Question 1

Signals that travel to distant cells through the circulatory system are known as

Accepted Answer

A)  paracrine signals. 
B)  parasitic signals. 
C)  autocrine signals. 
D)  hormones. 
E)  responders. 
A)  paracrine signals. 
B)  parasitic signals. 
C)  autocrine signals. 
D)  hormones. 
E)  responders.

Question 2

Which molecule acts as a second messenger in the cascade by which epinephrine stimulates the activation of the enzyme glycogen phosphorylase?

Accepted Answer

A)  Adenosine 
B)  Caffeine 
C)  Citric acid 
D)  Cyclic AMP 
E)  Adenylyl cyclase 
A)  Adenosine 
B)  Caffeine 
C)  Citric acid 
D)  Cyclic AMP 
E)  Adenylyl cyclase

Question 3

The binding of a single molecule of epinephrine to a receptor can result in the activation of 1,000 molecules of glycogen phosphorylase. This result of the signaling transduction cascade is an example of the phenomenon known as _______.

Accepted Answer

The answer of The binding of a single molecule of...

Question 4

Second messengers

Accepted Answer

A)  are typically very specific in their activity. 
B)  do not amplify a signal. 
C)  have enzymatic activity. 
D)  can be derived from lipids. 
E)  All of the above 
A)  are typically very specific in their activity. 
B)  do not amplify a signal. 
C)  have enzymatic activity. 
D)  can be derived from lipids. 
E)  All of the above

Question 5

The receptor of estrogen

Accepted Answer

A)  is an ion channel receptor. 
B)  is a protein kinase receptor. 
C)  exists within the plasma membrane. 
D)  exists within the cytoplasm. 
E)  None of the above 
A)  is an ion channel receptor. 
B)  is a protein kinase receptor. 
C)  exists within the plasma membrane. 
D)  exists within the cytoplasm. 
E)  None of the above

Question 6

Hormones are chemical signals that

Accepted Answer

A)  affect adjacent cells. 
B)  work in prokaryotes. 
C)  are autocrine signals. 
D)  travel through circulatory systems. 
E)  are paracrine signals. 
A)  affect adjacent cells. 
B)  work in prokaryotes. 
C)  are autocrine signals. 
D)  travel through circulatory systems. 
E)  are paracrine signals.

Question 7

Lithium can be effective in the treatment of bipolar disorder because it

Accepted Answer

A)  opens up the lithium ion channel. 
B)  acts as a second messenger accelerating the IP3/DAG signal transduction pathway. 
C)  inhibits G protein activation of phospholipase C and inhibits synthesis of IP3. 
D)  changes the osmotic balance of cells. 
E)  acts as a neurotransmitter. 
A)  opens up the lithium ion channel. 
B)  acts as a second messenger accelerating the IP3/DAG signal transduction pathway. 
C)  inhibits G protein activation of phospholipase C and inhibits synthesis of IP3. 
D)  changes the osmotic balance of cells. 
E)  acts as a neurotransmitter.

Question 8

Which of the following statements about gap junctions is true?

Accepted Answer

A)  They generally occupy less than 5 percent of the area of the plasma membrane. 
B)  They are specialized structures that permit metabolic cooperation among the linked cells. 
C)  They occur only in plants. 
D)  They are made of G proteins. 
E)  All of the above 
A)  They generally occupy less than 5 percent of the area of the plasma membrane. 
B)  They are specialized structures that permit metabolic cooperation among the linked cells. 
C)  They occur only in plants. 
D)  They are made of G proteins. 
E)  All of the above

Question 9

The phosphorylation and change in shape of the responder in the E. coli signaling transduction pathway is a key event in signaling for which of the following reasons?

Accepted Answer

A)  The signal that originally was on the outside of the cell has been transduced to a protein that exists totally within the cell's cytoplasm. 
B)  The signal has been amplified. 
C)  The altered responder can bind to DNA and stimulate transcription of one or more genes. 
D)  Both a and c 
E)  All of the above 
A)  The signal that originally was on the outside of the cell has been transduced to a protein that exists totally within the cell's cytoplasm. 
B)  The signal has been amplified. 
C)  The altered responder can bind to DNA and stimulate transcription of one or more genes. 
D)  Both a and c 
E)  All of the above

Question 10

Which of the following are specialized cell junctions that allow neighboring cells to communicate directly?

Accepted Answer

A)  Tight junctions 
B)  Gap junctions 
C)  Desmosomes 
D)  Ion channels 
E)  G proteins 
A)  Tight junctions 
B)  Gap junctions 
C)  Desmosomes 
D)  Ion channels 
E)  G proteins

Question 11

Which of the following statements about plasmodesmata is false?

Accepted Answer

A)  Plasmodesmata are lined by the fused membranes themselves. 
B)  Plasmodesmata are larger than a gap junction channel. 
C)  The desmotubule is probably derived from the endoplasmic reticulum. 
D)  Only small metabolites and ions can move between plant cells. 
E)  Plasmodesmata are specialized for intercellular communication. 
A)  Plasmodesmata are lined by the fused membranes themselves. 
B)  Plasmodesmata are larger than a gap junction channel. 
C)  The desmotubule is probably derived from the endoplasmic reticulum. 
D)  Only small metabolites and ions can move between plant cells. 
E)  Plasmodesmata are specialized for intercellular communication.

Question 12

Caffeine

Accepted Answer

A)  is structurally related to GDP. 
B)  binds to a receptor in the brain. 
C)  causes signal transduction by itself. 
D)  is a signal. 
E)  a depressant. 
A)  is structurally related to GDP. 
B)  binds to a receptor in the brain. 
C)  causes signal transduction by itself. 
D)  is a signal. 
E)  a depressant.

Question 13

Based on your knowledge of prokaryotic and eukaryotic cell structure and function, explain how signal transduction might differ in prokaryotes and
eukaryotes?

Accepted Answer

Signal transduction in prokary

Question 14

Which of the following statements is true?

Accepted Answer

A)  Eukaryotic, but not prokaryotic, cells process information from their environment. 
B)  Prokaryotic, but not eukaryotic, cells process information from their environment. 
C)  The mere presence of a signal will cause a cell to respond to it. 
D)  Light can be a signal. 
E)  Sense organs allow cells to respond to physical signals but not chemical signals. 
A)  Eukaryotic, but not prokaryotic, cells process information from their environment. 
B)  Prokaryotic, but not eukaryotic, cells process information from their environment. 
C)  The mere presence of a signal will cause a cell to respond to it. 
D)  Light can be a signal. 
E)  Sense organs allow cells to respond to physical signals but not chemical signals.

Question 15

What is the G protein that has been found in many human bladder cancers?

Accepted Answer

A)  Acetylcholine 
B)  Rap 
C)  Ras 
D)  Rats 
E)  None of the above 
A)  Acetylcholine 
B)  Rap 
C)  Ras 
D)  Rats 
E)  None of the above

Question 16

Which of the following statements is true?

Accepted Answer

A)  Most cells are in contact with their neighbors. 
B)  Tight junctions are specialized for intercellular communication. 
C)  Desmosomes are specialized for intercellular communication. 
D)  Gap junctions are channels between adjacent cells. 
E)  All of the above 
A)  Most cells are in contact with their neighbors. 
B)  Tight junctions are specialized for intercellular communication. 
C)  Desmosomes are specialized for intercellular communication. 
D)  Gap junctions are channels between adjacent cells. 
E)  All of the above

Question 17

Plasmodesmata and gap junctions

Accepted Answer

A)  allow small molecules and ions to pass rapidly between cells. 
B)  are both membrane-lined channels. 
C)  are channels about 1 mm in diameter. 
D)  are present only once per cell. 
E)  are involved in cell recognition. 
A)  allow small molecules and ions to pass rapidly between cells. 
B)  are both membrane-lined channels. 
C)  are channels about 1 mm in diameter. 
D)  are present only once per cell. 
E)  are involved in cell recognition.

Question 18

Which of the following statements about protein kinase cascades is true?

Accepted Answer

A)  Amplification can occur at each step in the path. 
B)  Information at the plasma membrane is communicated to the nucleus. 
C)  The multiple steps allow for specificity of the process. 
D)  Different targets can produce variation in the cellular response. 
E)  All of the above 
A)  Amplification can occur at each step in the path. 
B)  Information at the plasma membrane is communicated to the nucleus. 
C)  The multiple steps allow for specificity of the process. 
D)  Different targets can produce variation in the cellular response. 
E)  All of the above

Question 19

Caffeine indirectly stimulates the signaling pathway associated with the "fight-or-flight" response normally stimulated by _______.

Accepted Answer

epinephrin

Question 20

The G protein-mediated cascade stimulated by epine­phrine results in the phosphorylation of two key enzymes. The eventual results of this phosphorylation are the _______ of glycogen synthase and the _______ of glycogen phosphorylase.

Accepted Answer

A)  stimulation; stimulation 
B)  stimulation; inhibition 
C)  inhibition; stimulation 
D)  inhibition; inhibition 
E)  inhibition; introversion 
A)  stimulation; stimulation 
B)  stimulation; inhibition 
C)  inhibition; stimulation 
D)  inhibition; inhibition 
E)  inhibition; introversion

Exam 7: Cell Signaling and Communication

Signals that travel to distant cells through the circulatory system are known as

Which molecule acts as a second messenger in the cascade by which epinephrine stimulates the activation of the enzyme glycogen phosphorylase?

The binding of a single molecule of epinephrine to a receptor can result in the activation of 1,000 molecules of glycogen phosphorylase. This result of the signaling transduction cascade is an example of the phenomenon known as _______.

Second messengers

The receptor of estrogen

Hormones are chemical signals that

Lithium can be effective in the treatment of bipolar disorder because it

Which of the following statements about gap junctions is true?

The phosphorylation and change in shape of the responder in the E. coli signaling transduction pathway is a key event in signaling for which of the following reasons?

Which of the following are specialized cell junctions that allow neighboring cells to communicate directly?

Which of the following statements about plasmodesmata is false?

Caffeine

Based on your knowledge of prokaryotic and eukaryotic cell structure and function, explain how signal transduction might differ in prokaryotes and eukaryotes?

Which of the following statements is true?

What is the G protein that has been found in many human bladder cancers?

Which of the following statements is true?

Plasmodesmata and gap junctions

Which of the following statements about protein kinase cascades is true?

Caffeine indirectly stimulates the signaling pathway associated with the "fight-or-flight" response normally stimulated by _______.

The G protein-mediated cascade stimulated by epine­phrine results in the phosphorylation of two key enzymes. The eventual results of this phosphorylation are the _______ of glycogen synthase and the _______ of glycogen phosphorylase.

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The G protein-mediated cascade stimulated by epinephrine results in the phosphorylation of two key enzymes. The eventual results of this phosphorylation are the _ of glycogen synthase and the _ of glycogen phosphorylase.