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: Understanding the Concept:
Bacteriophages, viruses that infect bacteria, have genomes of varying sizes and compositions. The question asks to arrange four well-known bacteriophages in order of increasing genome size, measured in nucleotides or base pairs.
Step 2: Detailed Explanation:
Let's list the approximate genome sizes of the given phages:
(D) \(\phi\)X174 phage: This is a very small phage with a single-stranded circular DNA genome. Its genome size is 5,386 nucleotides.
(C) T7 phage: This phage has a linear double-stranded DNA genome with a size of approximately 40,000 base pairs (40 kb).
(B) \(\lambda\) phage: This is a well-studied phage with a linear double-stranded DNA genome of approximately 48,500 base pairs (48.5 kb).
(A) T4 phage: This is a large and complex phage with a linear double-stranded DNA genome of approximately 169,000 base pairs (169 kb).
Step 3: Final Answer:
Arranging these phages in increasing order of their genome size gives:
\(\phi\)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).