This pump is an example of secondary active transport; driven by an ion gradient NO ATP is directly required.
This differs from _____ active transport that is driven by ATP hydrolysis (eg Na + or K+ pump)
this is a _____ pump
Primary active transport (require ATP hydrolysis)
ion gradients are established by _____ <-- ATP hydrolysis
there are _ major classes of ATP-driven pumps
- all _ major classes are found in ____prokaryotic/eukaryotic cells
both cell types
A __ type ion pump phosphorylates themselves during the pumping cycle
this kind of pump is found in the __ ___ of bacteria and inner membrane of mitochondria as well as the ____ membrane of chloroplasts. This type of pump is also called ATP synthases. This kind of pump is called a ___ pump.
plasma membrane (bacteria)
Thylakoid membrane (chloroplasts)
V-type ATPases (V from vacuole) are structurally related to ____ pumps except the v-pump works in the _____ direction
___ transporters are they largest family of membrane transport proteins. Unlike the other three classes of pumps, these transporters also pump ____ across the membrane.
one important example of a pump is a P-type pump called the ____
Na+-K+ pump and is an antiporter
Binding of Na+ triggers ________________ while binding of K+ triggers ________
The Na+ - K+ pump helps the ___ ___ ____ in animal cells and regulates ____ ____ (affects movements water via osmosis through lipid bilayer and aquaporins)
resting membrane potential
In a ____ environment the cell crenates (shrinks). In a ___ environment the cell swells and will even lyse. A normal shaped cell is in a ____ environment.
Ion channels have an _____ pore that permits _____ of ions. They have 2 important characteristics.
1) ion selectivity (narrowest part of chanel called selectivity filter)
2) most ion channels are gated (usually closed will open briefly in response to stimulus)
* if the stimulation is prolonged, most channels go into a closed inactivated stated
there are >___ types of ion channels
an individual neuron can have >__ types of ion channels
the most common channels are _____. Some are permanently open and they are called ___ _____
They play an important role in the establishment of the ___ ___
K+ leak channels
membrane potential exists when there is an ___ distribution
of + and - ions on both sides of a membrane . When such distribution occurs the membrane becomes ____
A membrane potential exists due to these 3 things?
1) action of Na+- K+ pump
2) electrochemical gradients for K+, Na+, Cl- ect
3) differential permeability of the plasma membrane
neurons are capable of transmitting electrical signals called ____ ____. Ion channels play a critical role in the function of nuerons.
nerve impulses ( action potentials)
Describe the direction of movement of a nerve impulse as it is triggered throught the nerve
dendrties --> axon --> terminal branches of axon
triggering of an action potential is a ____ feedback cycle
positive feedback cycle
In action potential, what step cuases more (additional) influx of Na+ ions
a slight depolarization ; opening of voltage-gated Na+ channels
Past resting membrane potential, the cell ____ in voltage and depolarizes. Post depolarization, the cell _____ in voltage and repolarization occurs
an action potential is triggered only only if the depolarization reaches the _____ level. The AP causes depolarization of the neighouring region of the plasma membrane.This in turn triggers ___ of APs along the axon
- i.e., a nerve impulse is transmitted along the axon
the speed of neural transmission on vertebrates is increased by the presense of a ____ _____
Myelin sheaths are present in segments seperated by nodes of Ranvier. In brain and spinal cord these segments are known as _____ while in typical nerve it is called _____ cells. The conduction on the impulse transmission is termed ______ conduction
Some nuerotransmitters are ______ neurotransmitters. They open ___ ____. The resulting influx of Na+ ions causes a ____ _____ of the postsynaptic membrane. Therefore the membrane potential is now closer to the threshold level.
ie. an _____________(EPSP) is briefly genertated
eg. acetylcholine, glutamate & serotonin are usually excitatory neurotransmitters
excitatory postsynaptic potential (EPSP)
Seome neurotransmitters are _____ Neurotransmitters. The open __channels or ___ channels. The resulting eflux of ___ ions or influx of ___ ions causes a slight _______ of the postsynatic membrane. Thereofore, the membrane potential is now farhter from the threshold level.
ie. an __________ (IPSP) is briefly generated
ed. GABA and glycine are usually inhibitory nuerotranmitters
opens K+ channels or Cl- channels
efflux - K+ ions ; influc Cl- ions
inhibitory postsynaptic potential (IPSP)
5 major types of gated ion channels left are involved when a neuron stimulates contraction of a skeletal muscle cell:
1) voltage-gated Ca++ channels
located in the axon terminal membrane
2) acetylcholine-gated cation channels
also called acetylcholine receptors
3) voltage-gated Na+ channels
4) voltage-gated Ca++ channels
located in the transverse tubules of the muscle cell