antibiotics

Question 1

what percentage of known antibiotics are clinically useful?

Answer 1

less than 1%

Question 2

what antibiotics are B-lactam antibiotics?

Answer 2

penicillins, cephalosporins and cephamycins

Question 3

what fungus produces penicillin?

Answer 3

Penicillium chrysogenum

Question 4

what accounts for more than half of antibiotic production?

Answer 4

penicillins and cephalosporins

Question 5

what is the mechanism of action of B-lactam?

Answer 5

they inhibit cell wall synthesis - the transpeptidation reaction.
transpeptidases bind to the beta lactam ring, so the cell wall continues to be formed but is no longer cross linked, so it becomes weak. osmotic differences result in cell lysis

Question 6

what is the transpeptidation reaction?

Answer 6

it is essential to cell wall synthesis (cross linking).

Question 7

what contains a 6 member dihydrothiazine ring?

Answer 7

cephalosporins

Question 8

what type of antibiotics have a broad spectrum of activity?

Answer 8

cephalosporins and some penicillins

Question 9

what is cephalosporins resistant to?

Answer 9

beta lactamases

Question 10

list some aminohglycosides

Answer 10

streptomycin, kanamycin, neomycin, gentamicin

Question 11

how do aminoglycosides work?

Answer 11

they inhibit protein synthesis at the 30s subunit

Question 12

which type of bacteria do aminoglycosides work against?

Answer 12

gram negative

Question 13

what are some semi synthetic penicilins?

Answer 13

ampicillin, oxacillin, methacillin

Question 14

what do macrolides consist of?

Answer 14

large lactone rings connected to sugar

Question 15

what is an example of a macrolide?

Answer 15

erythromycin

Question 16

how do macrolides work?

Answer 16

they inhibit protein synthesis at the 50s subunit

Question 17

what is used in patients ho are allergic to penicillin?

Answer 17

macrolides

Question 18

which were the first broad spectrum of antibiotics?

Answer 18

tetracylines

Question 19

what is the basic structure of tetracylines?

Answer 19

a naphthacene ring sysytem

Question 20

how do tetracylines work?

Answer 20

interfere with the 30s ribosomal subunit function

Question 21

what area do tetracylines have a wide use in?

Answer 21

veterinary medicine

Question 22

what are growth factors?

Answer 22

specific substances required by microbes because they cannot synthesis them

Question 23

what are growth factor analogue?

Answer 23

they block the utilisation of growth factors

Question 24

what does sulfanilamide do?

Answer 24

blocks the synthesis of folic acid

Question 25

can bacteria synthesise their on folicc acid?

Answer 25

yes, but eukaryotes obtain it from their diets

Question 26

what is isoniazid?

Answer 26

a gorwth factor analogue effective against mycobacterium only, it interferes with the synthesis of mycolic acid

Question 27

how are nucelic acid base analogues have been formede?

Answer 27

by the addition of bromine or fluorine

Question 28

what are quinolones?

Answer 28

antibacterial compounds that interfere with dna gyrase, eg ciproflaxcin

Question 29

what do antiviral drugs do?

Answer 29

target host structures

Question 30

which are the most succesful and commonly used antivirals?

Answer 30

nuceloide analogues

Question 31

what do Nonnucleoside reverse transcriptase inhibitors (NNRTI) do?

Answer 31

bind directly to RT and inhibit reverse transcription

Question 32

what do protease inhibitors do?

Answer 32

inhibit the processing of large viral proteins into individual components

Question 33

what do fusion minhibitors do?

Answer 33

prevent viruses from successfully fusing with the host cell

Question 34

which categories of drugs sucessfully limit influenza infection?

Answer 34

Adamantanes

Neuraminidase inhibiors

Question 35

what are interferons?

Answer 35

small proteins that prevent viral multiplication by stimulating antiviral proteins in uninfected cells

Question 36

why do fungi pose special problems for chemotherapy?

Answer 36

bc theyre eukaryotic, so alot of their cellular machinery is the same as animals and humans, so we are limited with the targets we can have. hence why many antifungals are topical, A few drugs target unique metabolic processes unique to fungi

Question 37

give some examples of antifungal drugs, say what they target

Answer 37

• ergosterol inhibitors - they target ergosterol
• echinocandins inhibits part of the cell all, specifically used to treat Candida infections
• Other drugs target chitin biosynthesis, folate biosynthesis, or disrupt microtubule aggregation