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Pmcol 200 > L22 > Flashcards

L22 Flashcards

1
Q

Antibiotics

A

soluble compounds that are produced and released by microorganisms and that inhibit the growth or kill other microorganisms.

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2
Q

Narrow definition of antibiotics expanded to include

A

Synthetically or semi-synthetically produced antimicrobial agents

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3
Q

Bacteria

  • cell type
  • when did they appear on earth
  • habitat
  • relationships with plants
A
  • single cell
  • first life form
  • most habitats (soil, water, acidic hot springs, within earth’s crust)
  • symbiotic and parasitic relationship with plants
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4
Q

Classification of bacteria (3)

A
  1. aerobic versus anaerobic
  2. Shapes (rod, spheres, or spirals)
  3. Cell wall components (gram negative or gram positive)
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5
Q

feature is used to classify bacteria into gram-positive

bacteria and gram-negative bacteria.

A

2 types of cell wall

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6
Q

Bacterial cell walls are made of

A

polysaccharide chains called peptidoglycan

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7
Q

G+ and g- cell wall

Most bacteria have which type of cell wall

A

Gram-positive bacteria possess a thick cell wall with many layers of peptidoglycan.
• Gram-negative bacteria have a relatively thin cell wall with few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins
• Most bacteria have the gram-negative cell wall

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8
Q

Peptidoglycan consists of

Contributes to overall __ and __ of bacteria

A

glycan strands made of alternating N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) residues cross-linked by peptides

Structure, shape

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9
Q
  • individual strands of peptidoglycan are polymerized by enzyme _______ (GT) into peptidoglycan chain
  • ______ (TP) cross link the strands.

What is targeted by many antibiotics (penicillin binding protein)

A
  • individual strands are polymerized by enzyme glycosyltransferase (GT) into peptidoglycan chain
  • Transpeptidase (TP) cross link the strands.

TP is targeted by many antibiotics (penicillin binding protein)

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10
Q

We are covered in thousands of microbial species called

A

normal flora

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11
Q

Normal flora only cause trouble if immune
systems are___ or if they gain access to normally___ part of the body (ie bowel
perforation).

A

weekend

sterile

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12
Q

Pathogens do/do not require that the host be

immunocompromised or injured.

A

do not

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13
Q

•Prior to____ in
the 1930s and____ in
the 1940s,

A

sulfonamides

penicillins

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14
Q

“spectrum of activity” – can be___ or__ spectrum depending on the
number of different bacterial species against which they exhibit useful activity.

A

narrow

broad

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15
Q

“bacterial sensitivity” - sensitivity is measured by assessing the ability of bacterial strain to___ following antibiotic exposure.___ antibiotic leads to
permanent loss of replicative ability.____ antibiotic leads to temporary
loss of growth and replication that returns following the removal of antibiotics.

A

replicate
Bacteriocidal
Bacteriostatic

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16
Q

“Therapeutic index” - ratio of the __ __likely to produce an

adverse effect to the minimum concentration needed to produce a __ __

A

minimum concentration

desired effect.

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17
Q

“Ability to penetrate”

A

delivery of antibiotic to site of infection

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18
Q

1st commercially developed Ab
discovered by
product of fungus

A

penicillin
Alexander flemming
P/ notatun

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19
Q

___ derived from fungus ____ in ___

A

cephalosporins
acremonium
1945

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20
Q

•Penicillins and cephalosporins are called “__ __” because they have an unusual 4 member
ring

A

beta lactams

21
Q

cell wall inhibitors •inhibit cell wall synthesis by inhibiting an enzyme (___) responsible for ___ components of the cell wall (bacterio____)

A

DD-transpeptidase
cross-linking
bacteriocidal

22
Q

•DD transpeptidase is also called

A

penicillin binding

protein

23
Q

cell wall inhibitors orginally
only effective against ____bacteria, but successive generations of_____ have increased activity against gram negative bacteria (though still work better on gram positive bacteria)

A

gram positive bacteria

cephalosporins

24
Q 
Beta-lactamases
are bacterial enzymes
(penicillinases, cephalosporinases)
made by most\_\_\_ and many
gram\_\_\_\_ organisms that hydrolyze
the \_\_\_\_ ring of certain penicillins
and cephalosporins; confer resistance.
A

staphylococci
negative
beta-lactam

25
Q 
Beta-lactamase inhibitors (i.e.
\_\_ \_\_) are potent inhibitors of
\_\_\_\_ used in combinations
to protect hydrolyzable penicillins from
inactivation
A

calvulanic acid

beta-lactamases

26
Q

vancomycin is not a ___, but also inhibits peptidoglycan __ __

produced in nature by __ species, __ __,
commonly found in soil

A

vancomycin is not a beta-lactam, but also inhibits peptidoglycan cross linking

produced in nature by Actinobacteria species, Amycolatopsis orientalis,
commonly found in soil

27
Q

•Bacteria use folic acid to synthesize __ __that make up their DNA

A

nucleic acid

28
Q

Para-aminobenzoic acid (PABA) is a

A

nutrient obtained from the environment

precursor for folate in bacteria

29
Q

• eukaryotes also use folic acid to build

nucleic acid, but can pull from ___

A

environment (food)

30
Q

Sulfonamides and trimethoprim
resemble__ and dihydrofolic acid, respectively, and__ with PABA metabolic pathways

•Usually __ __ to block sequential
steps in synthesis of folic acid

A

PABA
interfere

given together

31
Q

•Bacteria make protein from mRNA
template within the bacterial __
ribosomal complex

A

70s

32
Q

•__(t6) transfers an amino acid to the growing

amino acid chain (__)

A

tRNA

transpeptidation

33
Q

•eukaryotes have an 80s ribosomal
complex (__and__ subunits), so__ by protein synthesis
inhibitors

A

60S
40S
unaffected

34
Q

Chloramphenicol and Macrolides (M) bind to the__ subunit and block__

A

50S

transpeptidation

35
Q

__ bind to the 30s subunit and prevent__ of incoming__

A

Tetracyclines binding

tRNA

36
Q 
aminoglycosides bind the\_\_ ribosomal subunit
1.Block the\_\_ of the
complex
2.cause\_\_ of the
code on the\_\_ template
3.inhibit\_\_
A

30s

initiation
misreading, mRNA
translocation

37
Q

•Why don’t antibiotics inhibit protein

synthesis in human cells as well?

A

Selectivity
differences in protein synthesis enzymes between
humans and microorganisms, and the
rapid growth of bacteria

38
Q 
Chloramphenicol specifically does not bind to the\_\_ ribosomal RNA of
mammalian cells (only the bacterial \_\_ ribosomal subunit)
A

80S

70S

39
Q

mammalian cells cannot
synthesize folic acid from__ (must
get it from diet)

A

PABA

40
Q

resistance is the

A

ability of
the microbe to resist the
effects of antibiotics

41
Q

Bacterial resistance:
1.Drug inactivation or modification
eg

A

beta lactamases are enzymes produced by

bacteria that inactivate antibiotics)

42
Q

Bacterial resistance:

2.Alteration of binding site

A

(alteration of penicillin binding proteins in

methicillin resistant staphylococcus (MRSA))

43
Q

Bacterial resistance:

3.Alteration of metabolic pathways

A

(sulfonamide resistant bacteria begin to use pre-

formed folic acid from the environment rather than making it from PABA)

44
Q

Bacterial resistance:

4.Reduced drug accumulation

A

(develop efflux pumps to actively remove antibiotic

from bacterial cell)

45
Q

•Antibiotic therapy alters the bacterial__ of the body

A

environment

46
Q

•Loss of normal intestinal flora produces__ or __ with a number of antibiotics.

A

diarrhea, GI discomfort

47
Q

•Probiotic products, including active culture yogurt, may be used as __ __ to minimize GI effects

A

adjunctive therapy

48
Q

•Many antibiotics should be accompanied by__ because sunscreens
can prevent adverse skin reactions.

A

photoprotection

49
Q 
Stevens-Johnson syndrome and toxic
epidermal necrolysis are rare conditions
in which the skin becomes\_\_
from the underlying tissue and sloughs
off the body.
A

detached

Pmcol 200 (12 decks)

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