Week 4 Flashcards
(13 cards)
What is the role of enzymes in bacterial metabolism?
catalyze reactions that are essential for metabolic pathways, such as the glycolytic pathway, which involves various enzymatic reactions to break down glucose for energy.
What is a competitive inhibitor?
a molecule that resembles the substrate of an enzyme and competes for the enzyme’s active site, preventing the enzyme from catalyzing its normal reaction.
How does sulfanilamide act as a competitive inhibitor?
Sulfanilamide mimics PABA (para-aminobenzoic acid), which is used by bacteria to make folic acid, inhibiting the enzyme that synthesizes folic acid, which is necessary for DNA production.
What is noncompetitive (allosteric) inhibition?
Noncompetitive inhibition occurs when an inhibitor binds to an enzyme at a site other than the active site (called the allosteric site), changing the enzyme’s shape and making it unable to bind to its substrate.
What are the steps involved in DNA replication in bacteria?
DNA strands separate at the replication forks.
DNA polymerase adds nucleotides to the 3’ end of the strand.
One strand is continuous, while the other is fragmented into Okazaki fragments.
What is the role of DNA gyrase in bacterial DNA replication?
Helps uncoil and relax the DNA strand ahead of the replication fork, enabling the DNA polymerase to replicate the DNA efficiently.
How do quinolones like ciprofloxacin inhibit bacterial DNA replication?
Inhibit DNA gyrase, preventing the enzyme from unwinding DNA, which halts DNA replication and leads to cell death.
What is the selective toxicity of quinolones?
Quinolones specifically target DNA gyrase in bacteria, which is different from the topoisomerase in humans, allowing the drug to kill bacterial cells without affecting human cells.
What is the process of transcription in bacteria?
RNA polymerase reads the DNA template to synthesize a complementary mRNA strand, which carries the genetic information from DNA to the ribosome for translation.
How does rifampin inhibit bacterial transcription?
Rifampin binds to RNA polymerase, blocking the enzyme from synthesizing RNA, preventing transcription and bacterial growth.
What is the mechanism of action of Pseudouridimycin (PUM)?
targets the active site of bacterial RNA polymerase, inhibiting its activity and preventing RNA synthesis, with a lower likelihood of resistance development compared to rifampin.
What is the process of translation in bacteria?
mRNA is read by ribosomes, and tRNA brings amino acids to the ribosome to form a polypeptide chain, which folds into a functional protein.
How do antibiotics like tetracyclines and erythromycin target bacterial translation?
Tetracyclines bind to the 30S subunit of bacterial ribosomes, preventing mRNA reading
erythromycin binds to the 50S subunit, blocking polypeptide chain formation.
