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Pharmacology III > Exam 3 Tim > Flashcards

Exam 3 Tim Flashcards

1
Q

Classification of antibiotics based on (3)

A
  • class and spectrum (gram + vs - vs both)
  • biochemical pathway it interferes with
  • chemical structure of the pharmacophere
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2
Q

general steps of peptidoglycan biosynthesis (3)

A
  • (in cytoplasm) sugar –> lipid –> lipid I –> lipid II
  • translocation of lipid II from cytoplasm to periplasm
  • (in periplasm) lipid II polymerization, PG-cross linking, lipid recycle
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3
Q

Beta-lactams inhibit what step of peptidoglycan synthesis

A
  • TPase step
  • trans peptidase inhibition
  • trans peptidation/crosslinking step
  • comes after transglycosylation
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4
Q

glycopeptides inhibit what step of peptidoglycan synthesis

A
  • TGase step
  • trans glycosylation inhibition
  • ONLY WORK ON GRAM + (too large)
  • work by forming complexes with uncrosslinked peptide (on D-ala-D-ala) strands –> block transglycosylation
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5
Q

Transpeptidases are

A
  • active site serine hydrolases
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6
Q

Penicillin binding protein

A
  • anything (protein) that binds penicillin
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7
Q

Penicillin acts as a _____ unless attack of _____

A
  • irreversible suicide inhibitor of TPase

- unless attack of water

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8
Q

Unique characteristics of 5th generation cephalosporin and name

A
  • 5th gen: unique aspects, broad spectrum, both bind to PBP-2a, which is responsible for resistance to methicillin (MRSA)
  • ceftaroline
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9
Q

PBP-2a

A
  • PBP on staph aureus responsible for MRSA

- bifunctional transpeptidase/ transglycosylase

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10
Q

1-4th gen of cephalosporin

A
  • lead to diff penetration through porins (G (-))
  • varied antibacterial and pharmacokinetic properties
  • hypersensitivity most common adverse
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11
Q

five gens of penicillin

A
  • vary on narrow vs broad spectrum/ whether antipseudomonal (gram -) activity
  • hypersensitivity most common adverse
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12
Q

Which drug treats TB that was featured?

A
  • Isonazid
  • used in combo with other drugs for treatment (usually 4)
  • as monotherapy for latent TB
  • less freq used as comination regimen for nonTB mycobacterial infections
  • MOA: acts as mimic of nicotinamide.. complex, isoniazid-NAD adduct inhibits INHa, best defined mech is inhibitor of mycolic acid biosynthesis (greasy outside layer)
    Adverse: low in general, peripheral neuropathy and CNS toxicity
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13
Q

Tetracyclines and glycylcyclines

A
  • tigecycline
  • A site 30S
  • block incoming aminoacyl TRNA
  • adverse: GI irritation, photosensitivity, discoloration of teeth
  • bacteriostatic
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14
Q

Tigecycline

A
  • tetracycline resistant to efflux
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15
Q

Aminoglycosides

A
  • Gentamicin C
  • A site 30S
  • interfere with initiation
  • primarily used gram (-), widely used b/c of BACTERICIDAL action and synergy with b-lactams
  • adverse: nephrotoxicity and ototoxicity (damage to inner ear)
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16
Q

Macrolides

A
  • arithromycin, azithromycin, clarithromycin
  • E site 50S
  • block polypeptide exit tunnel
  • bacteriostatic
17
Q

Synercid

A
  • pristinamycins
  • Qunupristin AND Dalfopristin together
  • E site 50S at places partially overlapped by macrolides
  • derived from streptogramins
18
Q

Linezolid

A
  • only totally synthetic antibiotic that blocks protein synthesis (others that are still totally synthetic)
  • binds to P site (peptidyl elongation) 50S
  • most active against Gram +
19
Q

Retapulin

A
  • analog of fungal natural product
  • topical ointment approved for treating impetigo
  • binds near P-site on 50S
20
Q

Telithromycin does not what?

A
  • induce rRNA methylation resistance gene expression
  • remember MLSb resistance phenotype
  • this is a ketolide macrolide
  • 3rd gen macrolide
21
Q

Tedizolid

A
  • second gen oxazolidinone (other drug in this category is linezolid)
  • active against linezolid resistant staphylococci
  • 10x more potent than linezolid against MRSA
22
Q

Topo II

A
  • DNA gyrase
  • introduces negative supercoils, relaxes positive supercoils
  • cuts both strands at once
23
Q

topo IV

A
  • decatenates DNA (separating the DNA of daughter chromosomes once DNA replication is completed.)
  • removes pos and neg supercoiling
24
Q

Quinolones induce the _____

A
  • accumulation of double cut covalent DNA-enzyme intermediate by preventing DNA supercoiling
25
Q

antibiotics that inhibit DNA gyrase and topo IV

A
  • quinolones

- ciprofloxacin, levofloxacin, gatifloxacin

26
Q

Quinolones

A
  • work best on gram neg but good for gram pos with new generations (THIS IS RIGHT)
  • bactericidal
  • generally well tolerated but can have CNS toxicity
  • nalidixic acid worst toxicity (first gen)
27
Q

Rifampin

A
  • inhibits RNA polymerase to block RNA synthesis to kill bacteria
  • blocks elongating RNA chain by binding DNA/RNA tunnel of b subunit (bottom jaw) of RNA pol
  • bactericidal
28
Q

Fidaxomicin

A
  • binds to switch region and inhibits RNAP
  • stays in GI where it needs to work (essentially zero systemic viability)
  • specific to C. difficile
  • bactericidal
29
Q

Rifampin and Rivapentine

A
  • both primarily used for treatment of TB
  • major problem is compliance
  • bactericidal agents
  • G (+) over Gram (-)
  • poor drug penetration
30
Q

can bacteria use exogenous tetrahydrafolate?

A
  • no
31
Q

Cotimoxazole

A
  • sulfamexothoxazole and trimethoprim

- work synergistically to inhibit both steps of tetrahydrofolate synthesis

32
Q

Sulfamethoxazole

A
  • sulfa drug
  • inhibits Dihydropteroate Synthase (not in humans) by mimicking PABA
  • competitive inhibitor
  • inhibits from GTP to Dihydropteroate
33
Q

Trimethoprim

A
  • diaminopyrimidine
  • inhibits dihydrofolate reductase
  • dihydrofolate to tetrahydrafolate
  • great selectivity for bacterial DHFR over human
34
Q

Which 3 drugs disrupt cell membranes?

A
  • Gramicidin
  • Polymyxin
  • Daptomycin (complex with Ca)
35
Q

Gramicidin and Polymyxins work on which gram and what’re they used for?

A
  • gram negative
  • interact with lipopolysaccharide on surface of G(-)
  • topical OTC ointments
36
Q

Colistin

A
  • high toxicity and used primarily for resistant gram - infections
  • disrupts cell membranes
  • last line of defense
37
Q

Daptomycin primarily active against which gram?

A
  • positive
  • lipopeptide
  • new drug, not much resistance yet
  • complexes with Ca followed by membrane disruption

Pharmacology III (18 decks)

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