Question

Bacteriophage attack of a starter culture involve a cyle of events. Among the options which is the correct sequence of events in the lytic cycle?
(A) Injection
(B) Packaging/Assembly
(C) Adsorption
(D) RNA and Protein synthesis
Choose the correct answer from the options given below:

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

Hint:

To easily remember the lytic cycle sequence:
A phage must first land and stick (Adsorption - C), inject its genes (Injection - A), manufacture parts (Synthesis - D), and finally put them together (Assembly - B).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Bacteriophages are viruses that infect and destroy bacterial cells.
In the dairy industry, phage attacks on lactic starter cultures are a major cause of slow or failed fermentations.
The lytic cycle is the process by which a phage infects a host bacterium, replicates, and lyses the cell to release new phages.

Step 2: Detailed Explanation:
Let us trace the chronological steps of the bacteriophage lytic cycle:
1. Adsorption (C): The phage first physically attaches itself to specific receptor sites on the bacterial cell wall.
2. Injection (A): Following attachment, the phage injects its viral genetic material (DNA or RNA) into the host bacterial cytoplasm, leaving its protein coat outside.
3. Synthesis (D): The host's cellular machinery is hijacked to transcribe and translate the viral genome, synthesizing viral proteins and replicating the viral genetic material.
4. Packaging and Assembly (B): The synthesized structural proteins and genetic material are assembled into complete, mature phage particles.
Eventually, the cell wall is lysed, releasing the progeny phages to infect neighboring cells.
Therefore, the correct sequence is (C) \(\rightarrow\) (A) \(\rightarrow\) (D) \(\rightarrow\) (B).

Step 3: Final Answer:
The correct sequence of events is (C), (A), (D), (B), corresponding to option 3.