Question 1

What second messenger most directly causes calcium ions to be released from intracellular stores?

Accepted Answer

A) Diacylglycerol 
B) Adenylyl cyclase 
C) inositol trisphosphate 
D) Phospholipase A 
E) Phospholipase C 
A) Diacylglycerol 
B) Adenylyl cyclase 
C) inositol trisphosphate 
D) Phospholipase A 
E) Phospholipase C

Question 2

Activated calmodulin functions to activate or inactivate cytosolic enzymes.

Accepted Answer

A) True 
 B)False

Question 3

Some glucose transport proteins can also bind fructose,another six-carbon monosaccharide,but not lycine,an amino acid,because transport proteins exhibit ________ for their ligands.

Accepted Answer

A) saturation 
B) competition 
C) affinity 
D) affiliation 
E) specificity 
A) saturation 
B) competition 
C) affinity 
D) affiliation 
E) specificity

Question 4

Aspirin and other nonsteroidal anti-inflammatory drugs are more specific in their effects on eicosanoid synthesis than are steroidal anti-inflammatory drugs.

Accepted Answer

A) True 
 B)False

Question 5

Researchers have found that enkephalin receptors are upregulated in cocaine addicts when compared to non-users.It is likely that the action of cocaine

Accepted Answer

A) increases enkephalin in the brain. 
B) decreases enkephalin in the brain. 
C) increases enkephalin's affinity for its receptor. 
D) is an agonist to the enkephalin receptor. 
A) increases enkephalin in the brain. 
B) decreases enkephalin in the brain. 
C) increases enkephalin's affinity for its receptor. 
D) is an agonist to the enkephalin receptor.

Question 6

Second messengers

Accepted Answer

A) are necessary for all receptor signal transduction mechanisms. 
B) act in the cell cytoplasm. 
C) only function as intercellular messengers. 
D) always function to activate enzymes. 
E) are always proteins. 
A) are necessary for all receptor signal transduction mechanisms. 
B) act in the cell cytoplasm. 
C) only function as intercellular messengers. 
D) always function to activate enzymes. 
E) are always proteins.

Question 7

First messengers may bind to a membrane receptor that is an ion channel,which promotes a change in membrane polarity.

Accepted Answer

A) True 
 B)False

Question 8

The enzyme that catalyzes the production of cAMP from ATP is phosphodiesterase.

Accepted Answer

A) True 
 B)False

Question 9

In which situation would an injected drug be the most effective agonist for an endogenous chemical messenger?

Accepted Answer

A) The drug has a lower affinity for the messenger's receptors than the messenger does. 
B) The drug achieves 50% saturation of the messenger's receptors at a lower concentration than that required by the messenger. 
C) The drug does not couple to the binding site of the messenger's receptor. 
D) The drug binds to an alternate binding site on the protein receptor and reduces its affinity for the endogenous chemical messenger. 
A) The drug has a lower affinity for the messenger's receptors than the messenger does. 
B) The drug achieves 50% saturation of the messenger's receptors at a lower concentration than that required by the messenger. 
C) The drug does not couple to the binding site of the messenger's receptor. 
D) The drug binds to an alternate binding site on the protein receptor and reduces its affinity for the endogenous chemical messenger.

Question 10

Cyclic AMP activates allosteric proteins.

Accepted Answer

A) True 
 B)False

Question 11

Which of the following are ways in which binding of a chemical messenger with a cell's receptor can bring about a cellular response?

Accepted Answer

A) Opening or closing of specific ionic channels in the plasma membrane 
B) Activation of an intracellular second-messenger system 
C) Promoting or inhibiting the transcription of genes that code for the synthesis of cellular proteins 
D) Activating or inhibiting intracellular enzymes 
E) All of the choices are correct. 
A) Opening or closing of specific ionic channels in the plasma membrane 
B) Activation of an intracellular second-messenger system 
C) Promoting or inhibiting the transcription of genes that code for the synthesis of cellular proteins 
D) Activating or inhibiting intracellular enzymes 
E) All of the choices are correct.

Question 12

Which of the following statements is TRUE?

Accepted Answer

A) Phosphorylation by protein kinases can stimulate or inhibit the activity of effector proteins. 
B) Ca²⁺ is not a second messenger. 
C) Phosphodiesterase converts GMP into cGMP 
D) Conversion of ATP to cAMP is a phosphorylation reaction. 
E) Phospholipase C converts ATP to cAMP. 
A) Phosphorylation by protein kinases can stimulate or inhibit the activity of effector proteins. 
B) Ca²⁺ is not a second messenger. 
C) Phosphodiesterase converts GMP into cGMP 
D) Conversion of ATP to cAMP is a phosphorylation reaction. 
E) Phospholipase C converts ATP to cAMP.

Question 13

Competition for receptors is strictly a pharmacological phenomenon,since naturally occurring chemical messengers do not compete with each other for the same receptor site.

Accepted Answer

A) True 
 B)False

Question 14

Which of the following is known to be a second messenger?

Accepted Answer

A) Diacylglycerol 
B) Phospholipase C 
C) ATP 
D) Adenylyl cyclase 
E) Epinephrine 
A) Diacylglycerol 
B) Phospholipase C 
C) ATP 
D) Adenylyl cyclase 
E) Epinephrine

Question 15

The process whereby repeated exposure to a hormone can cause a decrease in the number of receptors for that hormone is called

Accepted Answer

A) competition. 
B) inhibition. 
C) down-regulation. 
D) antagonism. 
E) saturation. 
A) competition. 
B) inhibition. 
C) down-regulation. 
D) antagonism. 
E) saturation.

Question 16

Two cell types having the same type of receptor for a chemical messenger will always respond to that messenger in the same way.

Accepted Answer

A) True 
 B)False

What second messenger most directly causes calcium ions to be released from intracellular stores?

Activated calmodulin functions to activate or inactivate cytosolic enzymes.

Some glucose transport proteins can also bind fructose,another six-carbon monosaccharide,but not lycine,an amino acid,because transport proteins exhibit ________ for their ligands.

Aspirin and other nonsteroidal anti-inflammatory drugs are more specific in their effects on eicosanoid synthesis than are steroidal anti-inflammatory drugs.

Researchers have found that enkephalin receptors are upregulated in cocaine addicts when compared to non-users.It is likely that the action of cocaine

Second messengers

First messengers may bind to a membrane receptor that is an ion channel,which promotes a change in membrane polarity.

The enzyme that catalyzes the production of cAMP from ATP is phosphodiesterase.

In which situation would an injected drug be the most effective agonist for an endogenous chemical messenger?

Cyclic AMP activates allosteric proteins.

Which of the following are ways in which binding of a chemical messenger with a cell's receptor can bring about a cellular response?

Which of the following statements is TRUE?

Competition for receptors is strictly a pharmacological phenomenon,since naturally occurring chemical messengers do not compete with each other for the same receptor site.

Which of the following is known to be a second messenger?

The process whereby repeated exposure to a hormone can cause a decrease in the number of receptors for that hormone is called

Two cell types having the same type of receptor for a chemical messenger will always respond to that messenger in the same way.

Homeostasis: A Framework for Human Physiology

Chemical Composition of the Body and Its Relation to Physiology

Cellular Structure, Proteins, and Metabolic Pathways

Movement of Solutes and Water Across Cell Membranes

Neuronal Signaling and the Structure of the Nervous System

Sensory Physiology

Consciousness, the Brain, and Behavior

Muscle

Control Body Movement

The Endocrine System

Cardiovascular Physiology

Respiratory Physiology

The Kidneys and Regulation of Water and Inorganic Ions

The Digestion and Absorption of Food

Regulation of Organic Metabolism and Energy Balance

Reproduction

The Immune System

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Exam 5: Cell Signalling in Physiology

What second messenger most directly causes calcium ions to be released from intracellular stores?

Activated calmodulin functions to activate or inactivate cytosolic enzymes.

Some glucose transport proteins can also bind fructose,another six-carbon monosaccharide,but not lycine,an amino acid,because transport proteins exhibit ________ for their ligands.

Aspirin and other nonsteroidal anti-inflammatory drugs are more specific in their effects on eicosanoid synthesis than are steroidal anti-inflammatory drugs.

Researchers have found that enkephalin receptors are upregulated in cocaine addicts when compared to non-users.It is likely that the action of cocaine

Second messengers

First messengers may bind to a membrane receptor that is an ion channel,which promotes a change in membrane polarity.

The enzyme that catalyzes the production of cAMP from ATP is phosphodiesterase.

In which situation would an injected drug be the most effective agonist for an endogenous chemical messenger?

Cyclic AMP activates allosteric proteins.

Which of the following are ways in which binding of a chemical messenger with a cell's receptor can bring about a cellular response?

Which of the following statements is TRUE?

Competition for receptors is strictly a pharmacological phenomenon,since naturally occurring chemical messengers do not compete with each other for the same receptor site.

Which of the following is known to be a second messenger?

The process whereby repeated exposure to a hormone can cause a decrease in the number of receptors for that hormone is called

Two cell types having the same type of receptor for a chemical messenger will always respond to that messenger in the same way.

Homeostasis: A Framework for Human Physiology

Chemical Composition of the Body and Its Relation to Physiology

Cellular Structure, Proteins, and Metabolic Pathways

Movement of Solutes and Water Across Cell Membranes

Neuronal Signaling and the Structure of the Nervous System

Sensory Physiology

Consciousness, the Brain, and Behavior

Muscle

Control Body Movement

The Endocrine System

Cardiovascular Physiology

Respiratory Physiology

The Kidneys and Regulation of Water and Inorganic Ions

The Digestion and Absorption of Food

Regulation of Organic Metabolism and Energy Balance

Reproduction

The Immune System

Filters