L22

Question 1

Antibiotics

Answer 1

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

Question 2

Narrow definition of antibiotics expanded to include

Answer 2

Synthetically or semi-synthetically produced antimicrobial agents

Question 3

Bacteria

• cell type
• when did they appear on earth
• habitat
• relationships with plants

Answer 3

• single cell
• first life form
• most habitats (soil, water, acidic hot springs, within earth’s crust)
• symbiotic and parasitic relationship with plants

Question 4

Classification of bacteria (3)

Answer 4

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

Question 5

feature is used to classify bacteria into gram-positive

bacteria and gram-negative bacteria.

Answer 5

2 types of cell wall

Question 6

Bacterial cell walls are made of

Answer 6

polysaccharide chains called peptidoglycan

Question 7

G+ and g- cell wall

Most bacteria have which type of cell wall

Answer 7

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

Question 8

Peptidoglycan consists of

Contributes to overall __ and __ of bacteria

Answer 8

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

Structure, shape

Question 9

• 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)

Answer 9

• 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)

Question 10

We are covered in thousands of microbial species called

Answer 10

normal flora

Question 11

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

Answer 11

weekend

sterile

Question 12

Pathogens do/do not require that the host be

immunocompromised or injured.

Answer 12

do not

Question 13

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

Answer 13

sulfonamides

penicillins

Question 14

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

Answer 14

narrow

broad

Question 15

“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.

Answer 15

replicate
Bacteriocidal
Bacteriostatic

Question 16

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

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

Answer 16

minimum concentration

desired effect.

Question 17

“Ability to penetrate”

Answer 17

delivery of antibiotic to site of infection

Question 18

1st commercially developed Ab
discovered by
product of fungus

Answer 18

penicillin
Alexander flemming
P/ notatun

Question 19

___ derived from fungus ____ in ___

Answer 19

cephalosporins
acremonium
1945

Question 20

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

Answer 20

beta lactams

Question 21

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

Answer 21

DD-transpeptidase
cross-linking
bacteriocidal

Question 22

•DD transpeptidase is also called

Answer 22

penicillin binding

protein

Question 23

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)

Answer 23

gram positive bacteria

cephalosporins

Question 24

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.

Answer 24

staphylococci
negative
beta-lactam

Question 25

``` Beta-lactamase inhibitors (i.e. __ __) are potent inhibitors of ____ used in combinations to protect hydrolyzable penicillins from inactivation ```

Answer 25

calvulanic acid | beta-lactamases

Question 26

vancomycin is not a ___, but also inhibits peptidoglycan __ __ produced in nature by __ species, __ __, commonly found in soil

Answer 26

vancomycin is not a beta-lactam, but also inhibits peptidoglycan cross linking produced in nature by Actinobacteria species, Amycolatopsis orientalis, commonly found in soil

Question 27

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

Answer 27

nucleic acid

Question 28

Para-aminobenzoic acid (PABA) is a

Answer 28

nutrient obtained from the environment | precursor for folate in bacteria

Question 29

• eukaryotes also use folic acid to build | nucleic acid, but can pull from ___

Answer 29

environment (food)

Question 30

Sulfonamides and trimethoprim resemble__ and dihydrofolic acid, respectively, and__ with PABA metabolic pathways •Usually __ __ to block sequential steps in synthesis of folic acid

Answer 30

PABA interfere given together

Question 31

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

Answer 31

70s

Question 32

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

Answer 32

tRNA | transpeptidation

Question 33

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

Answer 33

60S 40S unaffected

Question 34

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

Answer 34

50S | transpeptidation

Question 35

__ bind to the 30s subunit and prevent__ of incoming__

Answer 35

Tetracyclines binding | tRNA

Question 36

``` aminoglycosides bind the__ ribosomal subunit 1.Block the__ of the complex 2.cause__ of the code on the__ template 3.inhibit__ ```

Answer 36

30s initiation misreading, mRNA translocation

Question 37

•Why don’t antibiotics inhibit protein | synthesis in human cells as well?

Answer 37

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

Question 38

``` Chloramphenicol specifically does not bind to the__ ribosomal RNA of mammalian cells (only the bacterial __ ribosomal subunit) ```

Answer 38

80S | 70S

Question 39

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

Answer 39

PABA

Question 40

resistance is the

Answer 40

ability of the microbe to resist the effects of antibiotics

Question 41

Bacterial resistance: 1.Drug inactivation or modification eg

Answer 41

beta lactamases are enzymes produced by | bacteria that inactivate antibiotics)

Question 42

Bacterial resistance: | 2.Alteration of binding site

Answer 42

(alteration of penicillin binding proteins in | methicillin resistant staphylococcus (MRSA))

Question 43

Bacterial resistance: | 3.Alteration of metabolic pathways

Answer 43

(sulfonamide resistant bacteria begin to use pre- | formed folic acid from the environment rather than making it from PABA)

Question 44

Bacterial resistance: | 4.Reduced drug accumulation

Answer 44

(develop efflux pumps to actively remove antibiotic | from bacterial cell)

Question 45

•Antibiotic therapy alters the bacterial__ of the body

Answer 45

environment

Question 46

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

Answer 46

diarrhea, GI discomfort

Question 47

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

Answer 47

adjunctive therapy

Question 48

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

Answer 48

photoprotection

Question 49

``` Stevens-Johnson syndrome and toxic epidermal necrolysis are rare conditions in which the skin becomes__ from the underlying tissue and sloughs off the body. ```

Answer 49

detached