Microbiology Quiz: Bacterial Recombination and Genetics

Translation

The process in which mRNA serves as the source of information for the synthesis of proteins.

Occurs in the ribosome in the cytoplasm of prokaryotic cells, producing a polypeptide whose amino-acid sequence is determined by the mRNA codons.

Mutation

A permanent change in the base sequence of DNA.

Such changes can alter the product encoded by a gene, leading to differences in the resulting protein.

Mutagens

Agents that increase the frequency of mutation.

They may be chemical (e.g., nitrous acid, nucleoside analogs, intercalating agents) or physical (e.g., X-rays, γ-rays, UV light).

Conjugation

A process in which two bacterial cells directly exchange DNA through physical contact using sex pili (F pili) or surface molecules.

Requires direct cell-to-cell contact between opposite mating types and enables genetic transfer such as the F factor.

mRNA (Messenger RNA)

Carries coded information from DNA to ribosomes where proteins are synthesized.

Formed during transcription as a complementary copy of a gene on the DNA template.

Genome

The genetic information in the cell—the total DNA content that carries hereditary instructions.

Helicase

An enzyme that unwinds double-stranded DNA by breaking hydrogen bonds during DNA replication, allowing new strands to be synthesized.

Bacteriophage (phage)

A virus that infects bacteria.

Codon

Language of of mRNA

A triplet sequence of nucleotides on mRNA that codes for one amino acid.

Examples: start codon AUG (Methionine) and stop codons UAA, UAG, UGA.

Silent mutation

Occurs when one nucleotide is substituted for another but the new codon still codes for the same amino acid.

The protein’s function usually remains unchanged.