Intro to Genetics and Microbiology

Comprehensive vocabulary terms covering genetics, DNA replication, gene regulation, mutations, gene transfer mechanisms, and biotechnology basics.

Genetics

Study of what genes are, how they carry information, how information is expressed, and how genes are replicated

Gene

Segment of DNA that encodes a functional product, usually a protein

Genome

All of the genetic material in a cell

Genomics

Molecular study of genomes

Genotype

Genes of an organism

Allele

Variant of a gene

Phenotype

Expression of the genes

DNA Polymerase

Enzyme that copies DNA in the $5' \rightarrow 3'$ direction and is involved in repairing mutations through nucleotide excision

RNA primer

A short RNA sequence synthesized by primase that initiates DNA synthesis

Leading strand

The DNA strand that is synthesized continuously by DNA polymerase

Lagging strand

The DNA strand that is synthesized discontinuously

Okazaki fragments

The discontinuous fragments of the lagging strand that are joined by DNA ligase

DNA ligase

Enzyme that joins the discontinuous fragments of the lagging strand or unites the backbones of two DNA fragments to produce recombinant DNA

Conjugative plasmid

A plasmid that carries genes for sex pili and transfer of the plasmid

Dissimilation plasmids

Plasmids that encode enzymes for catabolism of unusual compounds

R factors

Plasmids that encode antibiotic resistance

Transcription

The process of making RNA ($mRNA$, $tRNA$, and $rRNA$) from a DNA template

Codon

A sequence of $3$ nucleotides in $mRNA$ that corresponds to one amino acid

Shine Dalgarno sequence

A specific sequence in $mRNA$ involved in the initiation of translation by the ribosome

Constitutive enzymes

Enzymes that are expressed at a fixed rate

Operon

A system consisting of promoter ($P$) and operator ($O$) sites and structural genes that code for proteins, regulated by a regulatory gene ($I$)

Lac Operon

An example of an inducible operon where allolactose binds the repressor to trigger a conformational change so it no longer binds the operator

DNA Polymerase Fidelity

The ability to make an exact copy of the chromosome

Mutagen

An agent that causes mutations

Spontaneous mutation rate

The rate of mutations occurring in the absence of a mutagen, typically $1$ in $10^9$ replicated base pairs or $1$ in $10^6$ replicated genes

Base substitution

A point mutation involving a change in one base

Silent mutation

A base substitution that results in no amino acid change

Missense mutation

A base substitution that results in a change in the amino acid

Nonsense mutation

A base substitution that results in a nonsense codon

Frameshift mutation

The insertion or deletion of one or more nucleotide pairs

Vertical gene transfer

Gene transfer that occurs during reproduction, between generations of cells

Horizontal gene transfer

Transfer of genes between cells of the same generation

Conjugation

The transfer of an $F$ factor (plasmid) from a donor ($F^+$) to a recipient ($F^-$) cell through a sex pilus

Transduction

The process where bacterial DNA is packaged into a phage capsid and transferred to a new host cell

Competent bacteria

Bacteria that have receptors for DNA incorporation or holes in the cell membrane allowing DNA in

Transposons

Segments of DNA that can move from one region of DNA to another; they contain insertion sequences for cutting and resealing DNA using transposase

Recombinant DNA technology

A set of techniques for combining genes from different sources into a single DNA molecule

Vector

Self-replicating DNA, such as a plasmid or virus, used to carry a desired gene to a new cell

Clone

A population of genetically identical cells arising from one cell, each carrying the new gene

Restriction Enzymes

Enzymes that cut specific sequences of DNA and destroy bacteriophage DNA in bacterial cells without digesting host DNA that has methylated cytosines