Chapter 5: Membrane Structure And Transport Flashcards
what is the plasma membrane structure?
phospholipid bilayer
cholesterol
proteins
what are the two proteins in the plasma membrane?
integral and peripheral
what is integral membrane protein?
protein all the way through the membrane
what is the peripheral membrane protein?
proteins attached on the outside of the membrane. they are attached by bonds that are easily broken
cholesterol is a steroid which is a type of
Lipid
what can peripheral membrane proteins attached to?
outside or cytoplasm and use h bonds or ionic bonds
cholesterol is inserted into the membrane so the 4 rings are next to the
fatty acid chains
what does cholesterol give to the plasma membrane?
mechanical strength and maintains fluid because it has to be stiff enough to be a barrier but loose enough to move
what are the 3 types of PM proteins?
peripheral
integrated
glycoproteins
embedded in the phospholipid bilayer of pm
integral
how can you remove integral membrane proteins?
destroy the membrane
what are glycoproteins and location?
integral membrane proteins with sugars covalently attached to
part of protein with the sugar is located in the surface of the pm
will glycoproteins ever be found in the cytoplasm surface?
no
what proteins are used to mark cells?
glycoprotein
what are the functions of pm?
compartmentation- different jobs done in the cell. you put all enzymes need in that specific membrane
communication- with other cells and environment
transport
what separates the living cell from the external environment?
Pm
what is differently permeable?
membranes- only certain molecules can pass through it
why does the lipid bilayer make a good barrier?
it’s hydrophobic
most chemicals in cell are hydrophilic so the can’t dissolve in hydrophobic areas
most salts and biological are
hydrophilic
what can’t hydrophilic molecules pass through?
hydrophobic layer
what can’t sugars pass through by themselves?
lipid bilayer
what substances can pass through a membrane without a transport protein?
substances that are pliable in the hydrophobic part of the lipid bilayer
what molecules can pass through the pm?
water
small, uncharged (O2, CO2)
hydrophobic molecules (steroids)
what molecules can’t pass through the pm?
charged ions
charged molecules
Large macromolecules
polar organic molecules (glucose)
what is simple diffusion?
gradient
energy
substance moves from a higher concentration to a lower concentration
movement is down the gradient concentration
no energy is needed
what happens after diffusion?
equilibrium
what is osmosis?
energy
the diffusion of water
moves water from a high concentration to a lower concentration
no energy is needed
what is concentration?
amount of solute in a certain volume
% solution= # g solute in final volume of 100 ml
a _ solute concentration = _ water concentration
high
Low
what is a concentrated solution?
high solute/ low water
what is a dilute solution?
lower solute/ higher water
what is hypertonic?
too much substance
too little water
what does high salt cause the cell to do?
shrivel up
what is hypotonic?
too little substance
too much water
what is isotonic?
solute in and out are equal
in what cells do cells burst?
animal
not plants
is dialysis tubing semipermeable?
yes so small molecules like water, salt and ions can pass through. it has little pores
what can’t pass through dialysis tubing?
large organic molecules
in simple diffusion which way will the solute move?
down it’s concentration gradient
high to low
where does the solute pass through in simple diffusion?
lipid part of membrane - no transport protein needed
only substances that are soluble in the lipid bilayer can pass through the membrane by
simple diffusion
ex: 02, C02, steroids
what is facilitated diffusion?
gradient
energy
solute moves from a high concentration to a low concentration
down its gradient
no energy needed
what solutes use facilitated diffusion?
non soluble solutes in lipid part of membrane
ions, polar molecules, sugars, macromolecules
what does facilitated diffusion require because it can’t pass directly through membrane?
transport protein
in facilitated diffusion, chemicals must be transported in which direction?
the same- down the gradient
what are the types of passive transport?
osmosis, simple and facilitated diffusion
all passive transport move _ its concentration gradient and _ need an energy input
down
doesnt
what is active transport?
gradient
energy
solute moves from a low concentration to a high concentration
moves against gradient
energy required since it is against (atp, gtp, ion gradient, light, other high energy compounds
does active transport need a transport protein?
yes- it is not solvable in lipid bilayer (ions, polar molecules, organic molecules)
true or false: some molecules will use both facilitated diffusion and active transport?
yes- depending on which way it is moving
types of active transport
direct and indirect
what is direct active transport?
primary active transport
solute moves from a low to a high concentration
type of energy is usually atp, other high molecules, light
what is indirect active transport?
secondary active transport
two part system: protein one sets up an ion gradient across the membrane (H+ -ATPase or Na/K- ATPase)
protein two uses ion gradient as a source of energy to transport substance across the membrane and against the gradient
in indirect active transport, ion moves from high to low releasing
energy
what are the types of transport proteins?
uniport- one chemical transported
symport- two chemicals transported at the same time in the same direction
antiport- two chemicals transported at the same time in opposite directions
(either facilitated or active)
what is exocytosis?
moves substance out of cell
substance is packed into a vesicle which fuses with pm and the contents of vesicle are released outside of the cell
energy transport for exocytosis?
gtp
what are examples of exocytosis?
release of hormones and enzyme neurotransmitters
what is endocytosis?
brings select substances into cell
substances bind to receptor protein, in outside of pm which the pm invaginates and vesicle forms. then the vesicle is sent to lysosome and substance is broken down for subunits to be used k. Cell
energy for endocytosis?
gtp
