In this Graph showing growth curve of viruses that attack bacteria, Vertical line ( RED Arrow) indicate
A. Latent period.
B. Synthetic period.
C. Burst size.
D. Eclipse phase.
Ans:C. Burst Size.
This graph is One-Step growth curve of bacteriophage
Ans is Burst size
- Viruses that attack bacteria are called bacteriophages .
- Stages of one step growth curve of bacteriophage.
- Eclipse: or initial period can be defined as the time period taken for the appearance of first intracellular phages. No phage particles can be detected during this period as the phages are being uncoated and phage DNA is being injected foe replication.
- Synthetic period: During synthetic period intracellular particles are being produced. As in the Eclipse period, there are no phage particles released during the synthetic period.
- Latent Period: The first two periods are combined in the third period known as latent period. The latent period is described as the time period prior to the release of infection particles or appearance of extra cellular phages.
- In the latent period, attachment, entry, replication, transcription, translation and assembly of progeny phages occur.
- Rise Period: In this period lysis occurs and extracellular phages appear and they increase in number of concentration of bacteriophages rises.
- A rise in plaque forming units (pfu) to a plateau level occurs as bacteria are lysed and the newly synthesized phage are released into the medium. These phage particles fail to meet susceptible bacteria (due to the dilution of the adsorption mixture) and thus remain free in the culture fluid. The average number of phage released per bacterium is called the burst size.