5.0 Flashcards
(15 cards)
What is compartmentalisation
The formation of separate, membrane bound areas
What is the structure of a membrane
A phospholipid bi layer with the hydrophobic tails facing inwards and hydrophilic tails facing towards the surroundings due to their aqueous environments
What are the components of a cell membrane
Cholesterol-stability
Glycoprotein-recognition site for chemicals
Glycolipid-recognition site
Carrier proteins-facilitated diffusion
Channel proteins-diffusion
What are intrinsic proteins
Proteins embedded trough layers of a membrane such as channel or carrier proteins
Factors affecting membrane structure
Temperature-more kinetic energy=more fluid structure=lower structural integrity = more permeable
Solvents ( non-polar ) - disrupts membrane barrier and causing lysis of most cells
What is the diffusion
The passive, net movement of particles from a higher to a lower concentration
How does diffusion occur across membranes
Only if the membrane is permeable in the particles
Non-polar molecules diffuse freely
Ions are repelled by the hydrophobic interior but polar molecules can diffuse through at a slow rate
(Partially permeable)
What is facilitated diffusion
A method with which polar molecules can cross a phospholipid bi-layer
Use of carrier proteins
Dependant on temp, conc grad, S.A. And carrier protein n.o.
What is bulk transport
A form of active transport which involves the movement of larger molecules in and out of a cell
(Endo/exo cytosis_
Endo: phagocytosis (solids) + pinocytosis (fluids)
Invaginates + enfolds until a vesicle forms
Exo: vesicle fuses with c.s.m then release vesicle contents
Osmosis definition
The net movement of water molecules from a higher to a lower water potential
What happens to an animal cell in an excess of water
Cytolysis
What is the name of the pressure against the cell wall in plant cells
Turgor
