AP Biology MCQ Practice Exam #1
Questions and Answers
Humans produce sweat as a cooling mechanism to maintain a stable internal
temperature. Which of the following best expalins how the properties of water
contribute to this physiological process?
✓ ~~~The high heat of vaporization of water allows the body to remove excess heat through
a phase change of water from liquid to gas.
A student placed a semipermeable membrane inside a U-shaped channel with two
chambers. Membrane permits the movement of water but not salt. The student
wants to vary the rate of osmosis that occurs across the membrane. Which
experimental design will result in the fastest net rate of water movement into
chamber A?
✓ ~~~Placing salt in chamber A and distilled water in chamber B.
What best describes the role of water in photosynthesis?
✓ ~~~Water molecules donate electrons to the electron transport chain.
What evolutionary advantage does compartmentalization of core metabolic
processes offer eukaryotes?
✓ ~~~Evolution of a nucleus in eukaryotes separates the processes of transcription and
translation and they can be regulated separately.
Pyruvate dehydrogenase is an enzyme that converts pyruvate to acetyl-CoA. Acetyl-
CoA is further metabolized in the Krebs cycle. A researcher measured the
, accumulation of acetyl-CoA in a reaction containing pyruvate and pyruvate
dehydrogenase under several different conditions
5. Which of the following best describes the cellular location where pyruvate
dehydrogenase is most likely active?
6. The maximum production rate of acetyl-CoA under condition 1 is closer to which
of the following?
7. Which of the following observations provides the best evidence that acetyl-CoA
negatively regulates pyruvate dehydrogenase activity?
8. Which of the following best explains the buildup of lactic acid in individuals with
the mutation?
✓ ~~~5. The mitochondrial matrix
6. 1 micromole/sec
7. The rate of pyruvate dehydrogenase-catalyzed reaction is slower in the presence
of a higher concentration of acetyl-CoA
8. Cells undergo fermentation because pyruvate cannot be metabolized to proceed
into the Krebs cycle
Which of the following best explains how water is able to move upward from the
roots of a plant, through its xylem in the stem, and out to the leaves?
✓ ~~~Water and the xylem are both polar. Water molecules have the ability to form
hydrogen bonds with each other and with the walls of the xylem.
Questions and Answers
Humans produce sweat as a cooling mechanism to maintain a stable internal
temperature. Which of the following best expalins how the properties of water
contribute to this physiological process?
✓ ~~~The high heat of vaporization of water allows the body to remove excess heat through
a phase change of water from liquid to gas.
A student placed a semipermeable membrane inside a U-shaped channel with two
chambers. Membrane permits the movement of water but not salt. The student
wants to vary the rate of osmosis that occurs across the membrane. Which
experimental design will result in the fastest net rate of water movement into
chamber A?
✓ ~~~Placing salt in chamber A and distilled water in chamber B.
What best describes the role of water in photosynthesis?
✓ ~~~Water molecules donate electrons to the electron transport chain.
What evolutionary advantage does compartmentalization of core metabolic
processes offer eukaryotes?
✓ ~~~Evolution of a nucleus in eukaryotes separates the processes of transcription and
translation and they can be regulated separately.
Pyruvate dehydrogenase is an enzyme that converts pyruvate to acetyl-CoA. Acetyl-
CoA is further metabolized in the Krebs cycle. A researcher measured the
, accumulation of acetyl-CoA in a reaction containing pyruvate and pyruvate
dehydrogenase under several different conditions
5. Which of the following best describes the cellular location where pyruvate
dehydrogenase is most likely active?
6. The maximum production rate of acetyl-CoA under condition 1 is closer to which
of the following?
7. Which of the following observations provides the best evidence that acetyl-CoA
negatively regulates pyruvate dehydrogenase activity?
8. Which of the following best explains the buildup of lactic acid in individuals with
the mutation?
✓ ~~~5. The mitochondrial matrix
6. 1 micromole/sec
7. The rate of pyruvate dehydrogenase-catalyzed reaction is slower in the presence
of a higher concentration of acetyl-CoA
8. Cells undergo fermentation because pyruvate cannot be metabolized to proceed
into the Krebs cycle
Which of the following best explains how water is able to move upward from the
roots of a plant, through its xylem in the stem, and out to the leaves?
✓ ~~~Water and the xylem are both polar. Water molecules have the ability to form
hydrogen bonds with each other and with the walls of the xylem.
