Test Two Membrane Transport Flashcards
what are the two types of membrane transport proteins
carrier and channel proteins
function of carrier proteins
move small molecules through membrane with active transport
channel proteins are what type of channels
hydrophilic pores and ion channels
what are the ions in the cell
Na+, K+, Ca2+, Cl-, and H+
the concentration of Na+ is greater where
outside of the cell
the concentration of K+ is greater where
inside the cell
channel proteins select solutes based on
size and electric charge
carrier proteins select permeability based on
specific fit
impermeability of lipid bilayers prevent what type of molecules from passing
hydrophilic
can ions and charged molecules pass through the bilayer
no
small non polar passing through bilayer is fast or slow
fast
uncharged polar molecules passing through bilayer is fast or slow
slow
channel proteins fast or slow
fast
carrier proteins fast or slow
slow
what was the first evidence of specific transport occuring
mutation in cystinurea (bacteria)
transport direction depends on
molecule concentration
describe passive transport
high to low concentration, no energy source
describe active transport
low to high concentration, uses energy
what are the types of passive transport
simple diffusion, channel, and carrier
what are the types of active transport
carrier
carrier proteins transport what type of molecules
ions and hydrophilic
simple diffusion allows what type of molecules to pass
hydrophobic molecules
what is an example of passive transport
glucose transporter, moves from high to low concentration
transport of charged molecules is dependent on
membrane potential
what is membrane potential
difference in voltage gradient
what is electrochemical gradient
combined concentration and membrane potential gradients
can concentration gradient and membrane potential gradient work in opposite or same direction from each other
can do both
what are the three types of active transport
coupled transport, ATP driven pumps, light driven pumps
what is coupled transport
uphill transport of one solute and downhill transport of another solute
what is ATP driven pumps
uphill transport of solutes with ATP hydrolysis
what is light driven pumps
uphill transport of solutes with input of light energy
uphill transport of a solute must occur before what of the same solute can occur
downhill transport
stages of sodium and potassium pump
Na+ attaches to the pump, ATPase splits ATP to ADP and the pump is phosphorylated, allowing Na+ to enter, K+ attaches to pump and phosphate group is removed from pump allowing K+ to come in
what are coupled transporters
carrier proteins that use uphill of one solute for downhill of another
what are the types of coupled transporters
symport and antiport
what is symport
both solutes either entering or bother exiting the cell
what antiport
one solute comes in while the other goes out the cell
example of symport in animals
glucose Na+ symport, Na+ brings glucose into a glucose rich cell
what is osmosis
the water flows from high to low concentration
what do animal cells need for osmosis
aquaporins
how do animal cells regulate cellular pH
Na+/H+ exchanger symporter is used and Na+/K+ pump keeps Cl- out.
what can happen to animal cells if pumps stop working during osmosis
increased pressure can cause pump to stop working as well as toxin such as oubain but still have Na+ flowing in and this is what causes bursting
how do plants handle osmosis
plant cell walls are really sturdy and can handle the pressure due to turgor pressure
plants, fungi and bacteria use what type of pump
hydrogen pumps
hydrogen pumps in plants are driven by
light
what is the ion selectivity of ion channels
pore size and shape as well as amino acid charge
are ion channels faster than carrier proteins
yes
ion channels causes what type of changes
cellular
voltage gated channels are controlled by
membrane potential
ligand gated channel is controlled by
binding of a molecule
stress activated channel is controlled by
mechanical forces
what is the membrane potential
the electrical potential difference across the membrane
the electrical potential in the membrane potential is controlled by
the transfer of ions
how to maintain the membrane potential
leak channels, movement of ions, equilibrium
structure of neuron
contains cell body, axon, dendrites and nerve terminal
what are action potentials
signals of neurons
signal speeds of neurons are
100 m/s
how can you boost a signal of neuron
by active signaling mechanism
describe the voltage gated Na+ channel
depolarization of plasma membrane by influx of Na+ into cell, Na+ channels open upon stimulus, as Na+ enter in and the membrane becomes depolarized as moving down opening channels. as depolarization moves down the previous channel becomes inactivated then closes.
why does the previous channel in voltage gated Na+ channel become inactivated
to ensure travel in one direction
the synaptic cleft is how big
20 nm
explain voltage gated Ca2+ channel
Ca2+ channel become activated when signal reaches the end terminal of the axon. Ca2+ enters the cell and neurotransmitters are released through vesicles into the synaptic cleft
long distances for passage of signal in action potentials need what
a boosting of signal
purpose of synaptic cleft
to ensure that the signal travels in only one direction and does not reverse
where do neurotransmitters bind when crossing synaptic cleft
bind to cell receptors
when neurotransmitters bind to cell receptor what occurs
chemical signal is converted to electrical signal
examples of excitatory neurotransmitters
acetylcholine and glutamate
function of acetylcholine excitatory neurotransmitter
opens Na+ channels
function of glutamate excitatory neurotransmitter
opens Ca2+ channel
example of inhibitory neurotransmitter
GABA and glycine
function of GABA and glycine inhibitory neurotransmitter
affects Cl-
function of excitatory neurotransmitter
action potential being continued
function of myelin
protects neurons and creates better action potential and ensures signal will go where it needs to
what cells are present in myelin
schwann cells and oligodendrocytes
what cells form myelin
glial cells
what diseases affect myelin sheaths
multiple sclerosis and SIDS
