Question 1

What are ligands that bind receptor but produce no subsequent second messenger called?

Accepted Answer

A)  Antagonist 
B)  Competitor 
C)  Disrupter 
D)  Inhibitor 
E)  Negator 
A)  Antagonist 
B)  Competitor 
C)  Disrupter 
D)  Inhibitor 
E)  Negator A

Question 2

What is the major type of cell that responds to cytokines?

Accepted Answer

A)  Blood-forming 
B)  Fibroblasts 
C)  Hepatic 
D)  Peripheral nervous system 
E)  Smooth muscle 
A)  Blood-forming 
B)  Fibroblasts 
C)  Hepatic 
D)  Peripheral nervous system 
E)  Smooth muscle A

Question 3

What is the most common mechanism for deactivation of the hormone receptor in G-protein-associated signaling?

Accepted Answer

A)  Degradation of hormone 
B)  Degradation of receptor 
C)  GTP hydrolysis 
D)  Phosphorylation of receptor 
E)  Receptor internalization 
A)  Degradation of hormone 
B)  Degradation of receptor 
C)  GTP hydrolysis 
D)  Phosphorylation of receptor 
E)  Receptor internalization D

Question 4

What type of signaling are steroids and polypeptides involved in?

Accepted Answer

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

Question 5

How many kinase steps are there from activation of the Ras protein to, and including, phosphorylation of the final target protein?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 6

Which neurotransmitter is inactivated by an ectoenzyme?

Accepted Answer

A)  Acetylcholine 
B)  GABA 
C)  Glutamate 
D)  Glycine 
E)  Serotonin 
A)  Acetylcholine 
B)  GABA 
C)  Glutamate 
D)  Glycine 
E)  Serotonin

Question 7

Which enzyme does sildenfil citrate (Viagra) inhibit?

Accepted Answer

A)  Adenylcyclase 
B)  Guanyl cyclase 
C)  Nitric oxide synthase 
D)  Phosphodiesterase 5 
E)  Protein kinase G 
A)  Adenylcyclase 
B)  Guanyl cyclase 
C)  Nitric oxide synthase 
D)  Phosphodiesterase 5 
E)  Protein kinase G

Question 8

Signal transduction through the insulin receptor is regulated by autophosphorylation of ______________ residues.

Accepted Answer

A)  aspartate 
B)  histidine 
C)  serine 
D)  threonine 
E)  tyrosine 
A)  aspartate 
B)  histidine 
C)  serine 
D)  threonine 
E)  tyrosine

Question 9

Which of the following neurotransmitters would promote chloride entry into the post-synaptic terminal?

Accepted Answer

A)  Acetylcholine 
B)  ATP 
C)  GABA 
D)  Glutamate 
E)  Serotonin 
A)  Acetylcholine 
B)  ATP 
C)  GABA 
D)  Glutamate 
E)  Serotonin

Question 10

During signal transduction, fluctuations in the concentration of cytosolic calcium are controlled by

Accepted Answer

A)  calmodulin and phospholipase C. 
B)  gated Ca2+ channels and Ca2+-ATPase. 
C)  parathyroid hormone and calcitonin. 
D)  protein kinase and phosphoprotein phosphatase. 
A)  calmodulin and phospholipase C. 
B)  gated Ca2+ channels and Ca2+-ATPase. 
C)  parathyroid hormone and calcitonin. 
D)  protein kinase and phosphoprotein phosphatase.

Question 11

What molecule is the most common ligand for "gating" calcium channels?

Accepted Answer

A)  ATP 
B)  cAMP 
C)  cGMP 
D)  Diacylglycerol 
E)  IP3 
A)  ATP 
B)  cAMP 
C)  cGMP 
D)  Diacylglycerol 
E)  IP3

Question 12

Diacylglycerol is a(n)____________ that promotes _____________.

Accepted Answer

A)  insulin agonist; tyrosine phosphorylation 
B)  phosphodiesterase inhibitor; cAMP accumulation 
C)  second messenger; protein kinase C activation 
D)  steroid-like hormone; protein dimerization 
A)  insulin agonist; tyrosine phosphorylation 
B)  phosphodiesterase inhibitor; cAMP accumulation 
C)  second messenger; protein kinase C activation 
D)  steroid-like hormone; protein dimerization

Question 13

Inositol 1,4,5-trisphosphate

Accepted Answer

A)  binds to a specific site on protein kinase A. 
B)  binds to a specific site on phosphoprotein phosphatase. 
C)  is formed by three phosphorylations of inositol in the presence of ATP. 
D)  regulates a Ca2+ channel in the endoplasmic reticulum. 
A)  binds to a specific site on protein kinase A. 
B)  binds to a specific site on phosphoprotein phosphatase. 
C)  is formed by three phosphorylations of inositol in the presence of ATP. 
D)  regulates a Ca2+ channel in the endoplasmic reticulum.

Question 14

What happens when SMADs dimerize?

Accepted Answer

A)  A protein kinase activity is revealed and SMAD autophosphorylates 
B)  Nuclear location sequences are exposed 
C)  SH3 domains bind 
D)  The βγ subunits dissociate from the α subunit 
E)  The folding of SMAD becomes more compact 
A)  A protein kinase activity is revealed and SMAD autophosphorylates 
B)  Nuclear location sequences are exposed 
C)  SH3 domains bind 
D)  The βγ subunits dissociate from the α subunit 
E)  The folding of SMAD becomes more compact

Question 15

What is the term used to indicate the mechanism of protein kinase cascades?

Accepted Answer

A)  Addition 
B)  Amplification 
C)  Increase 
D)  Logarithmic 
E)  Multiplication 
A)  Addition 
B)  Amplification 
C)  Increase 
D)  Logarithmic 
E)  Multiplication

Question 16

In skeletal muscle cells _______________ is responsible for the flux of Ca2+ from the cytosol to the lumen of the sarcoplasmic reticulum.

Accepted Answer

A)  calmodulin-dependent protein kinase 
B)  Ca2+ - ATPase 
C)  nitric oxide synthase 
D)  phospholipase C-beta 
E)  protein kinase C 
A)  calmodulin-dependent protein kinase 
B)  Ca2+ - ATPase 
C)  nitric oxide synthase 
D)  phospholipase C-beta 
E)  protein kinase C

Question 17

Why is the hydrolysis of GTP by a G-protein essentially irreversible?

Accepted Answer

A)  GDP immediately hydrolyzes to GMP and Pi 
B)  GDP is metabolized to cGMP 
C)  GDP remains bound after Pi is liberated 
D)  GTP cannot be synthesized from GDP 
E)  The Km for Pi is too low 
A)  GDP immediately hydrolyzes to GMP and Pi 
B)  GDP is metabolized to cGMP 
C)  GDP remains bound after Pi is liberated 
D)  GTP cannot be synthesized from GDP 
E)  The Km for Pi is too low

Question 18

Formation of a GDP-gamma alpha subunit complex (gamma alpha GDP)

Accepted Answer

A)  follows phosphorylation of the gamma subunit. 
B)  increases association with target proteins. 
C)  is stimulated by hydrolysis-resistant analogs of GTP. 
D)  precedes assembly of the gamma heterotrimer. 
E)  requires hydrolysis of ATP. 
A)  follows phosphorylation of the gamma subunit. 
B)  increases association with target proteins. 
C)  is stimulated by hydrolysis-resistant analogs of GTP. 
D)  precedes assembly of the gamma heterotrimer. 
E)  requires hydrolysis of ATP.

Question 19

Adenylyl cyclase

Accepted Answer

A)  catalyzes the ADP ribosylation of proteins. 
B)  catalyzes the dephosphorylation of phospho?Ser residues on enzymes. 
C)  catalyzes the hydrolysis of ATP to ADP and Pi. 
D)  diffuses to the nucleus to function as a transcription factor. 
E)  is regulated by protein-protein interactions. 
A)  catalyzes the ADP ribosylation of proteins. 
B)  catalyzes the dephosphorylation of phospho?Ser residues on enzymes. 
C)  catalyzes the hydrolysis of ATP to ADP and Pi. 
D)  diffuses to the nucleus to function as a transcription factor. 
E)  is regulated by protein-protein interactions.

Question 20

What is required for STAT (signal transducers and activators of transcription) to respond to a cytokine signal?

Accepted Answer

A)  Binding of cytokine to intracellular receptor 
B)  Dissociation of the receptor subunits 
C)  Dissociation of the STAT subunits 
D)  Formation of cAMP 
E)  Phosphorylation of the cytokine receptor 
A)  Binding of cytokine to intracellular receptor 
B)  Dissociation of the receptor subunits 
C)  Dissociation of the STAT subunits 
D)  Formation of cAMP 
E)  Phosphorylation of the cytokine receptor

Exam 13: Fundamentals of Signal Transduction

What are ligands that bind receptor but produce no subsequent second messenger called?

What is the major type of cell that responds to cytokines?

What is the most common mechanism for deactivation of the hormone receptor in G-protein-associated signaling?

What type of signaling are steroids and polypeptides involved in?

How many kinase steps are there from activation of the Ras protein to, and including, phosphorylation of the final target protein?

Which neurotransmitter is inactivated by an ectoenzyme?

Which enzyme does sildenfil citrate (Viagra) inhibit?

Signal transduction through the insulin receptor is regulated by autophosphorylation of ______________ residues.

Which of the following neurotransmitters would promote chloride entry into the post-synaptic terminal?

During signal transduction, fluctuations in the concentration of cytosolic calcium are controlled by

What molecule is the most common ligand for "gating" calcium channels?

Diacylglycerol is a(n)____________ that promotes _____________.

Inositol 1,4,5-trisphosphate

What happens when SMADs dimerize?

What is the term used to indicate the mechanism of protein kinase cascades?

In skeletal muscle cells _______________ is responsible for the flux of Ca2+ from the cytosol to the lumen of the sarcoplasmic reticulum.

Why is the hydrolysis of GTP by a G-protein essentially irreversible?

Formation of a GDP-gamma alpha subunit complex (gamma alpha GDP)

Adenylyl cyclase

What is required for STAT (signal transducers and activators of transcription) to respond to a cytokine signal?

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

Diacylglycerol is a(n) that promotes _.

In skeletal muscle cells _______________ is responsible for the flux of Ca²⁺ from the cytosol to the lumen of the sarcoplasmic reticulum.