Chapter 6: Microbial Growth

Question 1

What are the 5 Is to purify and characterize organisms?

Answer 1

1. Inoculation- place sample in sterile medium
2. Incubation- create proper growth environment
3. Isolation- result of inoculation and incubation
4. Inspection- observe macroscopic and microscopic characters
5. Identification- look at morphological characteristics, differential staining, biochemical tests

Question 2

What is carbon responsible for in bacterial growth?

Answer 2

-required to make structural molecules
- autotrophs use CO2 as carbon source and inorganisc salts as N source
-heterotrophs use organic carbon sources

Question 3

What is nitrogen responsible for in bacterial growth?

Answer 3

• used to make amino acids and proteins
  -comes from atmosphere but in order for heterotroph (animal) to process it, it has to be fixed by autotrophs (plants)

Question 4

What is sulfur responsible for in bacterial growth?

Answer 4

• used in amino acids, vitamins (thiamine and biotin)
• important sources of sulfur is sulfate ion, hydrogen sulfide

Question 5

What is phosphorous responsible for in bacterial growth?

Answer 5

used in DNA, RNA, ATP and membranes
- important source- phosphate ion

Question 6

What is oxygen responsible for in bacterial growth?

Answer 6

• used to distinguish between different organims

Question 7

obligate aerobe

Answer 7

needs more oxygen
obtain energy by respiration
produce SOD (superoxidative dismutase) and dismutase
(high oxy con on top of tube)

Question 8

facultative anaerobe

Answer 8

prefer oxygen
grow in the presensce or absence of oxygen
produce SOD and catalase
can carry out respiration and fermentation

Question 9

examples of obligate aerobes

Answer 9

1) micrococcus and corynebacterium (skin)
2) pseudomonas aeruginosa (burn infections)
3) bordetella pertussis (whooping cough)
4) mycobacterium tuberculosis (lung disease tuberculosis)

Question 10

examples of facultative anaerobes

Answer 10

1) escherichia coli, salmonella, shigella (LI)
2) staphylococcus (s.aureus)
3) saccharomyces (s. cereviceae) (bakers yeast/produces alcohol in the absense of oxygen)

Question 11

aerotolerant anaerobe

Answer 11

ignore oxygen
similar to anaerobes (do not require oxygen)
produce SOD and some catalase

Question 12

examples of aerotolerant anaerobes

Answer 12

1)lactobacillus (lactic acid rods in the vagia used to keep acidic environment
2)streptococcus (lactic acid cocci)
- streptococcus pyogenes- sore throat, tonsilitis, scarlet fever
streptococcus pneumoniae- bacterial pneummiae

Question 13

strict anaerobe

Answer 13

oxygen is toxic
do not produce either SOD or catalase
mostly carry out fermentation

Question 14

examples of strict anaerobes

Answer 14

1) clostridium tetani (reduces toxin related to tetanus)
2)clostridium botulinum (unsealed foods)
3)clostridium difficle
4) bacteriodes (normal itenstinal flora associated with appendicitus)

Question 15

microaerophile

Answer 15

requires less oxygen
growth occurs only where a low concentration of oxygen has diffused into a medium
produce SOD and catalase

Question 16

examples of microaerophiles

Answer 16

1) neisseria spp (pathogenic/nonpathogenic species
- neisseria gonorrheae (STD- gonorrhea)
-neisseria meningitidis (meningitis)

Question 17

physical requirements

Answer 17

-temperature
-pH
-osmotic pressure
-radiation, atmospheric pressure

Question 18

psychrophiles

Answer 18

love cold temperature
found in deep sea, polar regions
min-10 degrees
opt.15 degrees
max 20 degrees

Question 19

psychrotrophs

Answer 19

tolerate cold temp
cause spoilage of refigerated foods
min 0 degrees
opt 25 degrees
max 30 degrees

Question 20

mesophiles

Answer 20

require moderate temp
cause food spoilage and diseases
min 15 degrees
opt 20-40 degrees
max 45 degrees

Question 21

thermophiles

Answer 21

love high temp
not considered health problems
min 45 degrees
opt 55-70 degrees
max 80 degrees

Question 22

hyperthermophiles

Answer 22

love extreme high temp
grow near deep sea vents
min 65 degrees
opt 85-95 degrees
max 105 degrees

Question 23

what are the 3 types of organisms based on growth optimum pH?

Answer 23

acidophiles 0-5.5 pH (acidic)
neutrophiles 5.5-8 pH (neutral)
alkalophiles 8.5-11.5 pH (basic/alkaline)

Question 24

helicobacter pylori

Answer 24

lives in stomach under mucus layer and cuases stomach ulcers by weakening the mucus layer

Question 25

hypertonic solution

Answer 25

more salt in the solution then outside the cell. water flows from the cell so the cytoplasm will shrink (plasmolysis) high con outside cell low con inside cell

Question 26

hypotonic solution

Answer 26

more salt inside the cell then outside high con inside cell low con outside cell

Question 27

isotonic solution

Answer 27

organisms thrive because there is an equal amount of solute and water

Question 28

4 different microorganisms based on salt concentration

Answer 28

1) halophile- grow optimally at more then 0.2M - salt lovers 2) nonhalophiles- grow at less then 0.2M NaCl con 3) facultative halophiles- prefer non-salt envrionment but can grow in the presence of salt 4) extreme (obligate) halophiles- require more then 0.2M (30% salt)- organism that requires high salt con for growth

Question 29

bacterial growth requirements

Answer 29

chemical- carbon, oxygen, nitrogen, sulpher, etc physcial- temperature, pH, osmotic pressure

Question 30

culture medium

Answer 30

nutrients prepared for microbial growth

Question 31

sterile

Answer 31

no living microbes

Question 32

inoculum

Answer 32

microbes introduced into the medium

Question 33

culture

Answer 33

microbes growing in/on culture medium

Question 34

culture medium can be: (3)

Answer 34

1) liquid (broth) 2) semi-solid (deeps) 3) solid (plate)

Question 35

agar

Answer 35

complex polysacharide used as solidifying agent for culture media in petri plates, slants, and deeps generally not metabolized by microbes liquifies at 100 degrees solifies at 40 degrees

Question 36

complex/non-synthetic

Answer 36

same components not known or quantified (nutrient agar and broth)

Question 37

"enriched" functional type of media

Answer 37

nutrients that favor growth of select bacteria ex. blood agar, chocolate agar (grow organism)

Question 38

"differential" functional type of media

Answer 38

distinguises bateria growing on the same plate ex. blood agar (used to tell things apart- looking at what is now growing)

Question 39

"selective" functional type of media

Answer 39

encourages growth of some particular bacteria while suppressing growth of unwanted bacteria ex. MacConkey agar (introduces chemical that discourages one bacteria but encouraes another, one group growing and other not)

Question 40

BSL1

Answer 40

low individual and community risk microoganism that handle in a basic microbiology teaching lab ex. nonpathogenic E.coli, yeast

Question 41

BSL2

Answer 41

moderate individual risk, low community risk microorganisms that present a moderate risk for infection; operators should wear gloves, lab coats, etc

Question 42

BSL3

Answer 42

high individual risk, low community risk microorganisms are highly infectious airborne pathogens; the lab should be negatively pressuraized and equipped with air filters to prevent the release of pathogens ex- mycobacterium tuberculosis, bacillus anthracis, west nile virus, SARS corona virus, salmonella typhi

Question 43

BSL4

Answer 43

high individual risk, high community risk microorganisms are highly infectious airborne pathogen. No known cure. ex- ebola virus, lassa virus, small pox

Question 44

4 different ways bacteria can divide by

Answer 44

1) binary fission (one cell divides into 2 daughter cells 2) budding (one cell produces a small bud which pinches off to become its own cell) 3) condiospores (formation of spores, reproductive spores, one bacteria forms, spores can germinate to become independent cells) 4) fragmentation (organism breaks into pieces of an organism and starts a life as a new organism)

Question 45

lag phase

Answer 45

making new enzymes in response to new medium, intense activity preparing for population growth but no increase in population

Question 46

4 phases of growth

Answer 46

1) lag phase 2) log phase 3) stationary phase 4) death phase

Question 47

log phase

Answer 47

exponential growth most senstive to drugs and radiation during this period logarithmic gorwth due to reproduction by binary fission (bacteria) or mitosis (yeast)

Question 48

stationary phase

Answer 48

nutrients becoming limiting or waste products becoming toxic death rate= division rate period of equilibrium; microbial deaths balance production of new cells

Question 49

death phase

Answer 49

death exceeds division population is decreasing at a logarithmic rate