quiz 2

Question 1

what mechanism do bacteria use to grow?

Answer 1

binary fission, Division of one cell to two daughter cells

Question 2

what is generation time?

Answer 2

time required for one cell to form two or time required for a population to double in number, influenced by environment.

Question 3

What is batch culture?

Answer 3

Organisms incubated in a flask or a tube with sterile media.

Question 4

What is the Lag phase in broth culture?

Answer 4

Phase where cell numbers remain unchanged but cells have high metabolic activity, high levels of protein synthesis and cell composition. Acclimatization

Question 5

What is the Log phase in broth culture?

Answer 5

population grows at maximum rate possible, exponential cell # increase

Question 6

What is the stationery phase in broth culture?

Answer 6

individual cells grow very slowly, total cell number remains constant

Question 7

What is the death phase in broth culture?

Answer 7

culture dies, cells die

Question 8

Describe asymmetric division in sporulation.

Answer 8

Cell asymmetrically divides into large mother cell and smaller foreshore. Forespore is engulfed by mother cell, becoming the endospore.

Question 9

What is the moth-endospore complex called in sporulation?

Answer 9

Mother-endospore complex is called the sporangium

Question 10

What cell types often have sporulation?

Answer 10

Bacillus and clostridium

Question 11

What are the morphologies for bacillus and clostridium?

Answer 11

gram positive, rod shaped, motile and long chain

Question 12

What are key traits of bacillus?

Answer 12

obligate aerobe via respiration or facultative anaerobe via respiration or fermentation, catalase positive

Question 13

What are key traits of clostridium?

Answer 13

obligate anaerobe that ferments, catalase negative, aeroduric

Question 14

What does it mean for a bacteria to be an aeroduric anaerobe?

Answer 14

oxygen resistant even though requires anoxic conditions, can survived in prolonged oxygen but won’t reproduce

Question 15

What is catalase? What is the catalase test?

Answer 15

catalase works with enzyme to protect cells against toxic species.
converts hydrogen peroxide to H2O and molecular O2. Found in aerobes and facultative anaerobes, catalase only expressed with oxygen exposure.

Question 16

What are Pseudomonads?

Answer 16

rod shaped, gram negative proteobacteria, obligate respires that use oxygen as term e- acceptor. Have a positive oxidase test.
Can be pathogenic

Question 17

Why is pseduomonads unusual?

Answer 17

Commonly used as bioremediation bc they rapidly metabolize and oxidize unusual compounds.

Question 18

What is the oxidase test?

Answer 18

identifies cytochrome C. oxidase which the terminal oxidase in electron transport chain
-catalyzes the transfer of electrons from electron carrier to oxygen
-bacteria is oxidase negative when it does not use etc

Question 19

micrococcus morphology

Answer 19

gram positive, diploid or tetras cocci, obligate aerobe
will have pink rim around purple body, catalase positive

Question 20

staphylococcus morphology

Answer 20

gram positive, random and irregular cocci, facultative aerobe and acidic on glycerol

Question 21

What is the terminology for negative, positive and positive w/gas test.

Answer 21

Negative if culture is yellow:NC
positive if pink color change: A
positive if pink with bubbles(fermentation): AG

Question 22

describe the acetoin test

Answer 22

acetoin is metabolic intermediate when cells use the butanediol fermentation pathway to ferment glucose. in presence of potassium hydroxide, acetoin is converted to diacetyl, with the addition of creatine, the mixture turns dark red. Peptone broth is the source of creatine

Question 23

What reaction is taking place in the nitrate reduction test

Answer 23

denitrification: Nitrate->nitrite-> N2 and ammonia, absence of nitrite is either bc we don’t have a nitrate reducer or that we have a nitrite reducer, so we made N2 and NH3

Question 24

How do we determine the results of a nitrate reduction test?

Answer 24

If color after adding A+B->(+) results nitrate was converted to nitrite
if color after zinc added->negative result, organism did not convert nitrate
if no color change after zinc->(+) result, organism reduced nitrate to ammonia and N2

Question 25

What is propionic bacteria?

Answer 25

produce propionic acid-> obligate anaerobe that grows via fermentation. Utilizes lactic acid as substrate

Question 26

what is the morphology of propionic bacteria?

Answer 26

aeroduric, gram positive, nonmotile, diphtheroids

Question 27

What is an an oxygenic phototroph?

Answer 27

Do not produce O2 because have no PS2 so cannot use H2O as electron donor

Question 28

Green and Purple sulfur bacteria

Answer 28

obligate aerobes that require high H2S as a electron donor

Question 29

Green gliding and purple nonsulfur

Answer 29

grow in presence of oxygen inhibited by high levels of sulfide, use H2 as electron donors

Question 30

purple non sulfur morphology

Answer 30

gram negative, motile, various shapes.
Capable of photohetotrophic growth via respiration when aerobic