Study Prep: Microbial Genetics Summary

These flashcards summarize key concepts in microbial genetics, including foundational experiments and mechanisms of gene transfer.

What did Frederick Griffith's 1928 experiment demonstrate?

Griffith's experiment identified that some unknown genetic factor controls traits of organisms, showing bacteria can transform genetic material.

What is transformation in microbiology?

The uptake of external DNA by a cell, resulting in a genotypic and phenotypic change.

What was the transforming substance identified in Griffith’s experiment?

DNA was identified as the transforming substance by later work of Avery, McCarty, and MacLeod.

What did the Hershey-Chase experiment confirm was the genetic material?

The Hershey-Chase experiment confirmed that DNA, not protein, is the genetic material.

What are Chargaff's Rules regarding DNA base composition?

For each species, the % of A and T bases are roughly equal, as are the % of G and C bases.

What did Rosalind Franklin’s X-ray diffraction help discover?

The structure of DNA as a double helix.

What is the central dogma of molecular biology?

The flow of information from DNA to RNA to protein.

What is alternative RNA splicing?

A process that allows a single gene to produce multiple protein products by splicing different combinations of exons.

What is the role of RNA polymerase in transcription?

RNA polymerase synthesizes RNA using a DNA template.

What are the three main types of horizontal gene transfer in bacteria?

Transformation, transduction, and conjugation.

What is the function of transposons in prokaryotes?

Transposons, or jumping genes, allow pieces of DNA to move within and between genomes.

What is the Ames test used for?

The Ames test is used to determine if a chemical is a mutagen.

What is the purpose of the SOS repair system in bacteria?

The SOS system is used to repair extensively damaged DNA, but it is error-prone.

How does glucose affect the lac operon?

High glucose levels inhibit the expression of the lac operon.

What is the difference between indused and repressible operons?

Inducible operons are normally off but can be turned on, while repressible operons are normally on but can be turned off.

What is CRISPR-Cas?

A bacterial defense mechanism that stores fragments of viral DNA to defend against future infections.