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Bio 251 > LAB 7 > Flashcards

LAB 7 Flashcards

1
Q

Non-ionizing, short-wavelength high-energy radiation

A

Ultraviolet (UV)

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2
Q

What are the 3 types of UV radiation

A

UV-A longest wavelength

UV-B 280-315

UV-C 100-280

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3
Q

molecular lesions

DNA strand is physically kinked and polymerases cannot replicate DNA resulting in cell death

A

Pyrimidine dimers

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4
Q

SOS system

A

activates when major DNA damage occurs

Will remove pyrimidine dimers and insert new pyrimidine molecules to restore the original state of DNA strand

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5
Q

chemical metabolites produced by some fungi and bacteria to kill or stop the growth of nearby competitors

*first one penicillium mold discovered by alexander fleming

A

natural antibiotics

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6
Q

are those produced chemically in the lab keeping active moiety intact but modifying the R (Sidechain) group

A

Semi-synthetic antibiotics

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7
Q

Antibiotics that target single groups

A

Narrow spectrum

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8
Q

are those that are entirely produced inside laboratories

Sulfonamides

A

Synthetic antibiotics

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9
Q

antibiotics kill bacteria

A

Bactericidal

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10
Q

antibiotics only inhibit growth but does not actually kill bacterial cells

Work in combo with your immune system to eliminate an infectious disease

A

bacteriostatic

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11
Q

What are 2 narrow-spectrum antibiotics?

A
  1. Vancomycin - active against gram + only
  2. Polymyxin B - active against gram - only
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12
Q

Antibiotics that target both gram types of bacteria

*disadvantage - remove normal microbiota, which could result in a superinfection

A

Broad-spectrum antibiotics

*tetracycline - targets gram + and - plus rickettesias and chlamydias

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13
Q

Superinfection

A

2nd infection that occurs immediately after 1st infection, usually by different pathogens

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14
Q

High selective toxicity

A

means that the drug targets bacteria and not human

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15
Q

Low selective toxicity

A

can cause more serious side effects in humans

*polymyxin B - use external only

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16
Q

Kirby-Bauer method

A

The test used to determine in vitro sensitivity of a particular bacteria to various antibiotics

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17
Q

Variables for the Kirby-Bauer method include

A
  1. Mueller-hinton II agar
  2. pH 7.2-7.4
  3. Agar thickness of 4mm
  4. Bacteria growth in liquid broth to the density of standard 10-7 bacterial cell/milliliter
    *bacterial lawn
  5. Disks impregnated with a known concentrations of antibiotics are applied
  6. Incubate plate at 37 c for 16-18 hours
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18
Q

Zone of inhibition

A

the area around the disk in which no bacteria grow

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19
Q

quantitative technique for determining antimicrobial susceptibility

The predefined gradient of antibiotic concentrations on a plastic strip

Where it crosses on the strip is telling me the min concentration needed for antibiotics concentration

A

E- Test

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20
Q

Vertical transmission

A

when genetic info is passed from parent cell to daughter cells as a result of binary fission

21
Q

Horizontal gene transfer

A

when genetic info is passed between unrelated cells.

This includes conjugation, transformation, transduction, and transposons

22
Q

Plasmids

A

Small, circular, double-stranded DNA molecules that use exist outside of bacterial chromosome

23
Q

Conjugation

A

process of transferring genetic info from donor cell to recipient cell through sexual pilis

24
Q

Antibiotic resistance genes

A

genes plasmids carry to help cell in selective environments

25
Recombinant cell
a recipient cell that has received a plasmid from a donor cell and is now an F+ cell
26
27
What is an example of a broad-spectrum antibiotic?
Tetracycline Works on both gram-positive and negative
28
What are some pathways antibiotics work
1. Inhibiting cell wall synthesis - penicillin 2. target protein synthesis 3. disruption of cell membrane - Polymyxin B 4. Inhibit DNA and RNA synthesis - ciprofloxacin & rifampicins
29
What is the advantage of Broad-spectrum and Narrow spectrum antibiotics
**Broad** - Advantage: inhibiting many types of bacteria when the infection is unknown Disadvantage: removing normal microbiota, particularly in the colon = superinfection **Narrow**- Advantage: Target single groups Disadvantage: only target single groups
30
31
A test that determines the lowest concentration that inhibits the growth of the organism
MIC Minimum Inhibitory Concentration
32
What wavelength is most damaging and lethal
33
Chemical metabolites produced naturally by some fungi and bacteria
Antibiotics
34
What was the first antibiotic used commercially
Penicillin dervied from *penicillium*
35
36
What test is used to determine the invitro sensitive pattern of a particular bacterium to various antibiotics and shows the zone of inhibition?
Kirby Bauer method
37
What are some factors that could influence the size of the zone of inhibition for an antibiotic?
Agar thickness drug concentration pH
38
What antibiotic test is essential for patients who have liver or kidney disorders which prevent metabolizing the antibiotic, requiring the smallest amount to be used?
E-test
39
What measurement is read here?
MIC
40
What value is read here and what kind of antibiotic would it be?
Bacteriocidal
41
What value is read here and what kind of antibiotic would it be?
bacteriostatic
42
What does Minimum inhibitory concentration mean?
Lowest concentration that inhibits the growth of the organism
43
Which UV has the most damaging wave lengths? What is the number wave length that is most damaging?
UV C 260 nm
44
UV wave lengths at 254-260nm result in DNA damage by
45
What are some factors that are important in the lethal effects of UV light?
time of exposure distance from UV light barriers
46
Which is more resistant to UV light? S. epidermidis or B. cereus?
B. cereus
47
If a cell is starved for nutrients would you think they are more or less susceptible to UV effects?
More, it overwhelms their repair system
48
Explain why UV light exposure results in skin cancer and not liver or lung
Because it cannot get into liver or lung
49
Why is conjugation important in a healthcare setting?
provides, for instance, a platform for the spread and persistence of antibiotic resistance genes

Bio 251 (17 decks)

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