Question

Arrange the following bacteriophages in the increasing order of size in terms of nucleotide base pairs
(A). T4 phage
(B). \(\lambda\) phage
(C). T7 phage
(D). \(\phi\)X174 phage
Choose the correct answer from the options given below:

• A. (A), (B), (C), (D).
• B. (A), (B), (D), (C).
• C. (D), (C), (B), (A).
• D. (C), (B), (D), (A).

Hint:

For exams, it's useful to memorize the relative sizes of common model organisms and vectors. Remember \(\phi\)X174 is tiny and single-stranded, the T-phages (T7, T4) are generally larger with T4 being a classic example of a large, complex phage, and \(\lambda\) sits in the middle.

Answer 1

The Correct Option is C

Step 1: Introduction:
The task is to order four bacteriophages by increasing genome size (nucleotides or base pairs). Bacteriophages are viruses that infect bacteria and have variable genome sizes.
Step 2: Genome Sizes:
The approximate genome sizes are:
(D) \(\phi\)X174 phage: 5,386 nucleotides (single-stranded circular DNA).
(C) T7 phage: 40,000 base pairs (40 kb) (linear double-stranded DNA).
(B) \(\lambda\) phage: 48,500 base pairs (48.5 kb) (linear double-stranded DNA).
(A) T4 phage: 169,000 base pairs (169 kb) (linear double-stranded DNA).
Step 3: Solution:
The increasing order of genome size is: \(\phi\)X174 (\(\sim\)5.4 kb) \(<\) T7 (\(\sim\)40 kb) \(<\) \(\lambda\) (\(\sim\)48.5 kb) \(<\) T4 (\(\sim\)169 kb).
This corresponds to the sequence (D), (C), (B), (A).