Microbial Genetics and Evolution

A set of flashcards covering key concepts in microbial genetics, focusing on bacterial evolution, genome structure, genetic exchange processes, and virus classification.

What is the primary driver of bacterial evolution according to microbial genetics?

Mutation and gene transfer.

Which organism is referred to as a model organism for genetic studies?

Escherichia coli.

What is a haploid genome?

A genome that has only one copy of each gene.

What are dominant mutations?

Mutations that manifest their effects even when only one copy is present.

What is transduction in microbial genetics?

The transfer of genetic material between bacteria via bacteriophages.

What is conjugation?

The transfer of plasmid DNA from one bacterial cell to another through a pilus.

What is transformation in bacterial genetics?

The uptake of free DNA from the environment by a bacterial cell.

What is a plasmid?

A small, circular piece of DNA independent of chromosomal DNA in bacteria.

What role do restriction enzymes play in bacteria?

They degrade incoming foreign DNA, providing a defense against phages.

What does the term merodiploid refer to?

A bacterial cell that has two copies of some gene sequences, resulting from the acquisition of extra genetic material.

What is the significance of the F-plasmid in E. coli?

It promotes conjugation and gene transfer between bacterial cells.

What is horizontal gene transfer?

The transfer of genetic material between organisms in a manner other than traditional reproduction.

What are insertion sequences (ISs)?

The simplest transposable elements that carry no other sequences besides those required for transposition.

What is the function of transposase?

An enzyme that facilitates the movement of transposable elements within and between DNA molecules.

What is specialized transduction?

The transfer of specific bacterial DNA by a lysogenic bacteriophage.

What is a prophage?

The integrated form of a bacteriophage genome within a bacterial chromosome.

How do bacteriophages typically transfer DNA?

By lytic cycles that cause the bacterial cell to lyse.

What is an example of a naturally competent bacterium?

Bacillus species.

How do mutations affect prokaryotes compared to eukaryotes?

Prokaryotes have a higher frequency of fixed mutations due to less efficient DNA repair mechanisms.

What is the Baltimore classification system?

A way of categorizing viruses based on their genome structure and replication strategies.

What do (+) sense RNA genomes refer to in the context of Baltimore classification?

RNA genomes that can serve directly as mRNA for protein synthesis.

What are the two main types of transposable elements?

Insertion sequences (ISs) and transposons.

What is the outcome of an excision error in bacterial genetics?

It may lead to the formation of a chimeric phage genome.

What contributes to the extreme diversity of virus genomes?

Variations in size, nucleic acid type, conformation, gene copy number, and coding strategy.