AP BIOLOGY UNIT 4 ACTUAL EXAM
UPDATE THIS YEAR
QUESTIONA hydrophilic peptide hormone is produced in the anterior pituitary gland located at
the base of the brain. The hormone targets specific cells in many parts of the body.
Which of the following best explains a possible mechanism that would enable the hormone to
efficiently reach all of the target cells in the body? C - answer-The hormone is released into the
bloodstream where it can be transported to all cells with the correct receptors. C
QUESTIONG proteins are a family of receptor proteins that are involved in transmitting signals
from outside a cell to inside a cell. When a signaling molecule binds to a G protein, the G
protein is activated. The G protein then activates an enzyme that produces a second messenger
called cAMP.
Which of the following describes a critical role of cAMP during the transduction stage of a G
protein signal transduction pathway? D - answer-cAMP results in the activation of an enzyme
that amplifies the signal by acting on many substrate molecules. D
Which of the following best describes the role of cell-to-cell communication during a response
to an invasion of antigens? A - answer-Chemicals that are secreted from antigen-presenting cells
then activate helper T cells. A
QUESTIONAdjacent plant cells have narrow channels called plasmodesmata that pass through
the cell walls of the connected cells and allow a cytoplasmic connection between the cells.
Which of the following statements best describes a primary function of plasmodesmata? B -
answer-They allow the movement of molecules from one cell to another, enabling
communication between cells. B
,QUESTIONWhich of the following best describes the component that metformin represents in a
signal transduction pathway that regulates glucose production in the liver? B - answer-It is a
ligand that activates the signal transduction pathway of the activation of AMPK. B
QUESTIONWhich of the following steps in a signaling pathway typically occurs first once a
chemical messenger reaches a target cell? C - answer-A ligand binds to a receptor. C
QUESTIONDuring a fight-or-flight response, epinephrine is released into the body's circulatory
system and transported throughout the body. Some cells exhibit a response to the epinephrine
while other cells do not.
Which of the following justifies the claim that differences in components of cell signaling
pathways explain the different responses to epinephrine? A - answer-Cell signaling depends on
the ability to detect a signal molecule. Not all cells have receptors for epinephrine. Only cells
with such receptors are capable of responding. A
QUESTIONSignal transduction may result in changes in gene expression and cell function, which
may alter phenotype in an embryo. An example is the expression of the SRY gene, which
triggers the male sexual development pathway in mammals. This gene is found on the Y
chromosome.
Which statement provides the evidence to justify the claim that signal transduction may result
in an altered phenotype? B - answer-If the SRY gene is absent or nonfunctional, the embryo will
exhibit female sexual development. B
QUESTIONWhich of the following statements best justifies the claim that changes in the
expression of ced−9 in C. elegans can affect regulation of apoptosis in the cell? A - answer-An
experiment showed that a mutation in the ced−9 gene led to excessive cell death in C. elegans.
A
QUESTION[figure 1. A simplified model of the insulin receptor- signaling pathway]
, Which of the following statements best predicts the effect of a loss of function of the insulin
receptor's intracellular domain? B - answer-The storage of GLUT4 in vesicles inside the cell will
increase. B
QUESTION[figure 1. GRAPH, Blood glucose fluctuations of an individual]
Which of the following best predicts what will happen to the blood glucose level if the person
has another meal at 5 p.m? B - answer-Immediately after the meal, the blood glucose level will
increase, and then insulin will be secreted to counter the increase. B
QUESTION[figure 1. Simplified model of clotting cascade]
Warfarin is a drug used to treat certain blood clots. Warfarin blocks the formation of the active
form of vitamin K-dependent clotting factors. Based on the model, which of the following best
predicts the effects of warfarin on a patient? D - answer-Factor X will not be activated, which
will prevent thrombin from forming. D
QUESTION[figure 1. Typical life cycle of a eukaryotic cell]
Based on Table 1, what percent of the life cycle of yeast cells is spent in DNA replication? C -
answer-25 percent C
QUESTION[figure 1. BAR GRAPH Mean cell doubling times for the growing root tips of Zea mays
seedlings planted in loose or compact sand]
Based on the sample means, which of the following conclusions about the cells in the growing
root tips of Zea mays seedlings is best supported by the results of the experiment? D - answer-
UPDATE THIS YEAR
QUESTIONA hydrophilic peptide hormone is produced in the anterior pituitary gland located at
the base of the brain. The hormone targets specific cells in many parts of the body.
Which of the following best explains a possible mechanism that would enable the hormone to
efficiently reach all of the target cells in the body? C - answer-The hormone is released into the
bloodstream where it can be transported to all cells with the correct receptors. C
QUESTIONG proteins are a family of receptor proteins that are involved in transmitting signals
from outside a cell to inside a cell. When a signaling molecule binds to a G protein, the G
protein is activated. The G protein then activates an enzyme that produces a second messenger
called cAMP.
Which of the following describes a critical role of cAMP during the transduction stage of a G
protein signal transduction pathway? D - answer-cAMP results in the activation of an enzyme
that amplifies the signal by acting on many substrate molecules. D
Which of the following best describes the role of cell-to-cell communication during a response
to an invasion of antigens? A - answer-Chemicals that are secreted from antigen-presenting cells
then activate helper T cells. A
QUESTIONAdjacent plant cells have narrow channels called plasmodesmata that pass through
the cell walls of the connected cells and allow a cytoplasmic connection between the cells.
Which of the following statements best describes a primary function of plasmodesmata? B -
answer-They allow the movement of molecules from one cell to another, enabling
communication between cells. B
,QUESTIONWhich of the following best describes the component that metformin represents in a
signal transduction pathway that regulates glucose production in the liver? B - answer-It is a
ligand that activates the signal transduction pathway of the activation of AMPK. B
QUESTIONWhich of the following steps in a signaling pathway typically occurs first once a
chemical messenger reaches a target cell? C - answer-A ligand binds to a receptor. C
QUESTIONDuring a fight-or-flight response, epinephrine is released into the body's circulatory
system and transported throughout the body. Some cells exhibit a response to the epinephrine
while other cells do not.
Which of the following justifies the claim that differences in components of cell signaling
pathways explain the different responses to epinephrine? A - answer-Cell signaling depends on
the ability to detect a signal molecule. Not all cells have receptors for epinephrine. Only cells
with such receptors are capable of responding. A
QUESTIONSignal transduction may result in changes in gene expression and cell function, which
may alter phenotype in an embryo. An example is the expression of the SRY gene, which
triggers the male sexual development pathway in mammals. This gene is found on the Y
chromosome.
Which statement provides the evidence to justify the claim that signal transduction may result
in an altered phenotype? B - answer-If the SRY gene is absent or nonfunctional, the embryo will
exhibit female sexual development. B
QUESTIONWhich of the following statements best justifies the claim that changes in the
expression of ced−9 in C. elegans can affect regulation of apoptosis in the cell? A - answer-An
experiment showed that a mutation in the ced−9 gene led to excessive cell death in C. elegans.
A
QUESTION[figure 1. A simplified model of the insulin receptor- signaling pathway]
, Which of the following statements best predicts the effect of a loss of function of the insulin
receptor's intracellular domain? B - answer-The storage of GLUT4 in vesicles inside the cell will
increase. B
QUESTION[figure 1. GRAPH, Blood glucose fluctuations of an individual]
Which of the following best predicts what will happen to the blood glucose level if the person
has another meal at 5 p.m? B - answer-Immediately after the meal, the blood glucose level will
increase, and then insulin will be secreted to counter the increase. B
QUESTION[figure 1. Simplified model of clotting cascade]
Warfarin is a drug used to treat certain blood clots. Warfarin blocks the formation of the active
form of vitamin K-dependent clotting factors. Based on the model, which of the following best
predicts the effects of warfarin on a patient? D - answer-Factor X will not be activated, which
will prevent thrombin from forming. D
QUESTION[figure 1. Typical life cycle of a eukaryotic cell]
Based on Table 1, what percent of the life cycle of yeast cells is spent in DNA replication? C -
answer-25 percent C
QUESTION[figure 1. BAR GRAPH Mean cell doubling times for the growing root tips of Zea mays
seedlings planted in loose or compact sand]
Based on the sample means, which of the following conclusions about the cells in the growing
root tips of Zea mays seedlings is best supported by the results of the experiment? D - answer-
