b.2.1 Flashcards
head of bilayer
hydrophillic
prosphate
polar
soluable
tails bilayer
hydrocarbon fatty acid
unpolar
unsoluable
what type of substance can join membranes
cholesterol
permeability of membranes and why
LOW permeability not much can pass
- large cannot pass
- polar cannot pass
- ions cannot pass
inegral proteins
- hydrophobic
- embedded into one or two sides of BI-layer
peripheral
- hydrophillic
- attatched to surface of integrals via hydrocarbon chains
what are proteins used for in bilayer
- transport
- reception
- regognition
recptors in bi-layer
binds things to set of cell reactions
transport in bilayer
movement in or out
immobilized enzymes bi layer
immobilized with active site facing out
adhesive bi layer proteins
attatches to neighbous
regognition proteins
glycoproteins
simple diffusion defention
“net movement, as a result of the random motion of molecules or ions, from a high concentration to a low concentration” - passive down concentration gradient
what effects diffusiion rates
- concentrations
- temp
- surface areas
net movement
the movement of high to low even though the random movement still means they are going both ways
two examples of simple diffusion
- oxygen from capilaries into cells for respiration
- co2 from cells to capiliairies
osmosis defenition
“the diffusion of water molecules from a dilute solution to a high solute solution across a particaaplly permanent membrane”- passive down concentration ggradient
high water concentration - low water concentration can otherwise be known as
low solute - high solute
what are aquaporins
trans membrane integral porins that dont reequre engery but allow water though
what does facilitated diffusion allow through
- large moleccules
- polar
- ions
two types of facilitators
- channel
- carrier
they are very specific only allow specifc stuff
facilitated diffusion defenition
passive movement of molecules from lower to higher concentration usuing integral protei
- passive
- down concentration gradient
active transport
“the movement of molecules and ions acros a cell membrane from a lower concentration gradinet to a higher concentration gradient using engery from respiration
- active
- uses engery
- up gradient
facts on active transport
- pumps
- protein changes shape
- uses atp
- only works in one direction but reverse doesnt require energy
what is selective permeability
being selcetive on the molecules that can pass through the layer
- facilicated diffusion and active transport
simple diffusion is how permeable
partially, it allows small and none polar molecules to pass but not large polar molecules
glycoproteins
proteins in membrane layer has a carbohydrate chain atttacthed
glycolipids
lipids in the bilayer with a carbohydrate attatched
what do carbohydrate chains allow for
signalling receports
recepotors for endocytosis
celll adhesion and stablization
cell adhesion
carb chains form a layer called glycolaxes wich binds to adjacent cells
cell recognition
carb chains are used to identiy pathogens
fluid mosaic model
- 1972 singer and nicolson
- explains how proteins and lipids are subunits that can move freely yet cannot flip
- includes: phospholipids, colestrol, glycoproteins and lipids, peripheral proteins
intgral proteins
channels, carries and pumps
peripheral proteins
just on surface of membrane
gygoproetins
have a carb
cholesterol
the OH parts sits with phophate head and the rest is in the layer
