week 3

Question 1

binary fission

Answer 1

• asexual reproduction
• bacteria and archaea
• exponential increase in population
• replicate and segregate BEFORE dividing

Question 2

what are the phases of the bacterial growth curve?

Answer 2

lag, exponential, stationary, death, and long-term stationary

Question 3

lag phase

Answer 3

• no bacterial growth
• preps for division so like the synthesis of new components and DNA replication

Question 4

exponential phase

Answer 4

grows as quickly as possible in the conditions available

Question 5

stationary phase

Answer 5

• growth stops due to nutrients and O2 being less available

Question 6

death phase

Answer 6

exponential decrease in living cells

Question 7

long-term stationary phase

Answer 7

evolution occurs with the remaining cells

Question 8

most microbes live in what kind of an environment?

Answer 8

hypotonic

Question 9

hypotonic def

Answer 9

there is less solute outside the cell than inside and the cell wall is what keeps it that way

Question 10

take a look at the equations

Question 11

4 (+2) cardinal factors that affect bacterial growth

Answer 11

temperature, O2 concentration, pH, water activity
pressure and radiation

Question 12

5 groups of microbes in regards to temp.

Answer 12

psychrophiles: 0-20C
psychrotolerants: 0-35
mesophiles: 20-45
thermophiles: 45-85
hyperthermophiles: 85-100

Question 13

5 groups of microbes in regards to O2 conc.

Answer 13

• obligate aerobic: requires O2
• microaerophile: requires low O2
• facultative anaerobe: does not require but grows better with O2
• aerotolerant anaerobe: grows w/ or w/o O2
• strict anaerobe: killed in O2

Question 14

2 groups in regards to pH

Answer 14

acidophiles: 0-5.5
alkaliphiles: 8-11.5

Question 15

osmophiles

Answer 15

microbes that have adapted to a hypertonic environment and need high salt conc.

Question 16

2 kinds of osmophiles

Answer 16

halophiles: 0.2M
extreme halophiles: 3-6.2M

Question 17

what are biofilms?

Answer 17

it is an environment where a community of microorgs (which may be different species) come together, communicate, and thrive in favorable conditions

Question 18

biofilms have a key property that is “there is power in blank”

Answer 18

• numbers
• “stronger together”

Question 19

examples of biofilms

Answer 19

medical devices, sewege system, shipping industry and plaque on teeth

Question 20

quorum sensing

Answer 20

• cell to cell communication via autoinducers. They diffuse into the environment and send signals to other cells.
• There has to be enough microbes participating in the biofilm for it to work

Question 21

physical techniques regarding microbial growth/elimination

Answer 21

filtration, sterilization, radiation

Question 22

filtration tech.

Answer 22

removes microorgs in heat sensitive materials

Question 23

3 ways of sterilization tech.

Answer 23

• autoclave: steam
• dry heat: less effective than autoclaving, higher temp, more exposure time, does not melt glass, just plastics
• pasteurization: less temp, kills and slows spoilage but doesn’t sterilize,

Question 24

2 ways of radiation tech.

Answer 24

-UV: causes thymine dimers which prevents replication
ionization: gamma radiation dislodges the electrons creating free radicals

Question 25

chemical techniques regarding microbial growth/elimination

Answer 25

- phenolics- disinfectants (lysol) -alcohols- denatures proteins and membrane lipids - halogens- oxidizing agents (I2 or Cl2) - heavy metals- inactivate proteins (mercury, silver, zinc) - antibiotics- natural pdts that kill microbes or inhibit growth (penicillin, sulfa drugs (prontosil red), streptomycin)

Question 26

ways to count viable cells

Answer 26

- standard plate counts - counting chamber (grids) - membrane filter tech. (filtered, stained) - flow cytometry (a tube so narrow that only one cell can pass at a time)

Question 27

penicillin info

Answer 27

- fleming - has an effect on gram (+) - treats strep.

Question 28

sulfa drugs (prontosil red) info

Answer 28

- Donagsk - protect w/o toxicity - treats staph

Question 29

streptomycin

Answer 29

- Waksman - has an effect on gram (-) - treats TB

Question 30

arsenic info

Answer 30

- Erhilic - 1st chemo: poisonous but kills microbes - treats syphilis

Question 31

-cide

Answer 31

kills - MIC (inhibitory)

Question 32

-static

Answer 32

inhibits growth - MLC (lethal)

Question 33

3 ways to measure the effectiveness of the antimicrobial activity of drugs

Answer 33

- dilution: add in the MLC and MIC and see how well they work - disk- kirby bauer method: measure the diameter of the antimicrobial-ness - e-test: the strip has antibiotics on it and whenever the bacteria starts to form just correlate the number of the strip with it

Question 34

what inhibits the synthesis of the cell wall?

Answer 34

- penicilin - cephalosporins - vancomycin

Question 35

what inhibits ribosomal function/synthesis?

Answer 35

- macrolides (50S) - aminoglycosides (30S) - chloramphenicol (23S) - tetracyclines (16S)

Question 36

what inhibits metabolic pathways?

Answer 36

- sulfa drugs - trimethoprim (similar to sulfa)

Question 37

what inhibits nucleic acid synthesis?

Answer 37

- fluoroquinolones - rifamycins

Question 38

why are there limitations for drugs that are antiprotozoan and antifungal?

Answer 38

- They are eukaryotic and too similar to our cells - antip: plasmodium treats malaria and quinine

Question 39

2 types of drug resistance

Answer 39

- intrinsic- resistant due to lacking the thing that the drug targets ----ex: mycoplasma resistant to B-lactam antibiotics bc it targets the cell wall and bacterias lack a cell wall - acquired- a change happened in the genome that caused it to be resistant