Some viruses can be crystallized and their structures analyzed. one such virus is yellow mottle virus, which infects beans. this virus has a single-stranded rna genome containing about 6,300 nucleotides. its capsid is 25-30 nm in diameter and contains 180 identical capsomeres.
1) if the yellow mottle virus capsid has 20 facets, how many proteins form each facet?
a) 1
b) 5
c) 9
d) 20
e) 180

The correct answer is c. That is 9 protein to form each facet

Explanation:

Given that the capsids is 25-30nm in diameter and it contains 180 identical capsomeres, if the virus capsid has 20 facets in 180 capsomeres, then for each protein facet, it will contain 9 protein facets.

Thai is 180 capsomeres divided by total number of facets (20).

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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