• head / hydrophilic region, facing outwards
  OR
  tail / hydrophobic region, facing inwards ;
• ref to intrinsic and extrinsic (glyco)proteins /
• glycoproteins / glycolipids, sticking out (of
  bilayer / membrane);
• cholesterol, inside bilayer between phospholipids provide fluidity