Lecture Exam 3 Flashcards
Antibiotics
Antimicrobial agent that kills and interferes with the growth of microbes
Synthetic antibiotic
Not natural: made in the lab
Semi synthetic antibiotics
Natural product that is modified in the lab
Why was cantaloupe used to produce penicillin
It is cheep and easy to grow
- makes lots
Broad spectrum
Antibiotic works against many types of bacteria
Narrow spectrum
Antibiotic works only on a certain bacteria
Specific!!
Superinfection
Bacterial overgrowth
What causes a superinfection?
Disruption of a community
- overgrowth of a certain microbe
Magic bullet idea
Kill the bacteria w/o harking host cells
What is the technical term for “magic bullet”
Selective toxicity
Antimicrobial drugs
Kill or interfere with growth of microbes
Bacteriostatic
Reversibly stops bacteria from growing
- “static” like the tv is stuck
Bactericidal
Kills bacteria
- like suicide - kill oneself
What are the 5 mechanisms of action for Antimicrobial drugs ( inhibit what)
- Inhibit cell wall synthesis
- Inhibit protein synthesis (ribosome)
- Inhibit dna replication
- Injury the plasma membrane
- Inhibit metabolism
Transpeptidase
Enzyme that joins cross bridges on the cell wall
Penicillin
beta lactam ring = consistent part
Side chain = what makes them different (variable)
Competitive inhibitor
It competes w/ substrate to bind to active site
- able to bind to active site making it still a functional enzyme
Non competitive inhibitor
Binds outside of substrate- substrate still able to bind to active site
- makes it nonfunctional due to changing shape
Penicillin is a _______ inhibitor
Competitive
How does penicillin inhibit cell wall synthesis?
It inactivated transpeptidase, weakening the cell wall - resulting in the cell lyses (die)
What type of solution would the cell lyse in the presence of penicillin?
Hypotonic
Penicillinase
Breaks the beta-lactam ring of penicillin making the antibiotic not functional
What are the beta lactams we looked at?
- natural penicillin
Methicillin
Amoxicillin
Penicillin is most effective against
Gram positive : due to having difficult time getting through outer membrane of gram negative