1. The concentration gradient for Na+ a. Favors its movement into the cell at re
ID: 204298 • Letter: 1
Question
1. The concentration gradient for Na+
a. Favors its movement into the cell at resting potential
b. Favors its movement out of the cell at resting potential
c. Is maintained by the Na+/K+ pump
d. Both A and C
e. Both B and C
2. At an excitatory synapse
a. An action potential in the postsynaptic neuron depolarizes the presynaptic cell membrane
b. An action potential in the presynaptic neuron increase the permeability of the subsynaptic membrane of the postsynaptic cell to Na+ (as well as K+)
c.An action potential in the presynaptic neuron increase the permeability of the subsynaptic membrane of the postsynaptic cell to K+ only
d. Both A and B
e. Both A and C
3. ATP synthetase
a. Transports hydrogen ions from the matrix to the intermmebrane space (outer compartment) of the mitochondrion.
b. Is activated by the flow of hydrogen ions from the intermembrane space (outer compartment) to the matrix.
c. Converts ADP to Pi to ATP
d. Both B and C are correct
e. All of the above are correct
4. NAD+
a. Converts ADP to Pi to ATP
b. Is found only in the cytosol
c.Is an electron (or hydrogen) carrier molecule.
d. Both B and C
e. All of the above are correct
Explanation / Answer
1) D
concentration gradient of Na inside cell was-10mEq
Outside of cell was-130 mEq
So outside concentration is more when compared to inside of cell which favours the moment inside the cell through leak channels
And also more negative intracellularly compared to outside Because of positive impact of sodium favours inside moment in to the cell.
*Na-K pump makes small contribution by exporting 3Na outside for 2 potassium inside makes small contribution to Resting membrane potential.(making it slightly more negative than it would be).The action is indirect,helps in maintaining steady Na-k gradient which give rise to membrane potential to promote movement of Na and k through leak channels.
2)B
Excitatory post synaptic potential (EPSP) makes post neuron to fire a potential and continue the signal transmission.
To inhibit signal transmission (opposite of EPSP ) is inhibitory(IPSP).For the signalling process to continue the cell should be in a depolarized state to favour the progress.
The depolarization occurs when neurotransmitter is released from presynaptic neuron,it was caught by post synaptic neuron which acts as ion channels for transmission of positively charged ions (Na major ) for depolarization.
3) B
ATP synthetase helps in production of ATP.For to produce ATP the ADP and Pi should join. this is a continuous rotating nano motor ,The rotation occurs due to H+ gradient and it's movement from membrane space to matrix. While H+are Moving there is nanomotor rotational moment which joins the ADP and Pi at the stalls of machine.
4) D
NAD+ is a cofactor that required for enzymatic reactions that found only in cytosol,if any demand is present Nad+ are imported from cytosol through specific carrier proteins
In metabolism NAD+ involved in redox reactions by carrying electrons from one reaction to other (which by it reduced to NADH).The NADH can be used for donating electrons as reducing agent.it helps in transfer of electrons from one reaction to other.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.