Transcription, Translation, and Antibiotic Resistance Flashcards

Vocabulary flashcards covering bacterial transcription, translation, ribosomal function, and mechanisms of rifampin and tetracycline action and resistance.

Rifampin

An antibiotic that blocks RNA synthesis (transcription) by binding to a pocket in the mRNA exit channel of RNA polymerase.

Tetracycline

An antibiotic that blocks protein synthesis (translation) by binding to the attachment site (A site) of the ribosome and preventing tRNA entry.

Nucleotide

The monomer building block of nucleic acids, consisting of a phosphate group, a five-carbon sugar (ribose or deoxyribose), and a nitrogenous base.

Purines

A class of nitrogenous bases characterized by a two-ring structure, comprising adenine and guanine.

Pyrimidines

A class of nitrogenous bases characterized by a single-ring structure, comprising cytosine, thymine, and uracil.

Gene

A segment of DNA that is transcribed into a functional RNA molecule.

Messenger RNA (mRNA)

The coding type of single-stranded RNA transcribed from DNA that carries genetic information to the ribosome for translation into protein.

Transfer RNA (tRNA)

A specialized RNA carrier molecule containing an anticodon on one end that delivers specific amino acids to the ribosome during translation.

Ribosomal RNA (rRNA)

The catalytic RNA components of the ribosome that perform the enzymatic work of peptide bond formation during protein synthesis.

Promoter

A specific sequence of DNA upstream of a gene where RNA polymerase binds to initiate transcription.

Sigma Factor

A specialized bacterial protein that binds to the promoter sequence on DNA to assist RNA polymerase in attaching and starting transcription.

Rho-Dependent Termination

A transcription termination mechanism in which the Rho protein tracks behind RNA polymerase, recognizes a specific DNA sequence, and causes the enzyme to detach.

Rho-Independent Termination

A transcription termination mechanism where complementary base pairing in newly synthesized RNA forms a hairpin loop inside RNA polymerase, causing it to swell and pop off DNA.

A Site (Attachment Site)

The ribosomal binding pocket where incoming tRNA carrying an amino acid first attaches by matching its anticodon to the mRNA codon.

P Site (Polymerization Site)

The central ribosomal pocket where the tRNA holds the growing peptide chain and polymerizes new amino acids onto it.

E Site (Exit Site)

The final ribosomal pocket where uncharged tRNA is shifted prior to being released back into the cell.

Codon

A sequence of three adjacent nucleotides on mRNA that specifies a single amino acid or translation stop signal.

Start Codon

The specific triplet code AUG on mRNA that marks the initiation point of translation and codes for methionine.

Wobble Effect

The flexibility at the third nucleotide position of a codon that allows multiple codon variations to specify the same amino acid.

TetO Protein

A target-modification protein that binds to tetracycline-blocked ribosomes, alters ribosomal conformation to dislodge tetracycline, and restores translation.

rpoB Gene

The bacterial gene encoding the subunit of RNA polymerase containing the rifampin binding pocket, in which point mutations lead to antibiotic resistance.