Exam 3-Microbiology (Finished Notes)

Genome Replication

The process by which a cell duplicates its DNA prior to cell division.

Virulence

The degree of pathogenicity or disease-causing ability of a microorganism.

Transformation

Process by which a bacterium takes up free DNA from its environment and incorporates it into its own genome.

RNA polymerase

An enzyme that synthesizes RNA from a DNA template during transcription.

Polypeptide

A chain of amino acids linked by peptide bonds, forming part of a protein.

Central Dogma

The flow of genetic information from DNA to RNA to protein.

Codon

A sequence of three nucleotides that corresponds to a specific amino acid or a stop signal during protein synthesis.

Operon

A cluster of genes under the control of a single promoter, allowing coordinated expression.

Repressor

A protein that inhibits gene expression by binding to the operator region of an operon.

Transposon

A DNA sequence that can change its position within the genome, potentially disrupting genes and altering the genome's function.

Splicing

The process of removing introns and joining exons in a pre-mRNA molecule to form mature mRNA.

Ames Test

A biological assay to assess the mutagenic potential of chemical compounds.

Chaperones

Proteins that assist in the proper folding of other proteins.

Hfr Cell

A cell with a high frequency of recombination due to the presence of an integrated F plasmid.

Competent Cells

Bacterial cells that are capable of taking up foreign DNA from their environment.

DNA Repair Mechanisms

Various cellular processes that correct damage to DNA molecules.

Horizontal Gene Transfer

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

Eukaryotic RNA polymerases

Different types of RNA polymerases in eukaryotic cells, responsible for synthesizing different types of RNA.

Semiconservative Replication

The mechanism of DNA replication in which each new double helix contains one original and one newly synthesized strand.

Genome Replication

The process by which a cell copies its entire genome to produce two identical sets.

Virulence

The degree to which a pathogen can cause disease.

Transformation

The genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material.

DNA polymerase

An enzyme that synthesizes DNA molecules from nucleotide building blocks.

Nucleotides

The basic building blocks of nucleic acids, consisting of a nitrogenous base, a sugar, and a phosphate group.

Semi-Conservative Replication

The mechanism by which DNA is replicated in all known cells, where each strand of the original double helix serves as a template for a new strand.

RNA polymerase

An enzyme that synthesizes RNA from a DNA template during transcription.

Operon

A cluster of genes under the control of a single promoter, allowing for coordinated expression.

Lactose Operon

An operon required for the transport and metabolism of lactose in bacteria.

Point Mutation

A genetic mutation where a single nucleotide base is changed, inserted, or deleted.

Ribosome

A complex molecular machine found within all living cells that serves as the site of biological protein synthesis (translation).

mRNA

Messenger RNA; a type of RNA molecule that carries genetic information from DNA to ribosomes for protein synthesis.

tRNA

Transfer RNA; a type of RNA molecule that helps decode a messenger RNA sequence into a protein, by carrying specific amino acids to the ribosome.

Helicase

An enzyme that unwinds the DNA double helix during DNA replication, transcription, and repair by breaking hydrogen bonds between the bases.

DNA Ligase

An enzyme that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.

Conjugation

A process of horizontal gene transfer in bacteria where genetic material is transferred between bacterial cells by direct cell-to-cell contact.

Promoter

A DNA sequence to which RNA polymerase binds to initiate transcription of a gene.

Fred Griffith’s Experiment

An experiment that demonstrated that genetic material could be transferred between bacteria, illustrated by the transformation of non-virulent R strain into virulent S strain.

Transformation

The process by which a cell takes up naked DNA from the environment, which can result in a change in genotype and phenotype.

Oswald Avery’s Experiment

An experiment that concluded DNA was the transformation factor, which transformed R strain bacteria to S strain after destruction of DNA.

Semi-Conservative DNA Replication

A method of replication in which each daughter DNA molecule consists of one old strand and one new strand.

Origin of Replication

The specific region on a DNA molecule where replication begins.

Leading Strand

The continuously synthesized DNA strand during replication that is oriented in the same direction as the replication fork.

Lagging Strand

The DNA strand that is synthesized discontinuously in short segments called Okazaki fragments.

Chaperones

Proteins that assist in the proper folding of other proteins during synthesis.

Operons in Bacteria

A cluster of genes under the control of a single promoter, allowing multiple genes to be expressed together.

Lac Operon

A set of genes involved in the metabolism of lactose, which is regulated by the presence and absence of lactose.

Mutations

Changes in the DNA sequence that can lead to genetic diversity, affecting the phenotype of an organism.

Point Mutations

A change in a single nucleotide that can lead to different types of mutations like silent, missense, and nonsense mutations.

Ames Test

A test that uses bacteria to determine if a substance is a mutagen by measuring reversion rates of auxotrophs.

DNA Repair Mechanisms

Processes by which cells identify and correct damage to the DNA molecules that encode their genomes.

Horizontal Gene Transfer

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

Conjugation

A method of genetic transfer in bacteria that involves direct contact between cells, commonly facilitated by a sex pilus.

Transduction

The process of transferring genetic material from one bacterium to another via a bacteriophage (virus).

Transposable Elements

Segments of DNA that can move from one location in the genome to another, also known as 'jumping genes'.

Eukaryotic Gene Expression Regulation

Complex regulatory mechanisms involving multiple RNA polymerases and modifications like splicing and capping.

Housekeeping Genes

Genes that are always required for the maintenance of basic cellular function, usually expressed at a constant level.

Inducible Genes

Genes that can be turned on or off in response to environmental changes, often regulated by small molecules.

Repressible Genes

Genes that are usually on but can be turned off by the presence of specific molecules.

Rho-Dependent Termination

A termination mechanism for transcription in bacteria that relies on the Rho protein to disengage RNA polymerase.

Genome Replication

The process by which a cell makes a copy of its DNA.

Virulence

The degree of pathogenicity of a microorganism.

Transformation

The genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material.

Plasmids

Small, circular, double-stranded DNA molecules separate from chromosomal DNA and can replicate independently.

Central Dogma

The process by which the information in genes flows into proteins: DNA -> RNA -> Protein.

Nucleotides

The basic building blocks of nucleic acids, DNA and RNA.

RNA Polymerase

An enzyme that synthesizes RNA from a DNA template.

Operator

A segment of DNA that a repressor binds to, thereby inhibiting the transcription of nearby genes.

Repressor

A protein that suppresses the expression of a gene.

Operon

A cluster of genes under the control of a single promoter.

Mutations

Permanent changes in the DNA sequence that can lead to genetic diversity.

Ames Test

A test used to assess the mutagenic potential of chemical compounds.

Conjugation

A process by which one bacterium transfers genetic material to another through direct contact.

Transduction

The transfer of DNA from one bacterium to another via a virus.

Competent Cells

Cells that are able to take up foreign DNA from their environment.

Peptide Bonds

Covalent bonds that link amino acids together to form proteins.

Exons and Introns

Exons are coding sequences in a gene, while introns are non-coding sequences.