Biology Microbiology and Biotechnology Flashcards

Which of the following best describes the lytic cycle of a bacteriophage?

Answer: The phage replicates within the host and lyses the cell to release new phages

In the lytic cycle, the phage hijacks the bacterial cell's machinery to replicate, then destroys (lyses) the host cell to release new phage particles.

What is the function of telomerase in cancer cells?

Answer: It extends telomeres, preventing cellular senescence

Telomerase extends telomeres at the ends of chromosomes, allowing cancer cells to divide indefinitely without entering replicative senescence.

Which biosafety level (BSL) is required for working with agents that pose a high risk of life-threatening disease with no vaccine or therapy?

Answer: BSL-4

BSL-4 laboratories handle the most dangerous pathogens (e.g., Ebola, Marburg) that pose a high risk of aerosol-transmitted infection with no available treatment.

What is the role of Taq polymerase in PCR?

Answer: It synthesizes new DNA strands at elevated temperatures

Taq polymerase, isolated from Thermus aquaticus, is a heat-stable DNA polymerase that synthesizes new DNA during the extension step of PCR at ~72°C.

Which type of symbiosis describes the relationship between nitrogen-fixing Rhizobium bacteria and legume roots?

Answer: Mutualism

Rhizobium and legumes share a mutualistic relationship: the bacteria receive carbon from the plant while fixing atmospheric nitrogen for the plant's use.

Monoclonal antibodies used in cancer therapy are produced by which type of cell?

Answer: Hybridoma cells

Hybridoma cells, formed by fusing a specific antibody-producing B cell with a myeloma (cancer) cell, produce large quantities of identical monoclonal antibodies.

What does the term 'plasmid curing' refer to in microbiology?

Answer: Eliminating a plasmid from a bacterial population

Plasmid curing is the process of removing or eliminating a plasmid from bacterial cells, often achieved through heat treatment, acridine dyes, or other agents.