module 2-plasma membranes Flashcards
membranes
formed from phospholipid bilayer.
head=hydrphillic
tail=hydrophobic core
inside=aqeuous solution
fluid moasic model
phospholpids are free to move, membrane is flexiable and proteins are scattered as moasics.
channel proteins
allowing passive movement of polar molecules and ions
carrier proteins
help by changing shape of protein.
glycoproteins
sugar chain
receptors for chemical signals
cell adhesion and signalling
glycolipids
lipids with carbohydrate chain
antigens
chloesterol
lipid with hydrophillic head and hydrophobic tail.
add stability, as prevents it becoming solid.
factors affecting membrane
temperature
solvents
how does temp affect membranea?
as more kinetic energy, leading to more fluid losing structure, so more premability, and also denatures enzyme.s
solvents?
Alcohol is toxic, destroys cell, disrupts membrane
diffusion
net movement of particles from a high concentration to a low concnetration.
factors=temp, concentration difference, surface are and thickness
facillated diffusiom
polar atoms=selectively permable
no need of energy
involves carrier proteins.
active transport
low concentration to high
energy and carrrier proteins form bulk transport
bulk transport
endocytosis, and exocytosis
endocytosis
materials to cell
membrane bend inwards, and enfolds material, until membrane fuses=forms vesicle which pinches to membrane
