Question

The bacteriophage $\varphi \times 174$ differs from other organisms in having

• A. single stranded DNA, as hereditary material
• B. RNA as hereditary material
• C. both DNA and RNA, as hereditary material
• D. DNA as hereditary material

Answer 1

Answer: (A)

The $E$. coli phage $\varphi \times 174$ is ss-DNA phage. It does not contain any non-DNA component and is completely degraded by nuclease. RNA is present as genetic material in $\varphi 2$ phages and $\varphi 6$ phages and plant viruses also contain RNA as their genetic material.
The phages which have double stranded DNA as their genetic material are $T$ even phages of E. coli $\left(T_2,T_4,T_6\right)$, $T$-odd phages of E.coli $\left(T_1,T_3,T_5,T_7\right)$ etc.