Week 1.3 Flashcards
How do bacteria with and without the trait of antibiotic resistant are different on the molecular level?
Genetics:Resistant bacteria have specific resistance genes; non-resistant bacteria don’t.
Proteins:Resistant bacteria produce proteins that neutralize or evade antibiotics; non-resistant bacteria can’t.
Processes:Resistant bacteria modify processes to survive antibiotics; non-resistant bacteria are vulnerable.
Gene Transfer:Resistant bacteria can spread resistance genes; non-resistant bacteria lack this unless they acquire it.
Where do Antibiotic Resistant Bacteria come from?
Natural selection from applied selective pressure. Aka Evolution
What was the first drug used for treating tuberculosis?
Rifampicin
How does Rifampicin work?
It works by binding to RNA polymerase
How do mutant proteins help bacteria survive in the presence of antibiotics?
Mutant proteins help bacteria survive antibiotics by altering the way the bacteria interact with the drug. These mutations can:
- Modify the Antibiotic Target:Mutant proteins may change the structure of the target that the antibiotic binds to, making it harder or impossible for the drug to attach and work effectively.
- Increase Efflux:Some mutations enhance the function of efflux pumps, which actively expel the antibiotic out of the bacterial cell, reducing its concentration to non-lethal levels.
- Degrade or Modify Antibiotics:Mutant enzymes may evolve to break down or chemically modify the antibiotic, rendering it inactive.
- Bypass Inhibited Pathways:Mutations can lead to alternative pathways that bypass the blocked or inhibited processes targeted by antibiotics, allowing the bacteria to continue essential functions despite the drug’s presence.
These mutations help bacteria survive by directly counteracting the antibiotic’s mechanism of action.
What causes antibiotic resistance?
A) No cell wall
B) No cell membrane
C) Altered protein
D) being stronger
E) shaving more proteins
F) Having no proteins
Answer C, Alters a Protein’s structure.
How does the bacteria PBP2a have resistance to antibiotics?
It binds weakly to betalactam antibiotics (red), so it can cross link the peptidoglycan chains in the presence of antibiotics.
How does the bacteria VanA evolve resistance to antibiotics?
VanA builds the new type of building block that does not bind vancomycin.
What do cells use to regulate the genes involved in resistance, so that the proteins are made only when needed.
Repressor Proteins
What regulates the gene that encodes PBP2a?
The Mecl Repressor
How does the bacteria Beta-lactamases evolve resistance to antibiotics?
It breaks the reactive beta-lactam ring, inactivating the antibiotics.
How does the bacteria VanX evolve resistance to antibiotics?
It breaks down any of the original buildings blocks.
How does the bacteria Sav1866 evolve resistance to antibiotics?
It used a scissor like motion to transport antibiotics across the cell membrane.
How does the bacteria TetM evolve resistance to antibiotics?
It displaces the macrolide erythromycin, restoring the ribosome to its normal function.
What do Macrolides and Aminoglycosides attack and what does it do?
They attack ribosomes, blocking manufacture of new proteins.
