BIOL 2051 Lab Final Questions and All
Actual Answers 2025-2026 Updated.
What is the reagent that serves as the substrate in the catalase test? - Answer hydrogen
peroxide
what type of metabolism is associated with catalase production? - Answer aerobic
respiration
for what product is one testing when using the catalase test? - Answer cytochrome c oxidase
would you expect aerobes to produce catalase? - Answer No, catalase enzymes are made by
organisms that produce energy using aerobic respiration
describe the appearance of a positive and negative catalase test? - Answer -Positive: within
seconds the microorganism will turn blue/purple where the oxidase reagent was added
-Negative: little or no color change
What does a positive or negative catalase test indicate about the metabolism of the cells
tested? - Answer -a positive test indicates the cells undergo aerobic respiration
-a negative test indicates the cells are facultative anaerobes
If the catalase test is positive, what two possible genera could the microorganism belong? -
Answer -Bacillus or Escherichia
What is the equation catalyzes by the enzyme catalase? - Answer 2 H2O2 -> 2 H2O + O2
Would you expect your cells to produce catalase? - Answer yes, because they undergo
aerobic respiration
what is the function of cytochrome oxidase? - Answer cytochrome donates a proton to
oxygen in the electron transport chain reducing oxygen
Why are strict aerobes oxidase positive? - Answer
the oxidase test is used to differentiate among which groups of bacteria? - Answer genera
, What is the function of the oxidase reagent in this procedure? - Answer artificial substrate to
be oxidized by cytochrome c oxidase
what type of metabolism was chlamydomonas using in the light? were both WT and mutant
capable of this type of metabolism? - Answer -oxygenic photosynthesis
-yes
what type of metabolism was chlamydomonas using in the dark? were both WT and mutant
capable of this type of metabolism? - Answer -aerobic respiration using acetate as an
electron source
-no, only WT
the dk mutant lacks a functional cytochrome oxidase. Explain how this prevents the mutant
from growing in the dark, but does not prevent the mutant from growing in the light. - Answer
it requires an electron source in the dark
In anaerobic respiration, what is used as the external electron acceptor?
Why is it termed anaerobic? - Answer -S04-, CO3-, NO3-
-occurs in the absence of free oxygen
How does denitrification differ from nitrogen fixation? - Answer -denitrification reduces
nitrate to dinitrogen gas and may result in the depletion of nitrogen from the soil.
-Nitrogen fixation maintains the balance of nitrogen in the ecosystem.
What do these results indicate about the organism's ability to reduce nitrate?
-there was no gas in the Durham assembly.
-Addition of alpha naphthylamine acetate and sulfanilic acid caused the broth to turn red. -
Answer -can reduce to NO2-
What do these results indicate about the organism's ability to reduce nitrate?
-Gas was present in the Durham assembly - Answer -can reduce to N2
What do these results indicate about the organism's ability to reduce nitrate?
-no gas was present in the Durham assembly
-the alpha naphthylamine acetate and sulfanilic acid were added and no color change occurred
-zinc was added and the solution turned red - Answer -NO3- was not reduced
Actual Answers 2025-2026 Updated.
What is the reagent that serves as the substrate in the catalase test? - Answer hydrogen
peroxide
what type of metabolism is associated with catalase production? - Answer aerobic
respiration
for what product is one testing when using the catalase test? - Answer cytochrome c oxidase
would you expect aerobes to produce catalase? - Answer No, catalase enzymes are made by
organisms that produce energy using aerobic respiration
describe the appearance of a positive and negative catalase test? - Answer -Positive: within
seconds the microorganism will turn blue/purple where the oxidase reagent was added
-Negative: little or no color change
What does a positive or negative catalase test indicate about the metabolism of the cells
tested? - Answer -a positive test indicates the cells undergo aerobic respiration
-a negative test indicates the cells are facultative anaerobes
If the catalase test is positive, what two possible genera could the microorganism belong? -
Answer -Bacillus or Escherichia
What is the equation catalyzes by the enzyme catalase? - Answer 2 H2O2 -> 2 H2O + O2
Would you expect your cells to produce catalase? - Answer yes, because they undergo
aerobic respiration
what is the function of cytochrome oxidase? - Answer cytochrome donates a proton to
oxygen in the electron transport chain reducing oxygen
Why are strict aerobes oxidase positive? - Answer
the oxidase test is used to differentiate among which groups of bacteria? - Answer genera
, What is the function of the oxidase reagent in this procedure? - Answer artificial substrate to
be oxidized by cytochrome c oxidase
what type of metabolism was chlamydomonas using in the light? were both WT and mutant
capable of this type of metabolism? - Answer -oxygenic photosynthesis
-yes
what type of metabolism was chlamydomonas using in the dark? were both WT and mutant
capable of this type of metabolism? - Answer -aerobic respiration using acetate as an
electron source
-no, only WT
the dk mutant lacks a functional cytochrome oxidase. Explain how this prevents the mutant
from growing in the dark, but does not prevent the mutant from growing in the light. - Answer
it requires an electron source in the dark
In anaerobic respiration, what is used as the external electron acceptor?
Why is it termed anaerobic? - Answer -S04-, CO3-, NO3-
-occurs in the absence of free oxygen
How does denitrification differ from nitrogen fixation? - Answer -denitrification reduces
nitrate to dinitrogen gas and may result in the depletion of nitrogen from the soil.
-Nitrogen fixation maintains the balance of nitrogen in the ecosystem.
What do these results indicate about the organism's ability to reduce nitrate?
-there was no gas in the Durham assembly.
-Addition of alpha naphthylamine acetate and sulfanilic acid caused the broth to turn red. -
Answer -can reduce to NO2-
What do these results indicate about the organism's ability to reduce nitrate?
-Gas was present in the Durham assembly - Answer -can reduce to N2
What do these results indicate about the organism's ability to reduce nitrate?
-no gas was present in the Durham assembly
-the alpha naphthylamine acetate and sulfanilic acid were added and no color change occurred
-zinc was added and the solution turned red - Answer -NO3- was not reduced
