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What are the primary lipid components of plasma membrane
Glycerol based phospholipids, sphingolipids, cholestrol
What is the role of cisternae?
Protein synthesis and modification. They give space for ribosomes to attach and synthesize proteins
What leaflet are glycerol based phospholipids on
Inner and outer leaflet
What leaflet are sphinglipids on
Outer leaflet
What leaflet are cholestrol on
Embedded within phospolipid bilayer, outer leaflet
What is diff between phosphoglyceride and sphingolipid backbone
Phosphoglycerides use glycerol and sphingolipids use sphingosine
Function of phosphoglycerides
Maintain structure of bilayer, responsible for allowing things to/not to pass through
Function of sphingolipids
Maintain structure of membrane, act as signaling molecules, and help with cellular processes like growth, apoptosis, and differentiation. Make up lipid rafts
How are membrane phospholipids synthesized
Synthesized in cytosolic leaflet of smooth ER by fatty acid building blocks from cytosol or food
How are membrane phospholipids trafficked
Transported via vesicles by proteins that are specific for transport to/from a certain organelle or by lipid exchange proteins
Role of lipid exchange proteins
Move lipids from one membrane to another
How are membranes asymmetric
Membranes have different concentrations of lipids types on outer vs inner leaflets
What lipids types are more common on inner leaflet
Phosphodylynserine and Phosphoethanolamine
What phospholipid types are more common on outer leaflet
Phosphodylyncholine and sphingomyelin
Flippase vs. scramblase
Flippase moves lipids form outer leaflet to inner leaflet with the help of ATP whereas scramblase swaps 2 lipids for each other without help of ATP
Why are membranes fluid and why do they need to be fluid?
Membranes are fluid because cell conditions are constantly changing, you need to be able to move lipids and proteins around to meet cell needs at the moment.
What increases or decreases membrane fluidity
Cholestrol - stabilizes membrane by making it less fluid during high temp and more fluid during low temp
Length of fatty acid tails - shorter tails interact less. andmake membrane more fluid
Double bonds - absence of double bonds makes membrane less fluid because it can pack more tightly together
Peripheral vs. integral membrane proteins
Noncovalent vs. covalent attachment. Peripheral can also be attached to phospholipid head
Types of integral membrane proteins
Transmembrane - span membrane
Lipid anchored- covalently attached to lipid that is attached to bilayer
Simple diffusion
Move with gradient from high to low concentration directly through membrane, no ATP
Facilitated diffusion
Move with gradient from high to low concentration with the help of a channel, no ATP
Example of facillitated diffusion
Glucose transporter
Active transport
Move against concentration gradient from low to high concentration, requires ATP
Describe the movement of water via osmosis
Water will move from low concentration of water to high concentration of water until the amount of solute to amount of water distribution matches
Hypotonic, hyperotnic, isotonic
water moves into cell, cell bulges
water moves out of cell, cell shrivels
concentration is equal on both sides of cell
Channel vs. transporter proteins
Channel proteins open/close, allowing molecules to pass without binding whereas transporter proteins enact conformational change due to substrate binding
Uniporters vs. symporters vs. antiporters
A single solute molecule moves in one direction
2 solutes move in same direction
2 solutes move in opposite directions
Why are ion channels highly specific
Ion channels have charged amino acid residues that only allow certain molecules to pass through. They open and close as needed and move with the concentration gradient
Primary active transport vs secondary active transport
Primary active transport uses ATP to move things against the concentration gradient, like the sodium potassium pump. Secondary active transport uses the electrochemical gradient created by by primary active transport to move things against concentration gradient