Question

A nucleosome is composed of 9 histones (1H1, 2H2A, 2H2B, 2H3, and 2H4)

Select one:

a. False

b. True

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We established that many growth factors activate the cell cycle by binding to receptor tyrosine kinases (RTK). Sometimes, these RTKs get mutated, and permanently turned “ON.” As a result, the cell cycle is stimulated even in the absence of growth factors. In light of this information, you would label the genes that encode for these RTKs as

Select one:

a. Tumor suppressor genes

b. Proto-oncogenes

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At the end of the G2 phase, a diploid cell with an n=4 has a total of _____ chromosomes

Select one:

a. 16

b. 8

c. 4

d. 32

Answer 1

1. False

Nucleosome is made up of 8 molecules of histone proteins.

Two molecules each of H2A and H2B combine to form a tetramer.

Two molecules each of H3 and H4 combine to form a tetramer.

These two tetramer combine to form octamer.

2. Proto oncogenes

The RTK gene is now permanently on. It means it has got a gain of function mutation.

Proto oncogenes get a gain of function mutation to form cancer.

Tumor suppressor genes get a loss of function mutation to form cancer.

3. 8

If n = 4, than 2n = 8

The number of chromosomes before and after G2 remains same. The cell will be diploid.

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