Question 1

Adenylate cyclase

Accepted Answer

A)  depends upon GTP for activation. 
B)  catalyzes the formation of cyclic AMP from AMP. 
C)  is stimulated in fat cells by the binding of insulin. 
D)  is a soluble protein found in almost all eukaryotic cells. 
E)  is feedback regulated by ATP. 
A)  depends upon GTP for activation. 
B)  catalyzes the formation of cyclic AMP from AMP. 
C)  is stimulated in fat cells by the binding of insulin. 
D)  is a soluble protein found in almost all eukaryotic cells. 
E)  is feedback regulated by ATP.

Question 2

Using the figure above, where does phospholipase C cleave?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Question 3

GTP is essential in the hormone mediated production of cAMP. Its role is to

Accepted Answer

A)  stimulate the activity of aspartate transcarbamoylase. 
B)  increase the cellular level of ATP by serving as a substrate in the synthesis of ATP. 
C)  bind to the G-protein forming a complex which is necessary for the activation of adenylate cyclase. 
D)  bind to EF-tu forming a complex necessary for the insertion of ATP into the A-site. 
A)  stimulate the activity of aspartate transcarbamoylase. 
B)  increase the cellular level of ATP by serving as a substrate in the synthesis of ATP. 
C)  bind to the G-protein forming a complex which is necessary for the activation of adenylate cyclase. 
D)  bind to EF-tu forming a complex necessary for the insertion of ATP into the A-site.

Question 4

Initial communication of environmental stimuli to the intracellular milieu via receptor-ligand binding is called

Accepted Answer

A)  extracellular signaling. 
B)  cellular response. 
C)  intracellular transmission. 
D)  contact inhibition. 
E)  exocytosis. 
A)  extracellular signaling. 
B)  cellular response. 
C)  intracellular transmission. 
D)  contact inhibition. 
E)  exocytosis.

Question 5

What is a function of the G-protein βγ dimer?

Accepted Answer

A)  As an anchor protein in the membrane 
B)  Exchange of GTP for GDP 
C)  Hydrolysis of GTP 
D)  Regulation of ion channel opening 
E)  Regulation of phosphodiesterase activity 
A)  As an anchor protein in the membrane 
B)  Exchange of GTP for GDP 
C)  Hydrolysis of GTP 
D)  Regulation of ion channel opening 
E)  Regulation of phosphodiesterase activity

Question 6

In the figure above which letter represents KD?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 7

What is the immediate trigger for the dissociation of the α and βγ subunits of the G-protein?

Accepted Answer

A)  Association with adenyl cyclase 
B)  Binding of GTP 
C)  Dissociation of GDP 
D)  Dissociation of hormone 
E)  Hydrolysis of GTP 
A)  Association with adenyl cyclase 
B)  Binding of GTP 
C)  Dissociation of GDP 
D)  Dissociation of hormone 
E)  Hydrolysis of GTP

Question 8

What is the most common event in the type of intracellular signal transduction that uses a second messenger?

Accepted Answer

A)  Acetylation 
B)  Carboxylation 
C)  Glucuronidation 
D)  Phosphorylation 
E)  Sulfation 
A)  Acetylation 
B)  Carboxylation 
C)  Glucuronidation 
D)  Phosphorylation 
E)  Sulfation

Question 9

What type of signaling involves molecules called "local mediators"?

Accepted Answer

A)  Autocrine 
B)  Endocrine 
C)  Juxtacrine 
D)  Paracrine 
E)  Synaptic 
A)  Autocrine 
B)  Endocrine 
C)  Juxtacrine 
D)  Paracrine 
E)  Synaptic

Question 10

Autocrine regulation refers to

Accepted Answer

A)  secretion of a chemical regulator which is transported to different tissues via the bloodstream where it acts to regulate cell metabolism. 
B)  synthesis and secretion of a hormone. 
C)  control of the cellular ATP levels by mitogenic agents. 
D)  synthesis and secretion of an autostimulatory growth regulating agent. 
E)  None of the above. 
A)  secretion of a chemical regulator which is transported to different tissues via the bloodstream where it acts to regulate cell metabolism. 
B)  synthesis and secretion of a hormone. 
C)  control of the cellular ATP levels by mitogenic agents. 
D)  synthesis and secretion of an autostimulatory growth regulating agent. 
E)  None of the above.

Question 11

What is the function of rapsyn?

Accepted Answer

A)  Antagonist for glutamate 
B)  Concentrate acetylcholine receptors in membrane 
C)  Degrade GABA 
D)  Inactivator of voltage-gated channels 
E)  Reuptake of serotonin 
A)  Antagonist for glutamate 
B)  Concentrate acetylcholine receptors in membrane 
C)  Degrade GABA 
D)  Inactivator of voltage-gated channels 
E)  Reuptake of serotonin

Question 12

Which phospholipase releases arachidonic acid from the membrane?

Accepted Answer

A)  A1 
B)  A2 
C)  B 
D)  C 
E)  D 
A)  A1 
B)  A2 
C)  B 
D)  C 
E)  D

Question 13

Why does endocrine signaling result in a long-term response?

Accepted Answer

A)  The hormone is bound covalently to the receptor 
B)  The hormone is metabolized slowly 
C)  The receptor has a high affinity for hormone 
D)  There is a high concentration of hormone in blood 
E)  There is a rapid rate of synthesis of hormone 
A)  The hormone is bound covalently to the receptor 
B)  The hormone is metabolized slowly 
C)  The receptor has a high affinity for hormone 
D)  There is a high concentration of hormone in blood 
E)  There is a rapid rate of synthesis of hormone

Question 14

Why does the rapid reduction in ligand concentration play a role in terminating cell response in synaptic signaling, and not in endocrine signaling?

Accepted Answer

A)  Antagonists are also present in the synapse 
B)  Hormones do not have degradative pathways 
C)  The receptors can be up-regulated in the synapse 
D)  The volume of the ligand environment is lower in the synapse 
E)  There is no regulation of hormone synthesis 
A)  Antagonists are also present in the synapse 
B)  Hormones do not have degradative pathways 
C)  The receptors can be up-regulated in the synapse 
D)  The volume of the ligand environment is lower in the synapse 
E)  There is no regulation of hormone synthesis

Question 15

What happens when tyrosines on receptor tyrosine kinases are autophosphorylated?

Accepted Answer

A)  Additional ligand is bound 
B)  The ligand is degraded 
C)  The receptor dissociates from the membrane 
D)  The receptors are dimerized 
E)  They are recognized by other proteins 
A)  Additional ligand is bound 
B)  The ligand is degraded 
C)  The receptor dissociates from the membrane 
D)  The receptors are dimerized 
E)  They are recognized by other proteins

Question 16

What type of regulation controls the activity of protein kinase A?

Accepted Answer

A)  Allosteric interaction 
B)  Compartmentation 
C)  Covalent modification 
D)  Induction 
E)  Protein-protein interaction 
A)  Allosteric interaction 
B)  Compartmentation 
C)  Covalent modification 
D)  Induction 
E)  Protein-protein interaction

Question 17

The participation of nitric oxide in signal transduction

Accepted Answer

A)  depends upon interaction with a heterotrimeric guanine nucleotide-binding protein. 
B)  is mediated by a receptor localized in the nucleus. 
C)  requires the oxidation of lysine by nitric oxide synthase. 
D)  results in the activation of guanylyl cyclase. 
A)  depends upon interaction with a heterotrimeric guanine nucleotide-binding protein. 
B)  is mediated by a receptor localized in the nucleus. 
C)  requires the oxidation of lysine by nitric oxide synthase. 
D)  results in the activation of guanylyl cyclase.

Question 18

What is the major signaling molecule that binds to soluble guanylate cyclase?

Accepted Answer

A)  cAMP 
B)  Epinephrine 
C)  Glucagon 
D)  Insulin 
E)  NO 
A)  cAMP 
B)  Epinephrine 
C)  Glucagon 
D)  Insulin 
E)  NO

Question 19

The amount of phospahtidylinositol-4,5-bisphosphate in the membrane is too small to fill the need for prolonged signaling. What is an alternative source of diacylglycerol?

Accepted Answer

A)  Acetyl CoA 
B)  Cardiolipin 
C)  Intracellular IP2 
D)  Phosphatidyl choline and ethanolamine 
E)  Triacylglycerols 
A)  Acetyl CoA 
B)  Cardiolipin 
C)  Intracellular IP2 
D)  Phosphatidyl choline and ethanolamine 
E)  Triacylglycerols

Question 20

A gain of function mutation to a gene encoding a protein in a signal transduction pathway

Accepted Answer

A)  cannot involve the genes encoding heterotrimeric guanine nucleotide-binding proteins. 
B)  causes constitutive activation of signal transduction. 
C)  is characterized by a measurable increase in the circulating concentration of the specific hormone agonist. 
D)  is invariably germ?line in origin. 
A)  cannot involve the genes encoding heterotrimeric guanine nucleotide-binding proteins. 
B)  causes constitutive activation of signal transduction. 
C)  is characterized by a measurable increase in the circulating concentration of the specific hormone agonist. 
D)  is invariably germ?line in origin.

Exam 13: Fundamentals of Signal Transduction

Adenylate cyclase

Using the figure above, where does phospholipase C cleave?

GTP is essential in the hormone mediated production of cAMP. Its role is to

Initial communication of environmental stimuli to the intracellular milieu via receptor-ligand binding is called

What is a function of the G-protein βγ dimer?

In the figure above which letter represents KD?

What is the immediate trigger for the dissociation of the α and βγ subunits of the G-protein?

What is the most common event in the type of intracellular signal transduction that uses a second messenger?

What type of signaling involves molecules called "local mediators"?

Autocrine regulation refers to

What is the function of rapsyn?

Which phospholipase releases arachidonic acid from the membrane?

Why does endocrine signaling result in a long-term response?

Why does the rapid reduction in ligand concentration play a role in terminating cell response in synaptic signaling, and not in endocrine signaling?

What happens when tyrosines on receptor tyrosine kinases are autophosphorylated?

What type of regulation controls the activity of protein kinase A?

The participation of nitric oxide in signal transduction

What is the major signaling molecule that binds to soluble guanylate cyclase?

The amount of phospahtidylinositol-4,5-bisphosphate in the membrane is too small to fill the need for prolonged signaling. What is an alternative source of diacylglycerol?

A gain of function mutation to a gene encoding a protein in a signal transduction pathway

Eukaryotic Cell Structure

DNA and RNA: Composition and Structure

Protein I: Composition and Structure

DNA Replication, Recombination, and Repair

RNA: Transcription and Rna Processing

Protein Synthesis: Translation and Posttranslational Modifications

Recombinant Dna and Biotechnology

Regulation of Gene Expression

Protein II: Structure-Function Relationships in Protein Families

Enzymes: Classification, Kinetics, and Control

The Cytochromes P450 and Nitric Oxide Synthases

Biological Membranes: Structure and Membrane Transport

Bioenergetics and Oxidative Metabolism

Carbohydrate Metabolism I: Major Metabolic Pathways and Their Control

Carbohydrate Metabolism II: Special Pathways and Glycoconjugates

Lipid Metabolism I: Synthesis, Storage, and Utilization of Fatty Acids and Triacylglycerols

Lipid Metabolism II: Pathways of Metabolism of Special Lipids

Amino Acid Metabolism

Purine and Pyrimidine Nucleotide Metabolism

Metabolic Interrelationships

Biochemistry of Hormones

Molecular Cell Biology

Cell Cycle, Programmed Cell Death, and Cancer

Digestion and Absorption of Basic Nutritional Constituents

Digestion and Absorption of Basic Nutritional Constituents

Principles of Nutrition I and II

Filters

In the figure above which letter represents K_D?