Chapter 9, Problem 1RQ

Summary Introduction

The genome of the virus could be in the form of single-stranded or double-stranded RNA or DNA. It also varies in size from a few kilobases to hundreds of kilobases. The RNA genome even if it is single or double-stranded, is typically smaller when compared to that of the DNA viruses. The genomes of the viruses are comparatively smaller than those of the prokaryotes.

Explanation of Solution

Escherichia coli (E.coli) is a prokaryotic organism and its genomic size is approximately found to be 4.7 Mb (Megabase).

The approximate size of the genome of T4 bacteriophage is found to be 170 kb (kilobase).

The size of the genome of T7 bacteriophage is approximately found to be 40 kb (kilobase).

• 1 megabase is equal to 1000 kilobases.

Here, the size of the E.coli genome is given as 4.7 Mb which is 4700 kilobases approximately.

Then,

The size of T4 bacteriophage in kilobases is found to be $\frac{4700}{170}=27.64\text{kb}\text{.}$

The size of T7 bacteriophage in kilobases is found to be $\frac{4700}{40}=117.5\text{kb}\text{.}$

Thus, the E.coli genome size is larger about approximately 28 times when compared to that of T4 bacteriophage and 118 times when compared to that of T7 bacteriophage respectively.