Question

Microbiology

1. Which type of phage infection can cause specialized transduction?

2. When protein synthesis initiates, does the first tRNA bind in the A-site, E-site, or P-site of the ribosome?

3. TRUE OR FALSE: A persistent viral infection that continuously produces infectious viral particles is called a CHRONIC infection.

Answer 1

1. The process by which a foreign DNA material is introduced into a cell by a virus or a viral vector. There are two types of transduction, Generalized and Specialized. In generalized any bacterial gene can be transferred to a second bacterium through a bacteriophage while in specialized transduction a restricted set of bacterial genes are transferred to another bacterium. Infection caused by specialized transducing phages cause specialized transduction. Lambda phage is a good example of specialized transducing phage. It has been a major importance in the study of specialized transduction.

2. Protein synthesis is a process in which cells make proteins. It is a  core biological process which occurs inside the cells balancing loss of cellular proteins by producing new ones. It occurs in two stages: Transcription and Translation.

When a protein synthesis initiates the tRNA first binds to the A-site (aminocyl) in the ribosome. The P-site (peptidyl) is the second binding site for tRNA while E-site (exit) is the third binding site of tRNA in the ribosome.

3. TRUE

Explanation: Persistant infections are the infections in which virus is not cleared but remains in specific cells of infected individuals. Persistant infections are distinguished into three types. 1. Chronic focal infection. 2. Chronic diffuse infection and 3. True latent infection.

In chronic focal infection only sall portion of cells are infected, these cells release viruses and are killed. such infections can be cured by antiviral antibody, interferron or non specific inhibitor. Chronic diffuse infections are steady state infections in which all of the cells are infected and both cells and virus ultiplies without cells being killed. In this the cells continously produces infectious virus particles and infection cannot be eliminated by antiviral antibodies.

Third type is so called true latent infection, in which viral infection is replicated and seggregated to daughter cells either inside the chromosomes or extrachromosomally.