BACTERIA NUTRITION AND GROWTH

Question 1

physical requirement for growth ?

Answer 1

temperature, pH, oxygen, osmotic pressure

Question 2

chemical requirement for growth ?

Answer 2

carbon, nitrogen sulfur, oxygen, trace elements

Question 3

explain temperature effects ?

Answer 3

minimum - lowest temp where microbes will grow
optimum- growth rate is fastest
maximum- highest temp where microbes will grow

Question 4

explain pH and microbial growth ?

Answer 4

the internal pH of cell must close to neutral
acidophile (1-4) - grow best in low pH (H pylori)
alkalophile (8.5-11) - grow best in high pH (vibrio)
neutrophile - most pathogenic bacteria

Question 5

differentiate thrive and tolerate osmotic effect

Answer 5

thrive : solute osmophile, salt halophile, pressure barophile
tolerate : solute osmotolerant, salt halotolerant, pressure barotolerant

Question 6

how moisture affect growth

Answer 6

depends, some need humid/ some dry

Question 7

how oxygen affect growth

Answer 7

utilization of o2 produce toxic produce and it has SUPEROXIDE DISMUTASE and CATALASE to convert back to harmless substance

Question 8

o2 > h2o2 + o2 is by

Answer 8

SOD

Question 9

h2o2 > h20 + o2

Answer 9

catalase

Question 10

aerobes types

Answer 10

obligate -wajib o2
facultative - w/wout survive (+SOD, +catalase)
microaerophiles - kena reduce o2 level (SOD, +-catalase)

Question 11

anaerobe types

Answer 11

obligate -killed if has o2 (-SOD, -catalase)

aerotolerant -tolerate o2 tapi better wout (+SOD, -catalase)

Question 12

what is used to remove oxygen in anaerobes?

Answer 12

thioglycollate

Question 13

what is culture media?

Answer 13

nutrient material preapared for microbial growth in lab

its sterile, hv appropriate nutrients&temp , incubated

Question 14

defined medium is

Answer 14

precise amt of highly purified chemicals

Question 15

complex medium is

Answer 15

highly nutritious substances

Question 16

types of media

Answer 16

physical , chemical, functional

Question 17

explain liquid media

Answer 17

water based solutions, not solidify, measure turbidity growth of microbes, ex : nutrient broth, methylene blue milk

Question 18

what is semi solid media ?

Answer 18

clot like at room temp, determine motility of bacteria, used o localized reaction a specific site, ex: sulfide indole motility

Question 19

what is solid media example?

Answer 19

gelatin agar, cooked meat media, potato slices

Question 20

state 2 types of chemical composition of culture media

Answer 20

synthetic media - hv exact formula

complex, non synthetic -contain not chemically definable

Question 21

what is selective media ?

Answer 21

inhibit growth of one microbe and encourage other specific one
ex: manittol salt agar

Question 22

what is differential media ?

Answer 22

media that show visible changes in colony size, colour or formation of gas bubbles and precipitates
ex: blood agar macconkey)

Question 23

what is enrichment agar ?

Answer 23

used to encourage growth of particular organism in mixed culture ex: choc agar, slenite F broth

Question 24

pure culture is

Answer 24

culture that contains only a single species or strain of organism

Question 25

what is streak plate used for ?

Answer 25

isolate the pure culture

Question 26

what is colony ?

Answer 26

population of cells arising from single cell or spore from group of attached cells

Question 27

how cell divison and growth works ?

Answer 27

thru binary fission where it hv septum that separate 2 daughter cell , budding (unequal cell divison from parent cell)

Question 28

explain phase of growth

Answer 28

lag phase : cells recover from a period of no cell growth and making macromolecules in preparation for growth
log phase : culures grow maximally
stationary phase : nutrients depleted, waste accumulates
death phase > growth phase