Question

1. A phage with a genome of 10,000 base pairs has a Cot 1/2 value of 5. What is the expected Cot 1/2 of a phage with a 5,000 base pair genome?   

A.   5    

B.   2.5    

C.   cannot be determined with the information provided    

D.   10

2. How many histones are combined with the DNA in the histone core?    

A.   9   

B.   5

  C.   4    

D.   8

please help

Answer 1

1. 10

Phage contains ssDNA as its genome.

There is an inverse relation between Cot value and # of bases in DNA.

Cot is the product of concentration (Co) and time (t).

More the # of repetitive sequences in DNA, lower is the Cot value.

For the given question, we can assume than the DNA with 10,000 bases has more amount of repetitve sequences than the DNA with 5000 bases.

5 / x = 5000 / 10,000

x = 10

2. 8

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 tetramers combine to form an octamer or the nucleosome particle.

Two octamers are connected to each other by H1 linker histone.

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