Microbial genetics ：練習問題

Which of the following characteristics of bacteria makes them particularly suitable for the mass production of human therapeutic proteins in microbial genetics?

A student performed a transformation experiment by mixing E. coli with a plasmid containing a gene for tetracycline resistance. If the transformation was successful, which of the following results would be expected on an agar plate containing tetracycline?

When engineering genetically modified bacteria to produce human insulin, scientists must use reverse transcriptase to synthesize cDNA from human mRNA. Why is this step necessary?

In the context of microbial genetics, what is the primary purpose of including a selectable marker (e.g., an antibiotic resistance gene) in a recombinant plasmid?

A scientist observes that a recombinant plasmid carrying a pesticide-resistance gene has transferred from a genetically modified soil bacterium to a different, indigenous bacterial species. This process is an example of:

How can microbial genetics be utilized to engineer yeast strains that are more suitable for industrial-scale bioethanol production under high-temperature conditions?

Explain why a genetically modified bacterium carrying a human insulin gene may exhibit a slower growth rate compared to its wild-type counterpart, using the concept of metabolic burden.

In the process of creating genetically modified bacteria, explain why the transformation efficiency necessitates the use of a marker gene within the plasmid vector.

The release of genetically modified (GM) microorganisms into the environment is a major concern in microbial genetics. To mitigate risks, scientists may engineer auxotrophic strains.
(a) Define auxotrophy and explain how an auxotrophic bacterium differs from a wild-type bacterium.
(b) Explain how the use of auxotrophic strains serves as a biological containment strategy to prevent the uncontrolled spread of recombinant DNA in the event of an accidental laboratory leak.

A biotechnology company is designing a genetically modified (GM) bacterium to produce human growth hormone. The process involves inserting the human gene into a bacterial plasmid.
(a) Draw and label a diagram of the recombinant plasmid, showing the essential components: the target gene, a promoter, and a selectable marker (such as an antibiotic resistance gene).
(b) Explain the specific role of the selectable marker in the transformation process.
(c) Discuss two potential environmental hazards or biosafety risks associated with the accidental escape of these GM bacteria into local water systems.