Question 1

Which heterotrimeric G proteins couple receptors to adenylyl cyclase via the activation of GTP-bound G $\alpha$  subunits?

Accepted Answer

A) Gs family 
B) Gq family 
C) Gi family 
D) G12/13 family 
E) Gr family 
A) Gs family 
B) Gq family 
C) Gi family 
D) G12/13 family 
E) Gr family A

Question 2

What gene in C.elegans was found to play a critical role in apoptosis?

Accepted Answer

A) CED-3 
B) DEG-3 
C) NSO-1 
D) Eco R1 
E) CEL-3 
A) CED-3 
B) DEG-3 
C) NSO-1 
D) Eco R1 
E) CEL-3 A

Question 3

What is the function of carbon number 1 on the inositol ring of phosphatidylinositol?

Accepted Answer

A) It binds to steroid receptors. 
B) It joins inositol to diacylglycerol. 
C) It joins a phosphate group to diacyglycerol. 
D) It joins glucose to diacylglycerol. 
E) It joins two diacyglycerol molecules together. 
A) It binds to steroid receptors. 
B) It joins inositol to diacylglycerol. 
C) It joins a phosphate group to diacyglycerol. 
D) It joins glucose to diacylglycerol. 
E) It joins two diacyglycerol molecules together. B

Question 4

What stimulus triggered by the binding of acetylcholine then activates nitric oxide synthase?

Accepted Answer

A) a rise in cytoplasmic Ca2+ concentration 
B) a drop in cytoplasmic Ca2+ concentration 
C) an action potential 
D) cellular hyperpolarization 
E) release of cGMP 
A) a rise in cytoplasmic Ca2+ concentration 
B) a drop in cytoplasmic Ca2+ concentration 
C) an action potential 
D) cellular hyperpolarization 
E) release of cGMP

Question 5

In what form do animal cells store glucose?

Accepted Answer

A) glucogen 
B) glycogen 
C) agarose 
D) amylose 
E) amylopectin 
A) glucogen 
B) glycogen 
C) agarose 
D) amylose 
E) amylopectin

Question 6

Which of the following are not natural ligands that bind to G-protein coupled receptors?

Accepted Answer

A) hormones 
B) neurotransmitters 
C) chemoattractants 
D) opium derivatives 
E) steroid hormones 
A) hormones 
B) neurotransmitters 
C) chemoattractants 
D) opium derivatives 
E) steroid hormones

Question 7

Which heterotrimeric G proteins are less well characterized than the other G protein families and have had their inappropriate activation associated with excessive cell proliferation and malignant transformations?

Accepted Answer

A) Gs family 
B) Gq family 
C) Gi family 
D) G12/13 family 
E) Gr family 
A) Gs family 
B) Gq family 
C) Gi family 
D) G12/13 family 
E) Gr family

Question 8

Accessory proteins that maintain monomeric G proteins in an inactive state by inhibiting GDP-GTP exchange are called:

Accepted Answer

A) GAPs 
B) GEFs 
C) GDIs 
D) RASps 
E) MAPs 
A) GAPs 
B) GEFs 
C) GDIs 
D) RASps 
E) MAPs

Question 9

The effect of inositol triphosphate is usually transient because __________.

Accepted Answer

A) it is so stable 
B) it is rapidly inactivated enzymatically 
C) it is slowly activated enzymatically 
D) it is so big 
E) it is so small 
A) it is so stable 
B) it is rapidly inactivated enzymatically 
C) it is slowly activated enzymatically 
D) it is so big 
E) it is so small

Question 10

Once the kinase domain of receptor protein-tyrosine kinase has been activated,what does the activated receptor protein-tyrosine kinase do?

Accepted Answer

A) The receptor subunits denature. 
B) Each receptor subunit phosphorylates its partner on tyrosine residues found in regions adjacent to the kinase domain. 
C) Each receptor subunit phosphorylates itself on tyrosine residues found in regions adjacent to the kinase domain. 
D) The receptor subunits dephosphorylate each other. 
E) The receptor subunits refold into a more effective conformation. 
A) The receptor subunits denature. 
B) Each receptor subunit phosphorylates its partner on tyrosine residues found in regions adjacent to the kinase domain. 
C) Each receptor subunit phosphorylates itself on tyrosine residues found in regions adjacent to the kinase domain. 
D) The receptor subunits dephosphorylate each other. 
E) The receptor subunits refold into a more effective conformation.

Question 11

How is caspase-activated DNase (CAD)activated?

Accepted Answer

A) A caspase cleaves CAD,activating it. 
B) A caspase cleaves an activator of CAD,turning it on and causing it to activate CAD. 
C) A caspase cleaves a CAD inhibitor,relieving the CAD of inhibition. 
D) A caspase binds to CAD allosterically,activating it. 
E) None of these are correct. 
A) A caspase cleaves CAD,activating it. 
B) A caspase cleaves an activator of CAD,turning it on and causing it to activate CAD. 
C) A caspase cleaves a CAD inhibitor,relieving the CAD of inhibition. 
D) A caspase binds to CAD allosterically,activating it. 
E) None of these are correct.

Question 12

Which hormone is secreted by $\alpha$-cells in the pancreas in response to low blood glucose levels?

Accepted Answer

A) insulin 
B) glycogen 
C) glucagon 
D) epinephrine 
E) somatostatin 
A) insulin 
B) glycogen 
C) glucagon 
D) epinephrine 
E) somatostatin

Question 13

What is the largest protein superfamily encoded by animal genomes?

Accepted Answer

A) G-protein coupled receptors 
B) RTKs 
C) steroid receptors 
D) tubulin superfamily 
E) ligand-gated channels 
A) G-protein coupled receptors 
B) RTKs 
C) steroid receptors 
D) tubulin superfamily 
E) ligand-gated channels

Question 14

How is signaling by an activated G $\alpha$  subunit terminated?

Accepted Answer

A) The bound GTP is hydrolyzed to GMP. 
B) The bound GDP is hydrolyzed to GTP. 
C) The bound GTP is hydrolyzed to GDP. 
D) The bound GDP is phosphorylated to GTP. 
E) The G $\alpha$ subunit releases GDP and binds GTP. 
A) The bound GTP is hydrolyzed to GMP. 
B) The bound GDP is hydrolyzed to GTP. 
C) The bound GTP is hydrolyzed to GDP. 
D) The bound GDP is phosphorylated to GTP. 
E) The G $\alpha$ subunit releases GDP and binds GTP.

Question 15

Why did the smooth muscle in cultured strips of aorta not respond to acetylcholine by relaxing,while the smooth muscle of aortic rings did?

Accepted Answer

A) Smooth muscle cells in aortic strips are physically incapable of relaxing under any circumstances. 
B) Acetylcholine in the strips could not penetrate to the muscle cells while in the rings it could. 
C) Smooth muscle cells in aortic rings express acetylcholine receptors,while those in strips do not. 
D) The delicate endothelial layer in aortal strips had been rubbed away during dissection,while in aortal rings it remained intact. 
E) The endothelial layer in aortal strips was abnormally thickened,while in aortal rings it was not. 
A) Smooth muscle cells in aortic strips are physically incapable of relaxing under any circumstances. 
B) Acetylcholine in the strips could not penetrate to the muscle cells while in the rings it could. 
C) Smooth muscle cells in aortic rings express acetylcholine receptors,while those in strips do not. 
D) The delicate endothelial layer in aortal strips had been rubbed away during dissection,while in aortal rings it remained intact. 
E) The endothelial layer in aortal strips was abnormally thickened,while in aortal rings it was not.

Question 16

What is the name of a calcium-binding protein that acts in conjunction with calcium to bring about the responses associated with cytoplasmic rises in calcium ion concentration?

Accepted Answer

A) calpectin 
B) calmodulin 
C) calcariain 
D) callistin 
E) modulocalcin 
A) calpectin 
B) calmodulin 
C) calcariain 
D) callistin 
E) modulocalcin

Question 17

Once activated,what does caspase-9 itself activate?

Accepted Answer

A) phospholipase C 
B) protein kinase A 
C) other initiator caspases 
D) downstream executioner caspases 
E) downstream caspase-8 
A) phospholipase C 
B) protein kinase A 
C) other initiator caspases 
D) downstream executioner caspases 
E) downstream caspase-8

Question 18

Why does rhodopsin have an unusually stable structure for a GPCR?

Accepted Answer

A) Its ligand is permanently bound to the protein. 
B) A retinal group is permanently bound to the protein. 
C) The protein molecule can only exist in a single conformation in the absence of a stimulus. 
D) The protein molecule can only exist in a single conformation in the dark. 
E) All of these are correct. 
A) Its ligand is permanently bound to the protein. 
B) A retinal group is permanently bound to the protein. 
C) The protein molecule can only exist in a single conformation in the absence of a stimulus. 
D) The protein molecule can only exist in a single conformation in the dark. 
E) All of these are correct.

Question 19

How do cells in the body of a multicellular organism usually communicate with each other?

Accepted Answer

A) intracellular messenger molecules 
B) direct connection by cells through long projections 
C) extracellular messenger molecules 
D) electrical signals between cells 
E) ion transport between cells 
A) intracellular messenger molecules 
B) direct connection by cells through long projections 
C) extracellular messenger molecules 
D) electrical signals between cells 
E) ion transport between cells

Question 20

Specificity in MAP kinase pathways is sometimes achieved by spatial localization of the pathway's component proteins.Spatial localization of these components is done by structural (i.e.,nonenzymatic)proteins called _____________.

Accepted Answer

A) sequestration proteins 
B) partitioning proteins 
C) scaffolding proteins 
D) framework proteins 
E) spatial organization proteins 
A) sequestration proteins 
B) partitioning proteins 
C) scaffolding proteins 
D) framework proteins 
E) spatial organization proteins

Which heterotrimeric G proteins couple receptors to adenylyl cyclase via the activation of GTP-bound G _$\alpha$ subunits?

What gene in C.elegans was found to play a critical role in apoptosis?

What is the function of carbon number 1 on the inositol ring of phosphatidylinositol?

What stimulus triggered by the binding of acetylcholine then activates nitric oxide synthase?

In what form do animal cells store glucose?

Which of the following are not natural ligands that bind to G-protein coupled receptors?

Which heterotrimeric G proteins are less well characterized than the other G protein families and have had their inappropriate activation associated with excessive cell proliferation and malignant transformations?

Accessory proteins that maintain monomeric G proteins in an inactive state by inhibiting GDP-GTP exchange are called:

The effect of inositol triphosphate is usually transient because __________.

Once the kinase domain of receptor protein-tyrosine kinase has been activated,what does the activated receptor protein-tyrosine kinase do?

How is caspase-activated DNase (CAD)activated?

Which hormone is secreted by $\alpha$ -cells in the pancreas in response to low blood glucose levels?

What is the largest protein superfamily encoded by animal genomes?

How is signaling by an activated G _$\alpha$ subunit terminated?

Why did the smooth muscle in cultured strips of aorta not respond to acetylcholine by relaxing,while the smooth muscle of aortic rings did?

What is the name of a calcium-binding protein that acts in conjunction with calcium to bring about the responses associated with cytoplasmic rises in calcium ion concentration?

Once activated,what does caspase-9 itself activate?

Why does rhodopsin have an unusually stable structure for a GPCR?

How do cells in the body of a multicellular organism usually communicate with each other?

Specificity in MAP kinase pathways is sometimes achieved by spatial localization of the pathway's component proteins.Spatial localization of these components is done by structural (i.e.,nonenzymatic)proteins called _____________.

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics,enzymes and Metabolism

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

Exam 15: Cell Signaling and Signal Transduction: Communication Between Cells

Which heterotrimeric G proteins couple receptors to adenylyl cyclase via the activation of GTP-bound G α\alphaα subunits?

What gene in C.elegans was found to play a critical role in apoptosis?

What is the function of carbon number 1 on the inositol ring of phosphatidylinositol?

What stimulus triggered by the binding of acetylcholine then activates nitric oxide synthase?

In what form do animal cells store glucose?

Which of the following are not natural ligands that bind to G-protein coupled receptors?

Which heterotrimeric G proteins are less well characterized than the other G protein families and have had their inappropriate activation associated with excessive cell proliferation and malignant transformations?

Accessory proteins that maintain monomeric G proteins in an inactive state by inhibiting GDP-GTP exchange are called:

The effect of inositol triphosphate is usually transient because __________.

Once the kinase domain of receptor protein-tyrosine kinase has been activated,what does the activated receptor protein-tyrosine kinase do?

How is caspase-activated DNase (CAD)activated?

Which hormone is secreted by α\alphaα -cells in the pancreas in response to low blood glucose levels?

What is the largest protein superfamily encoded by animal genomes?

How is signaling by an activated G α\alphaα subunit terminated?

Why did the smooth muscle in cultured strips of aorta not respond to acetylcholine by relaxing,while the smooth muscle of aortic rings did?

What is the name of a calcium-binding protein that acts in conjunction with calcium to bring about the responses associated with cytoplasmic rises in calcium ion concentration?

Once activated,what does caspase-9 itself activate?

Why does rhodopsin have an unusually stable structure for a GPCR?

How do cells in the body of a multicellular organism usually communicate with each other?

Specificity in MAP kinase pathways is sometimes achieved by spatial localization of the pathway's component proteins.Spatial localization of these components is done by structural (i.e.,nonenzymatic)proteins called _____________.

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics,enzymes and Metabolism

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

Which heterotrimeric G proteins couple receptors to adenylyl cyclase via the activation of GTP-bound G _$\alpha$ subunits?

Which hormone is secreted by $\alpha$ -cells in the pancreas in response to low blood glucose levels?

How is signaling by an activated G _$\alpha$ subunit terminated?