Regulation of Transcription and Mutations in Prokaryotes

These flashcards cover key concepts from the lecture on transcription regulation and mutation in prokaryotes.

Transcription regulation in prokaryotes

The process by which the expression of genes is controlled, often involving operons.

Operon system

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

Inducible operon

Operons that are activated by the presence of an inducer, e.g., the lactose operon.

Repressible operon

Operons that are inhibited by the presence of a corepressor, e.g., the tryptophan operon.

Point mutation

A change in a single nucleotide, which can be silent, missense, or nonsense.

Silent mutation

A point mutation that does not change the amino acid sequence of a protein.

Missense mutation

A point mutation that changes one amino acid in a protein.

Nonsense mutation

A point mutation that creates a premature stop codon in a protein.

Frameshift deletion

A mutation caused by the removal of nucleotides, shifting the reading frame of the mRNA.

Frameshift insertion

A mutation caused by the addition of nucleotides, altering the reading frame.

Thymine dimer

A type of DNA damage caused by UV light, leading to the covalent bonding of adjacent thymine bases.

Chemical mutation

A change in DNA sequence caused by exposure to certain chemicals that alter base pairs.

DNA repair mechanisms

Processes by which cells correct mutations in their DNA, such as nucleotide excision repair.

Selection for mutant bacteria

Methods used to isolate and grow bacteria that have specific mutations.

Tryptophan auxotroph

A strain of bacteria that cannot synthesize tryptophan and must obtain it from the environment.

Ames test

A test to determine the mutagenic potential of a compound by observing mutations in bacteria.

Transformation

The process by which bacteria take up extracellular DNA from their environment.

Transduction

The transfer of bacterial DNA via bacteriophages (viruses that infect bacteria).

Conjugation

The direct transfer of DNA between two bacteria through physical contact.

F+ cell

A bacterial cell with a fertility factor that allows it to transfer DNA to others.

HFR cell

A high-frequency recombinant cell that can transfer chromosomal DNA to a recipient during conjugation.

Recombinant cell

A cell that contains DNA from two different sources, resulting from processes like conjugation.