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chapter 5 Hagar Farag sec.L53 202104799 - Coggle Diagram
chapter 5 Hagar Farag sec.L53 202104799
membrane structure
proteins
integral membrane proteins
lipid-anchored proteins
transmembrane proteins
not all integral protein can move
proteins may bound to components of the cytoskeleton
proteins may bound to molecules outside the cell
peripheral membrane proteins
carbohydrates
by glycosylation
carbohydrates to protein (glycoprotein)
in golgi
carbohydrates to lipid (glycolipid)
in ER
play role in cell surface recognition
protect protein from damage
phospholipid bilayer
amphipathic molecules
The two bilayers asymmertical
synthesize in the cytosol and endomembrane system
Fluidity of membrane
because of lipids and proteins can move within the membrane
semifluid
flip-flop move
requires ATP
factors affecting fluidity
length of fatty acyl tails
presence of double bonds
presence of cholestrol
transport methods
lipids
transported via vesicles
ER-> mitochondria
proteins
ER-> other cell membranes
transported via vesicles
two catagories :
transporters
sugars
amino acids
nucleotides
three types:
symporter
antiporter
uniporter
channels
lipids
selectively permeable
active transport
requires energy
two types :
secondary active transport
primary active transport
against gradient
passive transport
no input energy
two types :
passive diffusion
facilitated diffusion
rate depends on concentration and chemistry solutes
cell gradients
transmembrane gradient
ion electrochemical gradient
tonicity
isotonic
equal water and solute concentration
hypotonic
solute concentration is lower
hypertonic
solute concentration is higher
osmosis
water diffuses
osmotic pressure
tendency for water to move into cell
in animal cells
osmotic lysis
crenation
in plant cells
plasmolysis
crenation
cell wall prevents changes in size
freshwater protists
contractile vacuoles
transport large molecules
endocytosis
pinocytosis
phagocytosis
receptor
exocytosis
vesicles -> extracellular medium