Deck 6: Cell Communication

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Question
How is paracrine signaling different from other types of signaling?

A) The signaling molecule are hormones.
B) The signaling molecules release neurotransmitters.
C) The signaling molecules are displayed on the cell surface.
D) The signaling molecules are transferred by electrical signals.
E) The signaling molecule diffused through interstitial fluid, acting on nearby cells.
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Question
A receptor on the cell surface usually has several domains. What is the function of the external domain?

A) It function is as an enzyme.
B) It attaches the receptor to the DNA.
C) It holds the receptor within the membrane.
D) It transmits the signal to the inside of the cell.
E) It is the docking site for a signaling molecule.
Question
During enzyme-linked reception, signal molecules bind to two tyrosine kinase receptors. The receptor proteins move closer together in the plasma membrane and pair, forming a(n) ____.

A) gate
B) dimer
C) pathway
D) polypeptide chain
E) protein kinase cascade
Question
Which neurotransmitter opens ligand-gated sodium channels?

A) GABA
B) cortisol
C) ecdysone
D) acetylcholine
E) brassinosteroid
Question
The outer part of a G protein receptor binds to a(n) ____, and its inner part binds to a(n) ____.

A) G protein; ion channel
B) G protein; tyrosine kinase
C) ion channel; G protein
D) signaling molecule; G protein
E) signaling molecule; tyrosine kinase
Question
How are hormones produced by endocrine glands typically transported to target cells?

A) in the blood
B) through the air
C) across a synapse
D) via direct contact
E) in interstitial fluid
Question
Most intracellular receptors are what type of protein?

A) DNA
B) steroids
C) enzymes
D) neurotransmitters
E) transcription factors
Question
Which receptor in plant cells is activated by red light?

A) rhodopsin
B) diacylglycerol
C) acetylcholine
D) phytochrome
E) cryptochrome
Question
Under which of the following situations would receptor down-regulation most likely occur?

A) The number of G proteins is too high.
B) The concentration of a hormone is too high.
C) The cell is unable to manufacture cyclic AMP.
D) The concentration of a neurotransmitter is too low.
E) The number of receptors in the plasma membrane is too low.
Question
What can happen when GABA binds to its receptor?

A) Neural signaling is inhibited.
B) Sodium ions enter the cell.
C) New signals are transmitted.
D) Muscle contraction is stimulated.
E) Enzyme-linked receptors are activated.
Question
Which list describes the correct sequence of events involved in cell signaling?

A) signal transduction, reception, signal transmission, response
B) response, signal transduction, signal transmission, reception
C) signal transmission, signal transduction, reception, response
D) reception, signal transmission, response, signal transduction
E) signal transmission, reception, signal transduction, response
Question
What type of cells must receive, relay, and respond to the information signaled?

A) GABA
B) integrins
C) target cells
D) local regulators
E) neurotransmitters
Question
Suppose that acetylcholine binds its receptor on the surface of a muscle cell. What happens next?

A) A sodium gate opens.
B) G protein is activated.
C) Tyrosine is phosphorylated.
D) Tyrosine kinase is activated.
E) A neurotransmitter crosses the synapse.
Question
Which statement about receptors is false ?

A) They are highly selective.
B) They are also called ligands.
C) They are proteins or glycoproteins.
D) They are found inside the cell and on the cell surface.
E) They are activated by binding to a signaling molecule.
Question
How are brassinosteroids different from animal steroid hormones?

A) BRs regulate only cell division.
B) BRs are enzyme-linked receptors.
C) BRs bind with intracellular receptors.
D) BRs have a histidine kinase that extends into the cell.
E) BRs bind with a protein kinase receptor in the plasma membrane.
Question
What type of chemical compound diffuses across synapses?

A) neurons
B) hormones
C) nitric oxide
D) prostaglandins
E) neurotransmitters
Question
How many times do G protein-linked receptors loop back and forth through the plasma membrane?

A) once
B) twice
C) three
D) seven
E) eleven
Question
What is typically the result of receptor up-regulation?

A) A hormone's signal is amplified.
B) The number of receptors decreases.
C) The sensitivity of a cell to a hormone decreases.
D) The number of genes that code for a receptor increases.
E) The concentration of hormone molecules in the blood increases.
Question
Which local regulator is stored in cells of the immune system and released during an allergic reaction?

A) histamine
B) nitric oxide
C) a growth factor
D) a prostaglandin
E) a neurotransmitter
Question
Typically, the gate of an ion channel remains closed until a(n) ____ binds to the receptor.

A) ligand
B) enzyme
C) G protein
D) target cell
E) first messenger
Question
During signal transduction of a G protein, the first messenger binds to the receptor, and the G protein is activated. What happens next?

A) formation of cAMP
B) cellular response
C) activation of protein kinase
D) activation of adenylyl cyclase
E) phosphorylation of the G protein
Question
What enzyme splits a membrane phospholipid into inositol trisphosphate (IP3) and diacylglycerol (DAG)?

A) phospholipase C
B) protein kinase C
C) adenylyl cyclase
D) protein kinase A
E) phosphodiesterase
Question
What type of protein can transduce a signal in two directions?

A) integrins
B) G proteins
C) Ras proteins
D) scaffold proteins
E) phosphorylated proteins
Question
The hydrolysis of GTP to GDP deactivates the ____.

A) cAMP
B) G protein
C) Ras protein
D) ligand-gated channel
E) protein kinase pathway
Question
In the cAMP signal transduction pathway, a protein kinase is activated. What happens next/

A) G protein is activated.
B) GDP is replaced by GTP.
C) cAMP is converted to ATP.
D) Adenylyl cyclase is activated.
E) The protein kinase activates a cellular response.
Question
In the phospholipase C signal transduction pathway, which two second messengers are produced?

A) IP3 and DAG
B) PIP2 and IP3
C) cAMP and IP3
D) phospholipase C and protein kinase A
E) phospholipase C and G protein
Question
Which is a major group of enzyme-linked receptors?

A) G proteins
B) ion channels
C) tyrosine kinases
D) phospholipases
E) adenylyl cyclases
Question
During signal transduction involving G protein and cAMP, what do protein kinases add to target proteins?

A) enzyme
B) substrates
C) calmodulin
D) calcium ions
E) phosphate groups
Question
Phosphodiesterase catalyzes the conversion of:

A) IP3 to PIP2.
B) GDP to GTP.
C) cAMP to AMP.
D) calcium to calcium-calmodulin.
E) a protein to a phosphorylated protein.
Question
Which statement about G protein is false ?

A) Its subunits can separate.
B) One subunit is a GTPase.
C) One subunit binds GTP.
D) One subunit binds GDP.
E) One subunit binds ATP.
Question
Phospholipase C catalyzes the reaction in which:

A) PIP2 is split.
B) IP3 is converted to DAG.
C) a protein kinase is activated.
D) DAG is converted to PIP2.
E) calcium ions are released from the ER.
Question
What is calmodulin?

A) a hormone
B) a phosphatase
C) a phospholipase
D) a protein kinase
E) a calcium-binding protein
Question
What activates protein kinase C?

A) IP3
B) DAG
C) cAMP
D) PIP2
E) calcium ions
Question
Where are calcium ions stored before a signaling pathway releases them into the cytosol?

A) nucleus
B) ribosome
C) lysosome
D) plasma membrane
E) endoplasmic reticulum
Question
Scaffold proteins ensure that signals are relayed ____.

A) slowly
B) efficiently
C) inaccurately
D) methodically
E) simultaneously
Question
Which is an example of a second messenger?

A) protein kinase A
B) an ion channel
C) cyclic AMP
D) GABA
E) insulin
Question
Many intracellular receptors are transcription factors; when activated, they activate or repress specific _____ .

A) genes
B) neurons
C) kinases
D) enyzmes
E) ribosomes
Question
Adenylyl cyclase catalyzes the reaction in which:

A) PIP2 is split.
B) ATP is converted to cAMP.
C) GTP is converted to GDP.
D) a protein is phosphorylated.
E) calcium ions bind calmodulin.
Question
In the IP3 pathway, what is the function of IP3?

A) Activate protein kinase C.
B) Activate phospholipase C.
C) Phosphorylate a protein.
D) Bind calcium channels in the ER.
E) Activate adenylyl cyclase.
Question
Which molecule is a first messenger but not a second messenger?

A) G protein
B) cyclic AMP
C) acetylcholine
D) protein kinase
E) adenylyl cyclase
Question
Which statement about Ras proteins is false ?

A) They are G proteins.
B) They include MAP kinases.
C) They are active when bound to GTP.
D) They are inactivated when phosphorylated.
E) They are activated by tyrosine kinase receptors.
Question
When a signaling molecule binds to a G protein linked receptor, the ligand-receptor complex associates with GDP protein and causes GDP to be replaced by GTP.
__________________
Question
Why is it important for cells to be able to communicate with one another? List the main steps involved in cell signaling.
Question
You conduct an experiment in which you inactivate Ras proteins in fibroblast cells. Which of the following is the most immediate consequence of this procedure?

A) The fibroblasts divide uncontrollably.
B) The fibroblasts synthesize excess DAG.
C) The fibroblasts synthesize excess G protein.
D) The fibroblasts no longer respond to calmodulin.
E) The fibroblasts no longer synthesize DNA in response to growth factors.
Question
In what part of the cell does a polar signaling molecule bind its receptor? A nonpolar signaling molecule? Explain your reasoning.
Question
The main signaling cascade for cell division and differentiation is the ____ cascade.

A) cAMP
B) MAP kinase
C) phosphoinositol
D) phospholipase C
E) calcium-calmodulin
Question
Compare and contrast local regulators, neurotransmitters, and hormones.
Question
When signal molecules bind to two tyrosine kinase receptors, the receptors move closer to each other and form a monomer . __________________
Question
The outer part of the enzyme linked receptor has a binding site for a signaling molecule, and the part of the receptor that extends into the cytosol has a binding site for a specific G protein.
__________________
Question
Choanoflagellates have been important for the study of cell communication evolution because choanoflagellates have:

A) protein kinases similar to those in animals.
B) G proteins different from those in prokaryotes.
C) signaling molecules similar to those of other protists.
D) signal transduction pathways unlike those in other bacteria.
E) signal transduction pathways that interfere with the cells they infect.
Question
What is the difference between a first messenger and a second messenger? Give an example of each.
Question
What is calmodulin, and what role does it play in signal transduction?
Question
When an enzyme linked receptor is activated, a conformational change activates the extracellular kinases.
__________________
Question
Ion channels are found in the plasma membranes of neurons and muscle cells.
__________________
Question
What is the process in which one activated receptor can give rise to thousands of final products?

A) signal transcription
B) signal transmission
C) signal transduction
D) signal termination
E) signal amplification
Question
What happens when Ras proteins become stuck in their "on" state?

A) Cellar responses are slowed.
B) Additional ions are catalyzed.
C) There is unregulated cell division.
D) There is an increase in protein synthesis.
E) Ligand-gated channels close off the membrane.
Question
Which MAP kinase was found to be a signaling molecule for oocyte maturation in mice?

A) Mek and Raf
B) Ras 1 and ERK 2
C) Raf 1 and Raf 2
D) Mek and ERK2
E) ERK 1 and ERK 2
Question
Insulin stimulates cells to take in glucose by facilitated diffusion, so insulin receptor-down regulation increases the ability of cells to take in glucose.
__________________
Question
When food is abundant , the cellular slime mold secretes cAMP into the environment to signal the formation of a multicellular slug-shaped colony.
__________________
Question
Which MAP protein kinase is the last to be activated in the MAP kinase pathway?

A) Ras
B) Raf
C) ERK
D) Mek
E) tyrosine
Question
Match between columns
Phosphate comes from ATP.
Enzyme linked receptor
Phosphate comes from ATP.
Ion channel linked receptor
Phosphate comes from ATP.
G protein linked receptor
Sodium ions enter the cell.
Enzyme linked receptor
Sodium ions enter the cell.
Ion channel linked receptor
Sodium ions enter the cell.
G protein linked receptor
GDP is replaced with GTP.
Enzyme linked receptor
GDP is replaced with GTP.
Ion channel linked receptor
GDP is replaced with GTP.
G protein linked receptor
Enzyme linked receptor
Ion channel linked receptor
G protein linked receptor
Enzyme linked receptor
Ion channel linked receptor
G protein linked receptor
Question
Compare and contrast the structure and function of ion channel-linked receptors, G protein-linked receptors, and enzyme-linked receptors. In general, how do they differ from intracellular receptors?
Question
Injecting fibroblasts with anti-Ras antibodies that inactivate Ras proteins increases cell division response to growth factors.
__________________
Question
Give some examples showing how cells respond to signals. How are signals terminated?
Question
Barbiturates and benzodiazepine drugs bind to GABA receptors to open chloride channels, inhibit neural impulse, and induce tranquility.
__________________
Question
Scaffold proteins organize groups of intracellular signaling kinases into signaling complexes.
__________________
Question
Explain the differences between receptor up-regulation and down-regulation including the conditions under which a cell would use one rather than the other.
Question
What is meant by signal amplification? Provide two examples.
Question
Compare and contrast the signal transduction pathway involving cAMP with that involving phospholipids.
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Deck 6: Cell Communication
1
How is paracrine signaling different from other types of signaling?

A) The signaling molecule are hormones.
B) The signaling molecules release neurotransmitters.
C) The signaling molecules are displayed on the cell surface.
D) The signaling molecules are transferred by electrical signals.
E) The signaling molecule diffused through interstitial fluid, acting on nearby cells.
E
2
A receptor on the cell surface usually has several domains. What is the function of the external domain?

A) It function is as an enzyme.
B) It attaches the receptor to the DNA.
C) It holds the receptor within the membrane.
D) It transmits the signal to the inside of the cell.
E) It is the docking site for a signaling molecule.
E
3
During enzyme-linked reception, signal molecules bind to two tyrosine kinase receptors. The receptor proteins move closer together in the plasma membrane and pair, forming a(n) ____.

A) gate
B) dimer
C) pathway
D) polypeptide chain
E) protein kinase cascade
B
4
Which neurotransmitter opens ligand-gated sodium channels?

A) GABA
B) cortisol
C) ecdysone
D) acetylcholine
E) brassinosteroid
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Unlock for access to all 69 flashcards in this deck.
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k this deck
5
The outer part of a G protein receptor binds to a(n) ____, and its inner part binds to a(n) ____.

A) G protein; ion channel
B) G protein; tyrosine kinase
C) ion channel; G protein
D) signaling molecule; G protein
E) signaling molecule; tyrosine kinase
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Unlock for access to all 69 flashcards in this deck.
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k this deck
6
How are hormones produced by endocrine glands typically transported to target cells?

A) in the blood
B) through the air
C) across a synapse
D) via direct contact
E) in interstitial fluid
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
7
Most intracellular receptors are what type of protein?

A) DNA
B) steroids
C) enzymes
D) neurotransmitters
E) transcription factors
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
8
Which receptor in plant cells is activated by red light?

A) rhodopsin
B) diacylglycerol
C) acetylcholine
D) phytochrome
E) cryptochrome
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
9
Under which of the following situations would receptor down-regulation most likely occur?

A) The number of G proteins is too high.
B) The concentration of a hormone is too high.
C) The cell is unable to manufacture cyclic AMP.
D) The concentration of a neurotransmitter is too low.
E) The number of receptors in the plasma membrane is too low.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
10
What can happen when GABA binds to its receptor?

A) Neural signaling is inhibited.
B) Sodium ions enter the cell.
C) New signals are transmitted.
D) Muscle contraction is stimulated.
E) Enzyme-linked receptors are activated.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
11
Which list describes the correct sequence of events involved in cell signaling?

A) signal transduction, reception, signal transmission, response
B) response, signal transduction, signal transmission, reception
C) signal transmission, signal transduction, reception, response
D) reception, signal transmission, response, signal transduction
E) signal transmission, reception, signal transduction, response
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k this deck
12
What type of cells must receive, relay, and respond to the information signaled?

A) GABA
B) integrins
C) target cells
D) local regulators
E) neurotransmitters
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
13
Suppose that acetylcholine binds its receptor on the surface of a muscle cell. What happens next?

A) A sodium gate opens.
B) G protein is activated.
C) Tyrosine is phosphorylated.
D) Tyrosine kinase is activated.
E) A neurotransmitter crosses the synapse.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
14
Which statement about receptors is false ?

A) They are highly selective.
B) They are also called ligands.
C) They are proteins or glycoproteins.
D) They are found inside the cell and on the cell surface.
E) They are activated by binding to a signaling molecule.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
15
How are brassinosteroids different from animal steroid hormones?

A) BRs regulate only cell division.
B) BRs are enzyme-linked receptors.
C) BRs bind with intracellular receptors.
D) BRs have a histidine kinase that extends into the cell.
E) BRs bind with a protein kinase receptor in the plasma membrane.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
16
What type of chemical compound diffuses across synapses?

A) neurons
B) hormones
C) nitric oxide
D) prostaglandins
E) neurotransmitters
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
17
How many times do G protein-linked receptors loop back and forth through the plasma membrane?

A) once
B) twice
C) three
D) seven
E) eleven
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Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
18
What is typically the result of receptor up-regulation?

A) A hormone's signal is amplified.
B) The number of receptors decreases.
C) The sensitivity of a cell to a hormone decreases.
D) The number of genes that code for a receptor increases.
E) The concentration of hormone molecules in the blood increases.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
19
Which local regulator is stored in cells of the immune system and released during an allergic reaction?

A) histamine
B) nitric oxide
C) a growth factor
D) a prostaglandin
E) a neurotransmitter
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
20
Typically, the gate of an ion channel remains closed until a(n) ____ binds to the receptor.

A) ligand
B) enzyme
C) G protein
D) target cell
E) first messenger
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21
During signal transduction of a G protein, the first messenger binds to the receptor, and the G protein is activated. What happens next?

A) formation of cAMP
B) cellular response
C) activation of protein kinase
D) activation of adenylyl cyclase
E) phosphorylation of the G protein
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22
What enzyme splits a membrane phospholipid into inositol trisphosphate (IP3) and diacylglycerol (DAG)?

A) phospholipase C
B) protein kinase C
C) adenylyl cyclase
D) protein kinase A
E) phosphodiesterase
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Unlock Deck
k this deck
23
What type of protein can transduce a signal in two directions?

A) integrins
B) G proteins
C) Ras proteins
D) scaffold proteins
E) phosphorylated proteins
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24
The hydrolysis of GTP to GDP deactivates the ____.

A) cAMP
B) G protein
C) Ras protein
D) ligand-gated channel
E) protein kinase pathway
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25
In the cAMP signal transduction pathway, a protein kinase is activated. What happens next/

A) G protein is activated.
B) GDP is replaced by GTP.
C) cAMP is converted to ATP.
D) Adenylyl cyclase is activated.
E) The protein kinase activates a cellular response.
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26
In the phospholipase C signal transduction pathway, which two second messengers are produced?

A) IP3 and DAG
B) PIP2 and IP3
C) cAMP and IP3
D) phospholipase C and protein kinase A
E) phospholipase C and G protein
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k this deck
27
Which is a major group of enzyme-linked receptors?

A) G proteins
B) ion channels
C) tyrosine kinases
D) phospholipases
E) adenylyl cyclases
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Unlock Deck
k this deck
28
During signal transduction involving G protein and cAMP, what do protein kinases add to target proteins?

A) enzyme
B) substrates
C) calmodulin
D) calcium ions
E) phosphate groups
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29
Phosphodiesterase catalyzes the conversion of:

A) IP3 to PIP2.
B) GDP to GTP.
C) cAMP to AMP.
D) calcium to calcium-calmodulin.
E) a protein to a phosphorylated protein.
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30
Which statement about G protein is false ?

A) Its subunits can separate.
B) One subunit is a GTPase.
C) One subunit binds GTP.
D) One subunit binds GDP.
E) One subunit binds ATP.
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Unlock Deck
k this deck
31
Phospholipase C catalyzes the reaction in which:

A) PIP2 is split.
B) IP3 is converted to DAG.
C) a protein kinase is activated.
D) DAG is converted to PIP2.
E) calcium ions are released from the ER.
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32
What is calmodulin?

A) a hormone
B) a phosphatase
C) a phospholipase
D) a protein kinase
E) a calcium-binding protein
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k this deck
33
What activates protein kinase C?

A) IP3
B) DAG
C) cAMP
D) PIP2
E) calcium ions
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34
Where are calcium ions stored before a signaling pathway releases them into the cytosol?

A) nucleus
B) ribosome
C) lysosome
D) plasma membrane
E) endoplasmic reticulum
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k this deck
35
Scaffold proteins ensure that signals are relayed ____.

A) slowly
B) efficiently
C) inaccurately
D) methodically
E) simultaneously
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Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
36
Which is an example of a second messenger?

A) protein kinase A
B) an ion channel
C) cyclic AMP
D) GABA
E) insulin
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k this deck
37
Many intracellular receptors are transcription factors; when activated, they activate or repress specific _____ .

A) genes
B) neurons
C) kinases
D) enyzmes
E) ribosomes
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
38
Adenylyl cyclase catalyzes the reaction in which:

A) PIP2 is split.
B) ATP is converted to cAMP.
C) GTP is converted to GDP.
D) a protein is phosphorylated.
E) calcium ions bind calmodulin.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
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39
In the IP3 pathway, what is the function of IP3?

A) Activate protein kinase C.
B) Activate phospholipase C.
C) Phosphorylate a protein.
D) Bind calcium channels in the ER.
E) Activate adenylyl cyclase.
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Unlock for access to all 69 flashcards in this deck.
Unlock Deck
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40
Which molecule is a first messenger but not a second messenger?

A) G protein
B) cyclic AMP
C) acetylcholine
D) protein kinase
E) adenylyl cyclase
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Unlock Deck
k this deck
41
Which statement about Ras proteins is false ?

A) They are G proteins.
B) They include MAP kinases.
C) They are active when bound to GTP.
D) They are inactivated when phosphorylated.
E) They are activated by tyrosine kinase receptors.
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Unlock Deck
k this deck
42
When a signaling molecule binds to a G protein linked receptor, the ligand-receptor complex associates with GDP protein and causes GDP to be replaced by GTP.
__________________
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43
Why is it important for cells to be able to communicate with one another? List the main steps involved in cell signaling.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
44
You conduct an experiment in which you inactivate Ras proteins in fibroblast cells. Which of the following is the most immediate consequence of this procedure?

A) The fibroblasts divide uncontrollably.
B) The fibroblasts synthesize excess DAG.
C) The fibroblasts synthesize excess G protein.
D) The fibroblasts no longer respond to calmodulin.
E) The fibroblasts no longer synthesize DNA in response to growth factors.
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
45
In what part of the cell does a polar signaling molecule bind its receptor? A nonpolar signaling molecule? Explain your reasoning.
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Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
46
The main signaling cascade for cell division and differentiation is the ____ cascade.

A) cAMP
B) MAP kinase
C) phosphoinositol
D) phospholipase C
E) calcium-calmodulin
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
47
Compare and contrast local regulators, neurotransmitters, and hormones.
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k this deck
48
When signal molecules bind to two tyrosine kinase receptors, the receptors move closer to each other and form a monomer . __________________
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49
The outer part of the enzyme linked receptor has a binding site for a signaling molecule, and the part of the receptor that extends into the cytosol has a binding site for a specific G protein.
__________________
Unlock Deck
Unlock for access to all 69 flashcards in this deck.
Unlock Deck
k this deck
50
Choanoflagellates have been important for the study of cell communication evolution because choanoflagellates have:

A) protein kinases similar to those in animals.
B) G proteins different from those in prokaryotes.
C) signaling molecules similar to those of other protists.
D) signal transduction pathways unlike those in other bacteria.
E) signal transduction pathways that interfere with the cells they infect.
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51
What is the difference between a first messenger and a second messenger? Give an example of each.
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52
What is calmodulin, and what role does it play in signal transduction?
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53
When an enzyme linked receptor is activated, a conformational change activates the extracellular kinases.
__________________
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54
Ion channels are found in the plasma membranes of neurons and muscle cells.
__________________
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55
What is the process in which one activated receptor can give rise to thousands of final products?

A) signal transcription
B) signal transmission
C) signal transduction
D) signal termination
E) signal amplification
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56
What happens when Ras proteins become stuck in their "on" state?

A) Cellar responses are slowed.
B) Additional ions are catalyzed.
C) There is unregulated cell division.
D) There is an increase in protein synthesis.
E) Ligand-gated channels close off the membrane.
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57
Which MAP kinase was found to be a signaling molecule for oocyte maturation in mice?

A) Mek and Raf
B) Ras 1 and ERK 2
C) Raf 1 and Raf 2
D) Mek and ERK2
E) ERK 1 and ERK 2
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58
Insulin stimulates cells to take in glucose by facilitated diffusion, so insulin receptor-down regulation increases the ability of cells to take in glucose.
__________________
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59
When food is abundant , the cellular slime mold secretes cAMP into the environment to signal the formation of a multicellular slug-shaped colony.
__________________
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60
Which MAP protein kinase is the last to be activated in the MAP kinase pathway?

A) Ras
B) Raf
C) ERK
D) Mek
E) tyrosine
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61
Match between columns
Phosphate comes from ATP.
Enzyme linked receptor
Phosphate comes from ATP.
Ion channel linked receptor
Phosphate comes from ATP.
G protein linked receptor
Sodium ions enter the cell.
Enzyme linked receptor
Sodium ions enter the cell.
Ion channel linked receptor
Sodium ions enter the cell.
G protein linked receptor
GDP is replaced with GTP.
Enzyme linked receptor
GDP is replaced with GTP.
Ion channel linked receptor
GDP is replaced with GTP.
G protein linked receptor
Enzyme linked receptor
Ion channel linked receptor
G protein linked receptor
Enzyme linked receptor
Ion channel linked receptor
G protein linked receptor
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62
Compare and contrast the structure and function of ion channel-linked receptors, G protein-linked receptors, and enzyme-linked receptors. In general, how do they differ from intracellular receptors?
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63
Injecting fibroblasts with anti-Ras antibodies that inactivate Ras proteins increases cell division response to growth factors.
__________________
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64
Give some examples showing how cells respond to signals. How are signals terminated?
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65
Barbiturates and benzodiazepine drugs bind to GABA receptors to open chloride channels, inhibit neural impulse, and induce tranquility.
__________________
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66
Scaffold proteins organize groups of intracellular signaling kinases into signaling complexes.
__________________
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67
Explain the differences between receptor up-regulation and down-regulation including the conditions under which a cell would use one rather than the other.
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68
What is meant by signal amplification? Provide two examples.
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69
Compare and contrast the signal transduction pathway involving cAMP with that involving phospholipids.
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