Question 1

Protein kinase C is allosterically regulated by which second messengers?

Accepted Answer

A)  inositol triphosphate (IP3) 
B)  diacylglycerol (DAG) 
C)  calcium (Ca2+) 
D)  both diacylglycerol (DAG) and calcium (Ca2+) 
E)  both inositol triphosphate (IP3) and diacylglycerol (DAG) 
A)  inositol triphosphate (IP3) 
B)  diacylglycerol (DAG) 
C)  calcium (Ca2+) 
D)  both diacylglycerol (DAG) and calcium (Ca2+) 
E)  both inositol triphosphate (IP3) and diacylglycerol (DAG)

Question 2

Which signaling mechanism is used most predominantly in plants?

Accepted Answer

A)  cyclic-nucleotide dependent protein kinases 
B)  DNA-binding nuclear steroid receptors 
C)  G protein-coupled receptors 
D)  protein serine/threonine kinases 
E)  protein tyrosine kinases 
A)  cyclic-nucleotide dependent protein kinases 
B)  DNA-binding nuclear steroid receptors 
C)  G protein-coupled receptors 
D)  protein serine/threonine kinases 
E)  protein tyrosine kinases

Question 3

Describe the role of G proteins in olfactory sensory transduction

Accepted Answer

G proteins play a crucial role in olfact

Question 4

Cholera toxin leads to the activation of the $\alpha$subunit of G-proteins through what kind of covalent modification?

Accepted Answer

A)  phosphorylation 
B)  adenylylation 
C)  acetylation 
D)  palmitoylation 
E)  ADP-ribosylation 
A)  phosphorylation 
B)  adenylylation 
C)  acetylation 
D)  palmitoylation 
E)  ADP-ribosylation

Question 5

How does the insulin receptor differ from the erythropoietin receptor?

Accepted Answer

A)  Upon binding its signal molecule, the insulin receptor has two-fold symmetry, while the erythropoietin receptor does not. 
B)  Both the insulin and erythropoietin receptors trigger MAPK cascades. 
C)  The insulin receptor contains a tyrosine kinase, while the erythropoetin receptor does not. 
D)  The insulin receptor is phosphorylated in response to signal molecule binding, while the erythropoietin receptor does not. 
A)  Upon binding its signal molecule, the insulin receptor has two-fold symmetry, while the erythropoietin receptor does not. 
B)  Both the insulin and erythropoietin receptors trigger MAPK cascades. 
C)  The insulin receptor contains a tyrosine kinase, while the erythropoetin receptor does not. 
D)  The insulin receptor is phosphorylated in response to signal molecule binding, while the erythropoietin receptor does not.

Question 6

Calmodulin is a(n):

Accepted Answer

A)  allosteric activator of calcium-dependent enzymes. 
B)  allosteric inhibitor of calcium-dependent enzymes. 
C)  calcium-dependent enzyme. 
D)  cell surface calcium receptor. 
E)  regulatory subunit of calcium-dependent enzymes. 
A)  allosteric activator of calcium-dependent enzymes. 
B)  allosteric inhibitor of calcium-dependent enzymes. 
C)  calcium-dependent enzyme. 
D)  cell surface calcium receptor. 
E)  regulatory subunit of calcium-dependent enzymes.

Question 7

What is a Scatchard plot, and how can it be used to determine the number of receptor molecules on a cell and their affinity for a ligand?

Accepted Answer

A Scatchard plot is a graphical represen

Question 8

Explain the importance of membrane rafts in cell signaling pathways.

Accepted Answer

Membrane rafts are specialized microdoma

Question 9

Which factor is NOT a feature of signal transduction?

Accepted Answer

A)  integration of multiple pathways toward the same downstream response 
B)  signal amplification 
C)  covalent binding between the ligand and the receptor 
D)  desensitization or adaptation of the receptor 
E)  variable affinity for different signaling components 
A)  integration of multiple pathways toward the same downstream response 
B)  signal amplification 
C)  covalent binding between the ligand and the receptor 
D)  desensitization or adaptation of the receptor 
E)  variable affinity for different signaling components

Question 10

In the plant signaling pathways employing receptor-like kinases (RLKs), what does NOT occur?

Accepted Answer

A)  activation of a MAPK cascade 
B)  autophosphorylation of receptor 
C)  dimerization of receptor 
D)  ligand binding to receptor 
E)  phosphorylation of key proteins on Tyr residues 
A)  activation of a MAPK cascade 
B)  autophosphorylation of receptor 
C)  dimerization of receptor 
D)  ligand binding to receptor 
E)  phosphorylation of key proteins on Tyr residues

Question 11

Which protein is phosphorylated in response to an insulin/insulin receptor interaction?

Accepted Answer

A)  IRS-1 
B)  phosphatidyl inositol-4,5-bisphosphate 
C)  GDP 
D)  both IRS-1 and phosphatidyl inositol-4,5-bisphosphate 
E)  both phosphatidyl inositol-4,5-bisphosphate and GDP 
A)  IRS-1 
B)  phosphatidyl inositol-4,5-bisphosphate 
C)  GDP 
D)  both IRS-1 and phosphatidyl inositol-4,5-bisphosphate 
E)  both phosphatidyl inositol-4,5-bisphosphate and GDP

Question 12

Phosphorylation of a threonine in the T-loop of cyclin-dependent kinases (CDK) causes what event to occur?

Accepted Answer

A)  The T loop is rearranged so that cyclin can bind. 
B)  ADP is forced to dissociate from CDK. 
C)  The CDK is inactivated. 
D)  Multiple arginine residues form ionic interactions with the threonine. 
A)  The T loop is rearranged so that cyclin can bind. 
B)  ADP is forced to dissociate from CDK. 
C)  The CDK is inactivated. 
D)  Multiple arginine residues form ionic interactions with the threonine.

Question 13

In kidneys, what is the response when the atrial natriuretic factor (ANF) binds to its receptor?

Accepted Answer

A)  increased cAMP concentration in the cytosol 
B)  activation of protein kinase G (PKG) 
C)  stimulation of water and sodium excretion 
D)  both increased cAMP concentration in the cytosol and stimulation of water and sodium excretion 
E)  both increased cAMP concentration in the cytosol and activation of protein kinase G (PKG) 
A)  increased cAMP concentration in the cytosol 
B)  activation of protein kinase G (PKG) 
C)  stimulation of water and sodium excretion 
D)  both increased cAMP concentration in the cytosol and stimulation of water and sodium excretion 
E)  both increased cAMP concentration in the cytosol and activation of protein kinase G (PKG)

Question 14

Protein kinase A (PKA) is:

Accepted Answer

A)  activated by covalent binding of cyclic AMP. 
B)  affected by cyclic AMP only under unusual circumstances. 
C)  allosterically activated by cyclic AMP. 
D)  competitively inhibited by cyclic AMP. 
E)  noncompetitively inhibited by cyclic AMP. 
A)  activated by covalent binding of cyclic AMP. 
B)  affected by cyclic AMP only under unusual circumstances. 
C)  allosterically activated by cyclic AMP. 
D)  competitively inhibited by cyclic AMP. 
E)  noncompetitively inhibited by cyclic AMP.

Question 15

Explain how an increase in cytosolic Ca2+ concentration from 10-8 M to 10-6 M activates a Ca2+ and calmodulin-dependent enzyme.

Accepted Answer

An increase in cytosolic Ca2+ concentrat

Question 16

Which statement concerning cyclin-dependent protein kinases is NOT correct?

Accepted Answer

A)  Each type of cell contains one specific form (isozyme). 
B)  Their activity fluctuates during the cell cycle. 
C)  Their activity is regulated by changes in gene expression, protein phosphorylation, and proteolysis. 
D)  Their activity is regulated by cyclins. 
E)  They can alter the activity of proteins involved in the progression of cells through the cell cycle. 
A)  Each type of cell contains one specific form (isozyme). 
B)  Their activity fluctuates during the cell cycle. 
C)  Their activity is regulated by changes in gene expression, protein phosphorylation, and proteolysis. 
D)  Their activity is regulated by cyclins. 
E)  They can alter the activity of proteins involved in the progression of cells through the cell cycle.

Question 17

_____ do(es) NOT bind to heterotrimeric G proteins.

Accepted Answer

A)  GTP-GDP exchange factors (GEFs) 
B)  GTPase activating proteins (GAPs) 
C)  GPCRs 
D)  cGMP 
E)  GDP 
A)  GTP-GDP exchange factors (GEFs) 
B)  GTPase activating proteins (GAPs) 
C)  GPCRs 
D)  cGMP 
E)  GDP

Question 18

The following sequences are all phosphorylated by the insulin receptor tyrosine kinase.

Accepted Answer

The insulin receptor is a tyrosine kinas

Question 19

Hormone-activated phospholipase C can convert phosphatidylinositol 4,5-bisphosphate to:

Accepted Answer

A)  diacylglycerol + inositol triphosphate. 
B)  diacylglycerol + inositol+ phosphate. 
C)  glycerol + inositol + phosphate. 
D)  glycerol + phosphoserine. 
E)  phosphatidyl glycerol + inositol + phosphate. 
A)  diacylglycerol + inositol triphosphate. 
B)  diacylglycerol + inositol+ phosphate. 
C)  glycerol + inositol + phosphate. 
D)  glycerol + phosphoserine. 
E)  phosphatidyl glycerol + inositol + phosphate.

Question 20

What is meant by the two-component system of bacterial cell signaling?

Accepted Answer

The two-component system is a simple and

Exam 12: Biosignaling

Protein kinase C is allosterically regulated by which second messengers?

Which signaling mechanism is used most predominantly in plants?

Describe the role of G proteins in olfactory sensory transduction

Cholera toxin leads to the activation of the α\alphaα subunit of G-proteins through what kind of covalent modification?

How does the insulin receptor differ from the erythropoietin receptor?

Calmodulin is a(n):

What is a Scatchard plot, and how can it be used to determine the number of receptor molecules on a cell and their affinity for a ligand?

Explain the importance of membrane rafts in cell signaling pathways.

Which factor is NOT a feature of signal transduction?

In the plant signaling pathways employing receptor-like kinases (RLKs), what does NOT occur?

Which protein is phosphorylated in response to an insulin/insulin receptor interaction?

Phosphorylation of a threonine in the T-loop of cyclin-dependent kinases (CDK) causes what event to occur?

In kidneys, what is the response when the atrial natriuretic factor (ANF) binds to its receptor?

Protein kinase A (PKA) is:

Explain how an increase in cytosolic Ca2+ concentration from 10-8 M to 10-6 M activates a Ca2+ and calmodulin-dependent enzyme.

Which statement concerning cyclin-dependent protein kinases is NOT correct?

_____ do(es) NOT bind to heterotrimeric G proteins.

The following sequences are all phosphorylated by the insulin receptor tyrosine kinase.

Hormone-activated phospholipase C can convert phosphatidylinositol 4,5-bisphosphate to:

What is meant by the two-component system of bacterial cell signaling?

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

Cholera toxin leads to the activation of the $\alpha$ subunit of G-proteins through what kind of covalent modification?

Explain how an increase in cytosolic Ca²⁺ concentration from 10^-⁸ M to 10^-⁶ M activates a Ca²⁺and calmodulin-dependent enzyme.