B2.1- transport accross membranes Flashcards
simple diffusion depends on
size and phobic/phillic nature of particles
channel proteins do movement
(((concentrzation gradien t)))
down the concentration gradient
active transport needs …. pro
carrier prpteins which ungergo a conformational change
OSMOSSI DEFINITION
the diffusion of water across a selectively permeable membrane from a solution of a lower concentration to a higher concentration.
osmosis diffrences from diffusion
only happens accross membrane
diffusiion OF WATER
concentration of solute is higher in cell than outside, so water moves into cell
(diffrentt in oceans due to more solutes as the salt)
aquaporins structure
are intergral proteins
made of 4 monomeric subunits. which each have a water channel, lined up with phillic side chains
allowing water to go through but not ions.
they are bidirectional
why are channels in aqua porins phillic
phobic layer of lipid lilayer doesnt allow polar through so phillic do
simple difffusion is
the movement of particles DIRECTLY THROUGH BILAYER with no energy
facilitated diffusion is
the movement of solutes down concentration gradient but size/polar natuee affects if they cross membrane
carrier/channel proteins help movement
passive transport
no energy and high to low concentration
(diffusuion is type of passive)
activw transport needs
energy from atp and is low to high
Direct transport
Direct is when energy is released by an exergonic reaction like the breakdown of atp to transport molecules across cell membranes. These are called ATPase pumps.
Indirect transport
Indirect active transport is where the movement of the solute down the concentration gradient drives the movement of the 2nd solute against the concentration gradient.
active transport is used……………………………………………..
s used on the cell membrane with carrier proteins. It helps to take essential nutrients (like the uptake of glucose), is also removes secretory/waste materials from the cell
