Skip to main content
Back

Competitive Inhibitors of Metabolic Pathways quiz

Control buttons has been changed to "navigation" mode.
1/15
  • What metabolic pathway do sulfa drugs and trimethoprim target in bacteria?
    They target the folic acid synthesis pathway, which is essential for DNA and RNA nucleotide production in bacteria.
  • How do humans obtain folic acid compared to bacteria?
    Humans obtain folic acid (vitamin B9) from their diet, while bacteria synthesize it themselves.
  • What is the starting molecule for bacterial folic acid synthesis?
    The starting molecule is PABA (para-aminobenzoic acid).
  • Which enzyme do sulfonamides (sulfa drugs) competitively inhibit?
    Sulfa drugs competitively inhibit enzyme A, which converts PABA into dihydrofolic acid.
  • Why are sulfa drugs considered selectively toxic to bacteria?
    They are selectively toxic because humans do not have the enzymes for folic acid synthesis, so only bacteria are affected.
  • What is the role of tetrahydrofolic acid in bacterial cells?
    Tetrahydrofolic acid is used to build DNA and RNA nucleotides in bacterial cells.
  • How does trimethoprim inhibit bacterial folic acid synthesis?
    Trimethoprim competitively inhibits enzyme B, blocking the conversion of dihydrofolic acid to tetrahydrofolic acid.
  • Is trimethoprim a sulfa drug?
    No, trimethoprim is not a sulfa drug; it is a different type of drug that affects the same pathway.
  • What is the effect of using sulfa drugs and trimethoprim together?
    They work synergistically, meaning they are much more effective together than alone at inhibiting folic acid synthesis.
  • What is a common drug combination of a sulfa drug and trimethoprim?
    Sulfamethoxazole and trimethoprim, sold under the brand name Bactrim, is a common combination.
  • How does the combination of sulfa drugs and trimethoprim help reduce the spread of resistance?
    It reduces resistance spread because bacteria would need to develop resistance to both drugs simultaneously, which is less likely.
  • What types of bacteria are affected by sulfa drugs and trimethoprim?
    They are broad-spectrum drugs, effective against both gram-positive and gram-negative bacteria.
  • Why can't humans be harmed by drugs that inhibit bacterial folic acid synthesis?
    Humans are not harmed because they do not synthesize folic acid and lack the targeted enzymes.
  • What happens to bacterial cells if tetrahydrofolic acid is not produced?
    They cannot make DNA and RNA nucleotides, which is fatal for the cell.
  • For what type of infection are sulfa drugs still commonly used today?
    They are still commonly used to treat urinary tract infections (UTIs) and some other infections.