Define plaque, lysogeny, and prophage.

Verified step by step guidance

1. Step 1: Define 'plaque' in the context of bacteriophages. A plaque is a clear area on a bacterial lawn (a layer of bacteria grown on an agar plate) where bacteriophages have infected and lysed the bacterial cells, resulting in a visible zone of clearing.
2. Step 2: Explain 'lysogeny'. Lysogeny is a process where a bacteriophage integrates its genetic material into the host bacterium's genome, becoming a prophage. In this state, the phage DNA is replicated along with the host DNA without causing lysis of the host cell.
3. Step 3: Define 'prophage'. A prophage is the form of a bacteriophage when its DNA is integrated into the host bacterium's genome during the lysogenic cycle. The prophage can remain dormant within the host genome until certain conditions trigger its reactivation.
4. Step 4: Discuss the relationship between these terms. Plaques are the result of the lytic cycle of bacteriophages, while lysogeny and prophage are part of the lysogenic cycle, where the phage DNA is incorporated into the host genome without immediate destruction of the host.
5. Step 5: Highlight the significance of these concepts in genetics. Understanding plaques, lysogeny, and prophages is crucial for studying bacteriophage life cycles, bacterial genetics, and the mechanisms of horizontal gene transfer.

Key Concepts

Plaque

In microbiology, a plaque refers to a clear zone that appears on a bacterial lawn due to the lysis of bacteria by bacteriophages. When a bacteriophage infects a bacterium, it replicates and eventually causes the bacterium to burst, releasing new phages. This results in a visible area devoid of bacteria, which can be counted to determine the concentration of phages in a sample.

Lysogeny

Lysogeny is a viral replication cycle in which a bacteriophage integrates its genetic material into the host bacterium's genome, becoming a prophage. In this state, the viral DNA is replicated along with the host's DNA during cell division, allowing the virus to persist without killing the host. This can lead to a stable relationship between the virus and the host until conditions trigger the lytic cycle.

Prophage

A prophage is the dormant form of a bacteriophage that has integrated its DNA into the host bacterium's chromosome during the lysogenic cycle. In this state, the prophage is replicated along with the host's DNA and can remain inactive for extended periods. Environmental factors or stress can induce the prophage to enter the lytic cycle, leading to the production of new phages and the eventual lysis of the host cell.