10.2 Antibiotics Flashcards
What is an antibiotic?
chemicals that kill or inhibit the growth of bacteria (not viruses) used to treat bacterial infections
Does not harm the cell of the infected organism
Where do antibiotics come from?
often derived from other living things like soil and fungi
Bactericidal
kill bacteria
Bacteriostatic
inhibit bacterial growth
How do antibiotics work?
inhibit bacterial cell wall synthesis
inhibit specific membrane protein/glycoprotein
–> black binding to cells
block specific enzyme action
inhibit protein synthesis and nucleic acid synthesis
bacterial cell wall is made of?
peptidoglycan
When bacteria cells grow, it secretes
autolysins
What do autolysins do?
make tiny holes to allow the cell wall to stretch
the bacterial cells need reinforcements after they make holes ___ enzyme form ___ ___ between peptidoglycan chains
peptidase
cross links
In the presence of penicillin (4)
penicillin inhibits peptidase enzyme
stops the formation of cross-links between peptidoglycan polymers in the cell wall
autolysins make tiny holes to allow the cell wall to stretch
new peptidoglycans form but cannot link up
What happens to the bacterial cell after penicillin (3)
cell wall is weaker
unable to withstand turgor pressure
water moves in by osmosis, bacteria lyses and dies
When is penicillin only effective?
When bacteria is growing
Why antibiotics do not affect viruses (5)
do not have peptidoglycan cell wall
do not have their own metabolism –> rely on host cells
no cell structures
less sites for antibiotic to act on
viruses live INSIDE host cells out of reach of antibiotics
