MMBIO 221 TEST QUESTIONS AND ANSWERS A+
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Fermenting bacteria grow fairly slowly and produce lots of fermentation products.
What is the best reason for why they grow slowly?
They only produce 2 ATPs from glycolysis during fermentation.
Which of the following best describes the role of the citric acid cycle (TCA or
Kreb's cycle)?
To sequentially break carbon-carbon bonds and make NADH or FADH2.
In aerobic cellular respiration, which generates more ATP, substrate-level
phosphorylation or oxidative phosphorylation?
Oxidative phosphorylation
Lactic acid and ethanol are the only substances produced by fermenting
microorganisms.
False
The enzyme that phosphorylates ADP using a chemiosmotic proton motive force
is
ATP synthase
How many ATPs (net) are made in glycolysis?
2
The physical barrier that permits a proton motive force to be made, and which
allows chemiosmotic ATP synthesis to occur, is the
Plasma Membrane
What role does O2 play in aerobic respiration?
It is an electron acceptor
Fermenting bacteria grow fairly slowly and produce lots of fermentation products.
What is the best reason for why they grow slowly?
They only produce 2 ATPs from glycolysis during fermentation.
The reaction below shows the conversion of phosphoenolpyruvate to pyruvate
and the simultaneous phosphorylation of ADP to make ATP. Of the following
terms, which best describes the type of reaction where phosphoenolpyruvate is
converted to pyruvate?
Substrate level phosphorylation
Leuconostoc mesenteroides is lactic acid bacterium used in the production of
sauerkraut. Its only fermentation product is lactic acid. How might this bacterium
be characterized?
It is a homolactate fermenter.
During oxidative phosphorylation, electrons are moved through the electron
transport chain to a terminal electron acceptor. What other critically important
process occurs as electrons are moved through the electron transport chain?
Protons are moved through the membrane to create a proton motive force.
What substance is regenerated in fermentation reactions?
NAD+
, Fermentation is a wasteful process because the cell secretes carbon-carbon
bonds and also wastes
electrons temporarily stored in NADH
Cellular respiration makes ATP and serves what other function in the cell?
It makes biosynthetic precursor molecules
Leuconostoc mesenteroides is lactic acid bacterium used in the production of
sauerkraut. Its only fermentation product is lactic acid. How might this bacterium
be characterized?
It is a homolactate fermenter.
In glycolysis, fructose-6-phosphate is phosphorylated by phosphofructokinase to
make fructose-1,6-bisphosphate. What is the consequence of adding a second
electronegative functional group to fructose-6-phosphate in this reaction?
The bond between the third and fourth carbon atoms in fructose-1,6-bisphosphate is
weakened.
In the tricarboxylic acid (TCA) cycle, carbon atoms (as CO2) are sequentially
broken off of molecules such as isocitrate. The electrons are passed to NAD+
making NADH. This electron transport molecule then transfers its electrons to the
electron transport chain and a proton motive force (PMF) is established. The PMF
is then used to generate ATP using ATP synthase. Of the following terms, which
best describes the type of reaction where ATP is generated?
Oxidative phosphorylation
In aerobic cellular respiration, which generates more ATP, substrate-level
phosphorylation or oxidative phosphorylation?
Oxidative phosphorylation
The reaction shown below is an enzymatically catalyzed redox reaction that
occurs in fermentation. In this reaction, an enzyme performs an oxidation
reaction with a concomitant reduction reaction. Which of the substrates and
products produced by the reaction is being reduced (that is, accepting
electrons)?
pyruvate
The reaction below shows the conversion of phosphoenolpyruvate (PEP) to
pyruvate and the simultaneous phosphorylation of ADP to make ATP. Of the
following terms, which best describes the type of reaction when ADP is
phosphorylated?
Endergonic reaction
Molecules, such as glucose, function as fuels in catabolic reactions. At a
fundamental level, what role does a fuel have in catabolism?
It is an electron donor
An exergonic reaction is one that
the reactants have more energy than the products
Enzymes make reactions go ______________ by ______________ the activation
energy of the reaction.
Faster; Lowering
In enzymatic reactions, enzymes react with substrates to produce an enzyme-
substrate complex and then the reaction proceeds and products are formed. This
is represented in the figure below.
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Fermenting bacteria grow fairly slowly and produce lots of fermentation products.
What is the best reason for why they grow slowly?
They only produce 2 ATPs from glycolysis during fermentation.
Which of the following best describes the role of the citric acid cycle (TCA or
Kreb's cycle)?
To sequentially break carbon-carbon bonds and make NADH or FADH2.
In aerobic cellular respiration, which generates more ATP, substrate-level
phosphorylation or oxidative phosphorylation?
Oxidative phosphorylation
Lactic acid and ethanol are the only substances produced by fermenting
microorganisms.
False
The enzyme that phosphorylates ADP using a chemiosmotic proton motive force
is
ATP synthase
How many ATPs (net) are made in glycolysis?
2
The physical barrier that permits a proton motive force to be made, and which
allows chemiosmotic ATP synthesis to occur, is the
Plasma Membrane
What role does O2 play in aerobic respiration?
It is an electron acceptor
Fermenting bacteria grow fairly slowly and produce lots of fermentation products.
What is the best reason for why they grow slowly?
They only produce 2 ATPs from glycolysis during fermentation.
The reaction below shows the conversion of phosphoenolpyruvate to pyruvate
and the simultaneous phosphorylation of ADP to make ATP. Of the following
terms, which best describes the type of reaction where phosphoenolpyruvate is
converted to pyruvate?
Substrate level phosphorylation
Leuconostoc mesenteroides is lactic acid bacterium used in the production of
sauerkraut. Its only fermentation product is lactic acid. How might this bacterium
be characterized?
It is a homolactate fermenter.
During oxidative phosphorylation, electrons are moved through the electron
transport chain to a terminal electron acceptor. What other critically important
process occurs as electrons are moved through the electron transport chain?
Protons are moved through the membrane to create a proton motive force.
What substance is regenerated in fermentation reactions?
NAD+
, Fermentation is a wasteful process because the cell secretes carbon-carbon
bonds and also wastes
electrons temporarily stored in NADH
Cellular respiration makes ATP and serves what other function in the cell?
It makes biosynthetic precursor molecules
Leuconostoc mesenteroides is lactic acid bacterium used in the production of
sauerkraut. Its only fermentation product is lactic acid. How might this bacterium
be characterized?
It is a homolactate fermenter.
In glycolysis, fructose-6-phosphate is phosphorylated by phosphofructokinase to
make fructose-1,6-bisphosphate. What is the consequence of adding a second
electronegative functional group to fructose-6-phosphate in this reaction?
The bond between the third and fourth carbon atoms in fructose-1,6-bisphosphate is
weakened.
In the tricarboxylic acid (TCA) cycle, carbon atoms (as CO2) are sequentially
broken off of molecules such as isocitrate. The electrons are passed to NAD+
making NADH. This electron transport molecule then transfers its electrons to the
electron transport chain and a proton motive force (PMF) is established. The PMF
is then used to generate ATP using ATP synthase. Of the following terms, which
best describes the type of reaction where ATP is generated?
Oxidative phosphorylation
In aerobic cellular respiration, which generates more ATP, substrate-level
phosphorylation or oxidative phosphorylation?
Oxidative phosphorylation
The reaction shown below is an enzymatically catalyzed redox reaction that
occurs in fermentation. In this reaction, an enzyme performs an oxidation
reaction with a concomitant reduction reaction. Which of the substrates and
products produced by the reaction is being reduced (that is, accepting
electrons)?
pyruvate
The reaction below shows the conversion of phosphoenolpyruvate (PEP) to
pyruvate and the simultaneous phosphorylation of ADP to make ATP. Of the
following terms, which best describes the type of reaction when ADP is
phosphorylated?
Endergonic reaction
Molecules, such as glucose, function as fuels in catabolic reactions. At a
fundamental level, what role does a fuel have in catabolism?
It is an electron donor
An exergonic reaction is one that
the reactants have more energy than the products
Enzymes make reactions go ______________ by ______________ the activation
energy of the reaction.
Faster; Lowering
In enzymatic reactions, enzymes react with substrates to produce an enzyme-
substrate complex and then the reaction proceeds and products are formed. This
is represented in the figure below.
