MCB 3023 Exam 3 Ques ons and answers | Updated
RATED A+ | 2026
Some anoxygenic photosynthe c bacteria are able to use _______ as an electron source.
nitrate
Fe3+
H2O
H2S
CO2
H2S
Which of these is true for a chemoorganoheterotroph?
Uses organic carbon as an electron source and a carbon source
Uses organic carbon as an electron source and inorganic carbon as a carbon source
Uses inorganic carbon as an energy source and a carbon source
Uses inorganic carbon as an energy source and organic carbon as a carbon source
Uses inorganic carbon as an electron source and organic carbon as a carbon source
Uses organic carbon as an electron source and a carbon source
Cyanobacteria carry out oxygenic photosynthesis producing oxygen as a byproduct from the
oxida on of water, which serves as the electron donor for the light-dependent reac ons. How
would cyanobacteria be classified?
photoorganoautotroph
photolithoheterotroph
photolithoautotroph
chemoorganoautotroph
chemoorganoheterotroph
photolithoautotroph
The most common lipids in the cell are synthesized from __________ and __________.
fa+y acids and sterol
fa+y acids and hopanoids
fa+y acids and glycerol
,glycerol and hopanoids
hopanoids and sterols
fa+y acids and glycerol
Oxida ve phosphoryla on requires ALL of the following for energy produc on EXCEPT:
pyruvate synthase
membrane-associated electron transport chain
a proton mo ve force
electrons from NADH
an ATP synthase
pyruvate synthase
Where is the reac on center of photosystems located?
Either in the cytoplasm or within a membrane
In the periplasmic space
In the cytoplasm
Within the cell wall
Within a biological membrane
Within a biological membrane
Which of these best describes assimilatory sulfate reduc on?
An energy yielding process
The reduc on of sulfate to elemental sulfur
The reduc on of sulfate for incorpora on into cellular material
The reduc on of sulfate to sulfide for excre on by the cell
A type of anaerobic respira on
The reduc on of sulfate for incorpora on into cellular material
What is the term for the primary pathway for fa+y acid oxida on?
β-oxida on pathway
Parnas pathway
Pentose phosphate pathway
Calvin cycle
reduc ve TCA pathway
, β-oxida on pathway
Microorganisms that rely solely on fermenta on reac ons for energy produc on make ATP
primarily by this method.
photo-oxida on of NADH
electron transport phosphoryla on
membrane bound ATPase
substrate-level phosphoryla on
oxida ve phosphoryla on
substrate-level phosphoryla on
How do enzymes increase the rate of a biochemical reac on?
By lowering the ac va on energy
By lowering the ΔG0'
By increasing the ac va on energy
By increasing the standard free energy
By lowering the reduc on poten al
By lowering the ac va on energy
Which organisms contain bacteriochlorophyll?
cyanobacteria and plants
cyanobacteria and purple non-sulfur bacteria
cyanobacteria, purple sulfur bacteria, and green sulfur bacteria
purple sulfur, purple non-sulfur, and green sulfur bacteria
cyanobacteria and green sulfur bacteria
purple sulfur, purple non-sulfur, and green sulfur bacteria
When oxygen gas reacts with hydrogen gas water is produced as the product in this oxida on-
reduc on reac on. Hydrogen donates electrons to elemental oxygen in the reac on. Which
statement below is true about this reac on?
The electron donor in this reac on is reduced
Oxygen is being reduced in the reac on
Oxygen is oxidized to water
Hydrogen is being reduced in the reac on
The electron acceptor in this reac on is oxidized
RATED A+ | 2026
Some anoxygenic photosynthe c bacteria are able to use _______ as an electron source.
nitrate
Fe3+
H2O
H2S
CO2
H2S
Which of these is true for a chemoorganoheterotroph?
Uses organic carbon as an electron source and a carbon source
Uses organic carbon as an electron source and inorganic carbon as a carbon source
Uses inorganic carbon as an energy source and a carbon source
Uses inorganic carbon as an energy source and organic carbon as a carbon source
Uses inorganic carbon as an electron source and organic carbon as a carbon source
Uses organic carbon as an electron source and a carbon source
Cyanobacteria carry out oxygenic photosynthesis producing oxygen as a byproduct from the
oxida on of water, which serves as the electron donor for the light-dependent reac ons. How
would cyanobacteria be classified?
photoorganoautotroph
photolithoheterotroph
photolithoautotroph
chemoorganoautotroph
chemoorganoheterotroph
photolithoautotroph
The most common lipids in the cell are synthesized from __________ and __________.
fa+y acids and sterol
fa+y acids and hopanoids
fa+y acids and glycerol
,glycerol and hopanoids
hopanoids and sterols
fa+y acids and glycerol
Oxida ve phosphoryla on requires ALL of the following for energy produc on EXCEPT:
pyruvate synthase
membrane-associated electron transport chain
a proton mo ve force
electrons from NADH
an ATP synthase
pyruvate synthase
Where is the reac on center of photosystems located?
Either in the cytoplasm or within a membrane
In the periplasmic space
In the cytoplasm
Within the cell wall
Within a biological membrane
Within a biological membrane
Which of these best describes assimilatory sulfate reduc on?
An energy yielding process
The reduc on of sulfate to elemental sulfur
The reduc on of sulfate for incorpora on into cellular material
The reduc on of sulfate to sulfide for excre on by the cell
A type of anaerobic respira on
The reduc on of sulfate for incorpora on into cellular material
What is the term for the primary pathway for fa+y acid oxida on?
β-oxida on pathway
Parnas pathway
Pentose phosphate pathway
Calvin cycle
reduc ve TCA pathway
, β-oxida on pathway
Microorganisms that rely solely on fermenta on reac ons for energy produc on make ATP
primarily by this method.
photo-oxida on of NADH
electron transport phosphoryla on
membrane bound ATPase
substrate-level phosphoryla on
oxida ve phosphoryla on
substrate-level phosphoryla on
How do enzymes increase the rate of a biochemical reac on?
By lowering the ac va on energy
By lowering the ΔG0'
By increasing the ac va on energy
By increasing the standard free energy
By lowering the reduc on poten al
By lowering the ac va on energy
Which organisms contain bacteriochlorophyll?
cyanobacteria and plants
cyanobacteria and purple non-sulfur bacteria
cyanobacteria, purple sulfur bacteria, and green sulfur bacteria
purple sulfur, purple non-sulfur, and green sulfur bacteria
cyanobacteria and green sulfur bacteria
purple sulfur, purple non-sulfur, and green sulfur bacteria
When oxygen gas reacts with hydrogen gas water is produced as the product in this oxida on-
reduc on reac on. Hydrogen donates electrons to elemental oxygen in the reac on. Which
statement below is true about this reac on?
The electron donor in this reac on is reduced
Oxygen is being reduced in the reac on
Oxygen is oxidized to water
Hydrogen is being reduced in the reac on
The electron acceptor in this reac on is oxidized
