Module 6: Microbial Genetics Overview

Anticodon

A sequence of three bases on tRNA complementary to a codon on mRNA, ensuring correct amino acid placement.

Central Dogma

Flow of genetic information in cells: DNA → RNA → Protein.

Chromosome

A DNA molecule containing genes and associated proteins, responsible for genetic inheritance.

Codon

A three-nucleotide sequence on mRNA that specifies a single amino acid.

Complex transposon

A transposon containing additional genes (e.g., antibiotic resistance) besides those required for transposition.

Conjugation

A form of horizontal gene transfer where DNA is transferred between bacteria via a pilus.

DNA

The molecule that stores genetic information in cells, composed of nucleotides (A, T, C, G).

DNA polymerase

Enzyme responsible for synthesizing DNA by adding nucleotides to the growing strand during replication.

Frameshift mutation

A mutation caused by the insertion or deletion of nucleotides, shifting the reading frame.

Genetic code

The set of rules by which codons in mRNA specify amino acids during protein synthesis.

Genetics

The study of heredity and variation in organisms.

Genome

The complete set of genetic material in an organism.

Genomics

The study of entire genomes, including gene sequences and functions.

Genes

Segments of DNA encoding functional products, usually proteins.

Genotype

The genetic composition of an organism.

Horizontal gene transfer

The transfer of genetic material between organisms of the same generation.

Lagging strand

The DNA strand synthesized discontinuously in short fragments (Okazaki fragments) during replication.

Leading strand

The DNA strand synthesized continuously during replication.

Missense mutation

A mutation that changes a single amino acid in a protein.

Mobile genetic elements

Segments of DNA that can move between different locations within a genome.

mRNA (messenger RNA)

RNA molecule that carries genetic information from DNA to the ribosome for protein synthesis.

Mutagen

An agent that causes mutations (e.g., chemicals, radiation).

Mutation

A change in the nucleotide sequence of DNA.

Nonsense codon

A codon that signals the termination of protein synthesis (e.g., UAA, UAG, UGA).

Nonsense mutation

A mutation that converts an amino acid codon into a stop codon, prematurely ending translation.

Nucleotides

Building blocks of DNA and RNA, composed of a sugar, phosphate group, and nitrogenous base.

Phenotype

The observable traits or characteristics of an organism.

Plasmids

Small, circular DNA molecules in bacteria that replicate independently of the chromosome.

Promoter

A DNA sequence where RNA polymerase binds to initiate transcription.

Replication fork

The Y-shaped region where DNA replication occurs.

R-factors

Plasmids that carry genes for antibiotic resistance.

RNA polymerase

Enzyme that synthesizes RNA from a DNA template during transcription.

rRNA (ribosomal RNA)

RNA component of ribosomes, involved in protein synthesis.

Semiconservative replication

DNA replication where each daughter molecule consists of one original strand and one new strand.

Sense codon

Codons that specify amino acids in the genetic code.

Simple transposon

A transposon with only the genes necessary for transposition.

Spontaneous mutation

Mutations that occur naturally without external influences.

Terminator

A DNA sequence signaling the end of transcription.

tRNA (transfer RNA)

RNA molecule that delivers amino acids to ribosomes during translation.

Transcription

The process of synthesizing RNA from a DNA template.

Transduction

Horizontal gene transfer where bacterial DNA is transferred by a virus (bacteriophage).

Translation

The process of synthesizing proteins from mRNA on ribosomes.

Transposons

Mobile genetic elements that can move within a genome.

Vertical gene transfer

Transfer of genetic material from parent to offspring.

What is the primary function of DNA in a cell?

B. Stores genetic instructions for protein and RNA synthesis.

What are the base-pairing rules in DNA?

C. A-T, C-G.

Which enzyme is responsible for adding nucleotides during DNA replication?

B. DNA polymerase.

What is the function of RNA polymerase?

B. Synthesizes RNA from a DNA template.

What is the purpose of transcription?

C. Synthesizes mRNA from DNA.

Where does translation occur in bacterial cells?

B. Ribosomes.

What is a codon?

A. A three-nucleotide sequence on mRNA that codes for an amino acid.

What is the role of tRNA in protein synthesis?

A. Carries amino acids to the ribosome.

tRNA

Carries amino acids to the ribosome​

Missense mutation

A mutation that alters one amino acid in the protein sequence.

Nonsense mutation

A mutation where a stop codon replaces an amino acid codon, creating premature stop codons, leading to incomplete proteins.

Horizontal gene transfer

Transfer of genetic material between bacteria without reproduction, occurring within the same generation.

Transformation

The uptake of free DNA fragments from the surroundings by bacterial cells.

Conjugation

The process of DNA transfer between bacteria by direct cell-to-cell contact via a pilus.

Bacteriophages

Viruses that infect bacteria and facilitate transduction by transporting DNA between bacteria.

Plasmids

Small, circular DNA molecules that replicate independently and often carry non-essential genes, like antibiotic resistance genes.

Transposons

DNA sequences that can move within or between DNA molecules, also known as 'jumping genes'.

R-factor

A plasmid carrying antibiotic resistance genes that allows bacteria to resist antibiotics.

Leading strand

The strand of DNA that is synthesized continuously during replication.

Promoter

The DNA sequence where RNA polymerase binds to start transcription.

Semiconservative DNA replication

A process where each new DNA molecule consists of one original and one new strand.