List of top Microbiology Questions

Staining material of gram positive bacterium is

Mycoplasmas are different from the other prokaryotes by

A polymerase chain reaction (PCR) based diagnosis test was performed on a bacterial sample targeting a specific gene. There are 3 copies of this gene in the bacterial genome. Prior to DNA extraction, the bacteria were incubated to allow one cycle of growth. 3072 amplicon copies were obtained after 9 cycles of the PCR. Assume 100% efficiency at each step. The initial bacterial count in the sample was ....... (Answer in integer)

The doubling time of {Escherichia coli is 30 minutes in a culture medium containing glucose and yeast extract. Phage T7 has a life cycle of 20 minutes and a burst size of 200 phage per infected {E. coli} cell. Phage absorption is instantaneous and occurs at 1 multiplicity of infection (MOI). Bacteria infected with multiple or single phage give the same burst. 5000 plaque forming units of T7 phage are added to a culture of \( 2 \times 10^7 \) {E. coli} cells. Assuming normal division, the {E. coli} culture will lyse completely by ........ full cycles of bacterial division. (Answer in integer)}

Which of the following bacteria is the most common cause of community-acquired pneumonia?

The doubling time of Escherichia coli is 30 minutes in a culture medium containing glucose and yeast extract. Phage T7 has a life cycle of 20 minutes and a burst size of 200 phage per infected E. coli cell. Phage absorption is instantaneous and occurs at 1 multiplicity of infection (MOI). Bacteria infected with multiple or single phage give the same burst. 5000 plaque forming units of T7 phage are added to a culture of \( 2 \times 10^7 \) E. coli cells. Assuming normal division, the E. coli culture will lyse completely by ........ full cycles of bacterial division. (Answer in integer)}

Which option(s) correctly match(es) the structures in a bacterial cell (Column I) with their corresponding functions (Column II)?

The adaptive immune response in an animal involves the generation of antibodies against an invading bacterial pathogen. The following graph represents antibody titer levels in a mammal exposed twice to the pathogen.
Which one of the following options correctly pairs antibodies to peak I and peak II in the graph?

A penicillin sensitive Escherichia coli population is exposed to a lethal dose (200 µg/ml) of penicillin. Assuming density-independent mortality, which one of the following relationships would describe the number of surviving bacteria (N) over time (T)?

Correctly match the bacterial type in Column I with their corresponding environmental niche in Column II: