CELLS STRUCTURE : CYTOSOL, MEMBRANES

PROTEINS LIKE WATER, HMS YEAR 1

what is cytosol made of ?

concentrated aqueoous gel

function of plasma membrane

define boundaries, provide structure, protects the cell, transport

different components of cell plasma membrane

lipids, proteins, glycolipids, glycoproteins

name the main lipids in the bilayer and their property

phospholipids, cholesterol, glycolipids, —> has AMPHIPATHIC property

describe the self sealing lipid bilayer

• hydrophobic tails fold to form balls so not exposed to water

• bilayer (ball) w/ space in middle

what are the different movement of lipids in the bilayer?

flip flop = switch to different bilayer

rotation = rotate in same position

lateral = exchange w neighbour

name the factors that afect the fluidity of the membrane

double bonds = kink > more fluid at low temp

temp = low reduce fludity

cholesterol = low temp increase fluidity

what are the properties of cholesterol

polar head and non polar tail

change permeability and fluidity of membrane

improve membrane stability

what are the 2 diff types of proteins in membrane and describe their features

integral membrane protein = penetrate both membrane through lipid bilayer

peripheral = penetrate only one side of membrane

describe structure and function of integral membrane

multiple alpha helixes which has gap in middle

allow water soluble mol to cross membrane

name some function of membrane proteins

transporters and channels

anchors

receptors

enzymes

explain how the plasma membrane is reinforced

strengthened by cell cortex which has mesh like structure

cell cortex attached to membrane via transmembrane proteins in inner layer

explain how proteins create barriers

proteins move within bilayer so creat especialised areas

diff proteins on specific areas in bilayer > have specific functions in that area > each area has certain proteins zones with specialised fucntion

name the structure and function of carbohydrates

sugar attached to lipids or proteins

attract water molecules

help cell with protection, recognition and mobility

explain the fluid mosaic model

LIPID RAFTS > lipids cluster together on outer plasma membrane

tightly packed in rafts and influence fluididty

water mol pass through

what is the heterogenity of membranes ?

diff types of phospholipids only stay on one membrane which creates specialised sections and barriers

describe the structure and function of lysosomes

membrane enclosed organelle which contain digestive enzymes

remove damaged organelles and sent it back to be recycled

destroy viruses for cell