-
Na+ concentration is ____ inside the cell and ____ outside the cell
- lower in the cell
- higher outside the cell
-
K+ ions are found in ____ concentration inside the cell compared to _____ concentration outside the cell.
- Higher inside the cell
- lower outside the cell
-
Mg2+ is found ____ concentration inside the cell and ___ concentration outside of the cell
- lower inside the cell
- higher inside the cell
-
Ca2+ is found in ____ concentrations inside the cell compared to ____ concentrations outside of the cell
- lower concentration inside the cell
- higher concentrations inside the cell
-
H+ is a cation found in similar concentrations but it is slightly ____ inside the cell and slightly ___ outside the cell
- higher inside the cell
- slightly lower outside the cell
-
Cl- concentration is ____ inside the cell and ____ outside the cell
- lower inside the cell
- higher outside the cell
-
substances pass across the lipid bilayer via ____ ____
simple diffusion
-
The rate that a substance will diffuse across the lipid bilayer is determined by these 2 factors;
SIZE of the substance: the smaller the substance, the higher the rate of diffusion
- lipid solubility:
- the more hydrophobic/nonpolar, the higher the rate - more important than the size, as it determines the rate of diffusion
-
Ions are highly ____ when trying to cross the phospholipid bilayer
- impermiable
- inluding amino acids
-
____ _____ proteins allow polar substances to pass across a membrane. But, these have high _____
- membrane transport proteins
- specificity
-
A solute that can not pass through a cell membrane enters the cell via ____
transporter permease; or carrier
-
Diffusion of a specific solute (usually an _____ ___) diffused through an _____ pore; a channel protein
inorganic ion; aqeous
-
uncharged substances move down the ____ gradient;
charged substances move down the ________ gradient
- concentration gradient
- electrochemical gradient
-
_____ transport requires energy input
this transport transports ____ the concentration gradient
-
Energy input for active transport comes from _____ or an ____ gradient
-
therefore, transport by channel proteins is always ___ but transport by transporters can be ___ or _____
-
This type of transport requires no membrane protein and no energy input
what is simple diffusion?
-
In transport models, the concentration of transported molecule is not affected by saturation
what is simple diffusion
-
In transport proteins, the solute adheres to the ___ ____ of the protein causing a shape change
solute-binding site
-
in____ transport, solutes are transported against the electrochemical gradient. Name 3 ways this can be acheived.
- active
- 1)Coupled transporter
- 2) ATP-driven pump
- 3) light-driven pump
-
The are _ major classes of ion channel transporters. What are they?
- 3
- uniport, symport and antiport
-
There are _ types of ATP-driven pumps found in both prokaryotic and eukaryotic pumps
4
-
This type of ATP-driven pump is found in plasma membrane of bacteria, the inner membrane of mitochondra, and thylakoid membranes of chloroplasts
F-type pump ("f" derivied from "factor")
-
these pumps use H+ gradients across these membranes to drive the synthesis of ATP
and are also known as ___ ____
- F-type pumps
- ATP-synthases
-
This type of diffusion/transport contains membrane transport proteins called Transporter pumps
Active transport
-
This type of diffusion/transport contains membrane transport proteins called Transportera and channels
Facilitated Diffusion
-
This type of diffusion/transport is the only one of its type that does NOT reach saturation
simple diffusion
-
In passive transport, a solute binds to the ____ ____ site of the membranous protein to cause a _____ change in the protein mediating the transport
solute-binding site
shape change
-
Active transport can be driven by ____. There are 3 major classes of transporters driven by ___.
ion gradients/ ion gradients
3 classes; 1)Uniport 2) symport (co-transporter) 3) Anitport (exchangers)
2 and 3 are coupled transport
-
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)
Glucose pump
-
ion gradients are established by _____ <-- ATP hydrolysis
there are _ major classes of ATP-driven pumps
- all _ major classes are found in ____prokaryotic/eukaryotic cells
- ion pumps
- 4
- 4
- both cell types
-
A __ type ion pump phosphorylates themselves during the pumping cycle
P
-
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)
- F-type pump
-
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.
- ABC transporters
- small molecules
-
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 ________
- autophosphorylation (N)
- dephosphorylation (K)
-
The Na+ - K+ pump helps the ___ ___ ____ in animal cells and regulates ____ ____ (affects movements water via osmosis through lipid bilayer and aquaporins)
- resting membrane potential
- cell volume
-
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.
- hypertonic
- hypotonic
- isotonic
-
Ion channels have an _____ pore that permits _____ of ions. They have 2 important characteristics.
1)______ 2)_____
- aqueous pore
- diffusion
- 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+
- K+ leak channels
- membrane potential
-
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 sheath
-
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
- oligodendrocytes
- Schwann cells
- Saltatory 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
- Excitory neuritransmitters
- cation channels
- slight depolarization
- 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
- inhibitory neurotransmitters
- opens K+ channels or Cl- channels
- efflux - K+ ions ; influc Cl- ions
- slight hyperpolarization
- 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
- 5) Ca++-gated Ca++ release channels
- - located in the sarcoplasmic reticulum membrane
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