AP Biology Unit 3 Cellular Energetics
Exam Practice Test Questions And
Answers
A researcher designs an experiment to investigate the effect of environmental
temperature on the function of an enzyme. For each trial included in the experiment, the
researcher will add the enzyme and its substrate to an aqueous buffer solution and then
measure the amount of product formed over 20 minutes.
Which of the following must remain the same for all trials of this experiment? -
ANSWER The initial concentration of the substrate
Which of the following questions will best direct an investigation of the mechanism of
ATP synthase? - ANSWER Is the phosphorylation of ADP by ATP synthase dependent
on the formation of a proton gradient?
To test the hypothesis that a particular plant synthesizes storage lipids by using
glyceraldehyde 3-phosphate (G3P) from photosynthesis, a researcher plans to use
radiolabeled precursors to track the molecules through the biosynthetic pathway. Which
of the following radiolabeled precursors is most appropriate for the researcher to use? -
ANSWER 14C-labeled CO2, because atmospheric carbon is fixed to carbohydrates by
photosynthesis
A researcher proposes a model of an enzyme-catalyzed reaction in which a reactant is
converted to a product. The model is based on the idea that the reactant passes
through a transition state within the enzyme-substrate complex before the reactant is
converted to the product.
Which of the following statements best helps explain how the enzyme speeds up the
reaction? - ANSWER The enzyme's active site binds to and stabilizes the transition
state, which decreases the activation energy of the reaction.
The enzyme hexokinase catalyzes the conversion of glucose to glucose-6-phosphate,
which is an important step in glycolysis. The reaction involves the transfer of a
phosphate group from ATP to glucose.
, Either a glucose molecule or a water molecule can fit in the active site of hexokinase.
The presence of a water molecule in hexokinase's active site would result in the
hydrolysis of ATP to ADP instead of the conversion of glucose to glucose-6-phosphate.
According to the data, the crickets at 25oC have greater oxygen consumption per gram
of tissue than do the crickets at 10oC. This trend in oxygen consumption is the opposite
of that in the mice. The difference in trends in oxygen consumption among crickets and
mice is due to their - ANSWER mode of internal temperature regulation
The figures can best assist in ANSWERing which of the following questions? -
ANSWER Do electron transport chains create a gradient so that ATP synthase can
generate ATP molecules?
In an experiment, a scientist isolates mitochondria from living cells and suspends them
in two different buffered solutions. One solution is maintained at pH 4, while the other
solution is maintained at pH 9. The scientist finds that mitochondria in the solution at pH
4 continue to produce ATP but those in the pH 9 solution do not.
The results of the experiment can be used as evidence in support of which of the
following scientific claims about mitochondrial activity? - ANSWER ATP production in
mitochondria requires a hydrogen ion gradient that favors movement of protons into the
mitochondrial matrix.
Cyanobacteria contain a variety of pigment molecules, as shown in Table 1. As a result,
the color of cyanobacteria cultures can vary significantly based on the relative amount
of each pigment produced.
A researcher placed a culture of cyanobacteria under green lights. Within a few weeks,
the appearance of the cyanobacteria changed from green to red. The researcher
claimed the color change in the culture was the result of an adaptation allowing greater
photosynthesis.
Which of the following provides the best reasoning to justify the researcher's claim? -
ANSWER In green light, more phycoerythrin molecules are produced, allowing more
green light to be absorbed, thus increasing photosynthesis.
If an individual with diabetes consumes food that is high in simple carbohydrates, blood-
sugar levels can rise above normal levels. Which of the following questions would
provide the best direction for a researcher who wanted to study the impact of
abnormally high blood-sugar levels on cellular homeostasis in diabetics? - ANSWER
Does water move from cells into blood vessels more rapidly in diabetics than in
Exam Practice Test Questions And
Answers
A researcher designs an experiment to investigate the effect of environmental
temperature on the function of an enzyme. For each trial included in the experiment, the
researcher will add the enzyme and its substrate to an aqueous buffer solution and then
measure the amount of product formed over 20 minutes.
Which of the following must remain the same for all trials of this experiment? -
ANSWER The initial concentration of the substrate
Which of the following questions will best direct an investigation of the mechanism of
ATP synthase? - ANSWER Is the phosphorylation of ADP by ATP synthase dependent
on the formation of a proton gradient?
To test the hypothesis that a particular plant synthesizes storage lipids by using
glyceraldehyde 3-phosphate (G3P) from photosynthesis, a researcher plans to use
radiolabeled precursors to track the molecules through the biosynthetic pathway. Which
of the following radiolabeled precursors is most appropriate for the researcher to use? -
ANSWER 14C-labeled CO2, because atmospheric carbon is fixed to carbohydrates by
photosynthesis
A researcher proposes a model of an enzyme-catalyzed reaction in which a reactant is
converted to a product. The model is based on the idea that the reactant passes
through a transition state within the enzyme-substrate complex before the reactant is
converted to the product.
Which of the following statements best helps explain how the enzyme speeds up the
reaction? - ANSWER The enzyme's active site binds to and stabilizes the transition
state, which decreases the activation energy of the reaction.
The enzyme hexokinase catalyzes the conversion of glucose to glucose-6-phosphate,
which is an important step in glycolysis. The reaction involves the transfer of a
phosphate group from ATP to glucose.
, Either a glucose molecule or a water molecule can fit in the active site of hexokinase.
The presence of a water molecule in hexokinase's active site would result in the
hydrolysis of ATP to ADP instead of the conversion of glucose to glucose-6-phosphate.
According to the data, the crickets at 25oC have greater oxygen consumption per gram
of tissue than do the crickets at 10oC. This trend in oxygen consumption is the opposite
of that in the mice. The difference in trends in oxygen consumption among crickets and
mice is due to their - ANSWER mode of internal temperature regulation
The figures can best assist in ANSWERing which of the following questions? -
ANSWER Do electron transport chains create a gradient so that ATP synthase can
generate ATP molecules?
In an experiment, a scientist isolates mitochondria from living cells and suspends them
in two different buffered solutions. One solution is maintained at pH 4, while the other
solution is maintained at pH 9. The scientist finds that mitochondria in the solution at pH
4 continue to produce ATP but those in the pH 9 solution do not.
The results of the experiment can be used as evidence in support of which of the
following scientific claims about mitochondrial activity? - ANSWER ATP production in
mitochondria requires a hydrogen ion gradient that favors movement of protons into the
mitochondrial matrix.
Cyanobacteria contain a variety of pigment molecules, as shown in Table 1. As a result,
the color of cyanobacteria cultures can vary significantly based on the relative amount
of each pigment produced.
A researcher placed a culture of cyanobacteria under green lights. Within a few weeks,
the appearance of the cyanobacteria changed from green to red. The researcher
claimed the color change in the culture was the result of an adaptation allowing greater
photosynthesis.
Which of the following provides the best reasoning to justify the researcher's claim? -
ANSWER In green light, more phycoerythrin molecules are produced, allowing more
green light to be absorbed, thus increasing photosynthesis.
If an individual with diabetes consumes food that is high in simple carbohydrates, blood-
sugar levels can rise above normal levels. Which of the following questions would
provide the best direction for a researcher who wanted to study the impact of
abnormally high blood-sugar levels on cellular homeostasis in diabetics? - ANSWER
Does water move from cells into blood vessels more rapidly in diabetics than in
