nbde part 1 q , need answer

[vijaggi]

1 which of the following vitamins is essential for the normal elaboration and maitenance of bone matrix ,cartilage,and dentin?
a) niacin
b)vit E
c)ascorbic acid[ans?]
d)pantothenic acid

---

Members don't see this ad.

 

[vijaggi]

I think it is strech reflex do you know the answer?

even i got answer as strecth reflex from a friend.

 

[Ice2remember]

need help with this question please.

1) An action potential initiated at the midpoint along the length of an axon will
a)Not propogate
b) propagate towards the soma.
c)propagate towards the nerve endings.
d) propagate towards both soma and nerve ending

i think the answer is C but am not so sure that it is not D.

 

[lionelhutz]

need help with this question please.

1) An action potential initiated at the midpoint along the length of an axon will
a)Not propogate
b) propagate towards the soma.
c)propagate towards the nerve endings.
d) propagate towards both soma and nerve ending

i think the answer is C but am not so sure that it is not D.

The answer is (D)

Action potentials usually go in a unidirectional way because of the refractory periods at the nodes behind them.

BUT, if an action potential is initiated in the middle of an axon that has not fired yet, no nodes (on the left or the right) are in a refractive period yet. Because of this, the potential can go towards both ends.

Sorry if I didn't explain it too well. If i had a pencil and paper to demonstrate it for you I would probably do a better job

 

[Ice2remember]

Hi lionel hutz,

Thanks so much.With your explanation the concept became very clear to me.

 

[Ice2remember]

hi friends,
need help with these questions

1) During oxidative phosphorylation,the hydrogen ion gradient is created using energy from which of the following.
A. ADP transport.
B. ATP synthesis.
C. ATP hydrolysis
D. reduction of NAD+
E. Electron transfers
My guess is the answer is E coz the series of hydrogen pumping steps(electron transfers) creates the gradient and this potential gradient is used for ATP synthesis.the answer key that i have says the answer is D.i am not sure how.

2) which of the following can increase the rate of net flux or diffusion of oxygen through the alveolar membrane?
A. decreasing the temparature.
B.increasing the cross sectional area.
C. decreasing the conc gradient.
D. increasing the path length of diffusion.
dont all the above options decrease the rate of diffusion?

3)which of the following statements BEST describes the primary role of calcium in the activation of cardiac muscle?
A. cause depolarization of the muscle.
B. couple actin and myosin to form actinomyosin.
C.reduce inhibition of tropomyosin upon the myofilaments.
D. activate myosin molecules so that it can interact with actin filaments.