Question 1

What is the general mechanism for signal transmission by 7TM receptors?

Accepted Answer

The receptors "snake" through a membrane

Question 2

EGF signaling is terminated by the action of phosphatases and the hydrolysis of bound _____________ by Ras.

Accepted Answer

The answer of EGF signaling is terminated by the action...

Question 3

The ________ receptor is approximately 50% identical in amino acid sequence with the EGF receptor and has similar domain structure, but it does not bind any known ligand.

Accepted Answer

The answer of The ________ receptor is approximately 50% identical...

Question 4

Why is bound GTP considered a "clock"?

Accepted Answer

A)  It is always produced and degraded in specific time intervals. 
B)  It is regulated by energy. 
C)  The G $\alpha$ receptors have intrinsic GTPase activity, hydrolyzing GTP to GDP and Pi. 
D)  It spontaneously hydrolyzes in the binding site of G proteins. 
E)  None of the answers is correct. 
A)  It is always produced and degraded in specific time intervals. 
B)  It is regulated by energy. 
C)  The G $\alpha$ receptors have intrinsic GTPase activity, hydrolyzing GTP to GDP and Pi. 
D)  It spontaneously hydrolyzes in the binding site of G proteins. 
E)  None of the answers is correct.

Question 5

What enzyme catalyzes the cleavage of PIP2?

Accepted Answer

A)  phospholipase A 
B)  phospholipase C 
C)  phospholipase D 
D)  phospholipase P 
E)  None of the answers is correct. 
A)  phospholipase A 
B)  phospholipase C 
C)  phospholipase D 
D)  phospholipase P 
E)  None of the answers is correct.

Question 6

Which of the following is the inactive form of protein kinase A?

Accepted Answer

A)  R2C2 
B)  R4C2 
C)  R2C4 
D)  R4C4 
E)  None of the answers is correct. 
A)  R2C2 
B)  R4C2 
C)  R2C4 
D)  R4C4 
E)  None of the answers is correct.

Question 7

_______________________ binds to the extracellular side of β-adrenergic receptors.

Accepted Answer

The answer of _______________________ binds to the extracellular side of...

Question 8

What is covalently attached to the $\alpha$and $\gamma$ subunits of heterotrimeric G proteins in order to anchor the protein to the cell membrane?

Accepted Answer

A)  galactose 
B)  N-acetylgalactosamine 
C)  cholesterol 
D)  phosphatidyl serine 
E)  fatty acid 
A)  galactose 
B)  N-acetylgalactosamine 
C)  cholesterol 
D)  phosphatidyl serine 
E)  fatty acid

Question 9

Describe two roles of phosphatidylinositol 4,5-bisphosphate (PIP2) in signal transduction.

Accepted Answer

1. PIP₂ is one of the signal molecules in

Question 10

Input from several signaling pathways is called _____________________.

Accepted Answer

The answer of Input from several signaling pathways is called...

Question 11

How is calmodulin activated?

Accepted Answer

A)  by binding both calcium and potassium 
B)  by binding Ca2+ when the cytosolic concentration is greater than 500 nM 
C)  by binding to a positively charged helix on another protein 
D)  by binding Ca2+ only when calcium channels are open, allowing Ca2+ efflux from the cell 
E)  None of the answers is correct. 
A)  by binding both calcium and potassium 
B)  by binding Ca2+ when the cytosolic concentration is greater than 500 nM 
C)  by binding to a positively charged helix on another protein 
D)  by binding Ca2+ only when calcium channels are open, allowing Ca2+ efflux from the cell 
E)  None of the answers is correct.

Question 12

Which of the following is an example of a disease that is caused by altered G-protein activity?

Accepted Answer

A)  whooping cough 
B)  cholera 
C)  bubonic plague 
D)  whooping cough and cholera 
E)  whooping cough and bubonic plague 
A)  whooping cough 
B)  cholera 
C)  bubonic plague 
D)  whooping cough and cholera 
E)  whooping cough and bubonic plague

Question 13

Which form of the guanyl nucleotide is bound to a G protein in its unactivated state?

Accepted Answer

A)  GTP 
B)  GDP 
C)  GMP 
D)  dGTP 
E)  None of the answers is correct. 
A)  GTP 
B)  GDP 
C)  GMP 
D)  dGTP 
E)  None of the answers is correct.

Question 14

____________ is the membrane protein that catalyzes the conversion of ATP to cAMP.

Accepted Answer

The answer of ____________ is the membrane protein that catalyzes...

Question 15

Important second messengers include cAMP, cGMP, calcium ion, _______________________, and diacylglycerol.

Accepted Answer

inositol 1

Question 16

What is a gene that leads to the transformation of susceptible cell types into cell types with cancer-like characteristics?

Accepted Answer

A)  protogene 
B)  retrogene 
C)  epigene 
D)  oncogene 
E)  None of the answers is correct. 
A)  protogene 
B)  retrogene 
C)  epigene 
D)  oncogene 
E)  None of the answers is correct.

Question 17

The enzyme responsible for induction of the phosphoinositide cascade is

Accepted Answer

A)  phospholipase C. 
B)  phospholipase A. 
C)  C-dependent protein (CDP). 
D)  calmodulin. 
E)  None of the answers is correct. 
A)  phospholipase C. 
B)  phospholipase A. 
C)  C-dependent protein (CDP). 
D)  calmodulin. 
E)  None of the answers is correct.

Question 18

Advantages of second messengers include

Accepted Answer

A)  the signal can be amplified by making many second messengers. 
B)  second messengers can freely diffuse to other sites within the cell. 
C)  a few common second messengers can be used in multiple signaling pathways. 
D)  All of the answers are correct. 
E)  A and C. 
A)  the signal can be amplified by making many second messengers. 
B)  second messengers can freely diffuse to other sites within the cell. 
C)  a few common second messengers can be used in multiple signaling pathways. 
D)  All of the answers are correct. 
E)  A and C.

Question 19

Which of the following amino acids can be phosphorylated?

Accepted Answer

A)  Tyr, Ser, Thr 
B)  Tyr, Ser, Trp 
C)  Ser, Thr, Asn 
D)  His, Ser, Phe 
E)  Tyr, Met, Trp 
A)  Tyr, Ser, Thr 
B)  Tyr, Ser, Trp 
C)  Ser, Thr, Asn 
D)  His, Ser, Phe 
E)  Tyr, Met, Trp

Question 20

How many 7TM membranes exist? What are some of their functions?

Accepted Answer

There are estimated to be thousands of 7

Exam 14: Signal-Transduction Pathways

What is the general mechanism for signal transmission by 7TM receptors?

EGF signaling is terminated by the action of phosphatases and the hydrolysis of bound _____________ by Ras.

The ________ receptor is approximately 50% identical in amino acid sequence with the EGF receptor and has similar domain structure, but it does not bind any known ligand.

Why is bound GTP considered a "clock"?

What enzyme catalyzes the cleavage of PIP2?

Which of the following is the inactive form of protein kinase A?

_______________________ binds to the extracellular side of β-adrenergic receptors.

What is covalently attached to the α\alphaα and γ\gammaγ subunits of heterotrimeric G proteins in order to anchor the protein to the cell membrane?

Describe two roles of phosphatidylinositol 4,5-bisphosphate (PIP2) in signal transduction.

Input from several signaling pathways is called _____________________.

How is calmodulin activated?

Which of the following is an example of a disease that is caused by altered G-protein activity?

Which form of the guanyl nucleotide is bound to a G protein in its unactivated state?

____________ is the membrane protein that catalyzes the conversion of ATP to cAMP.

Important second messengers include cAMP, cGMP, calcium ion, _______________________, and diacylglycerol.

What is a gene that leads to the transformation of susceptible cell types into cell types with cancer-like characteristics?

The enzyme responsible for induction of the phosphoinositide cascade is

Advantages of second messengers include

Which of the following amino acids can be phosphorylated?

How many 7TM membranes exist? What are some of their functions?

Biochemistry: an Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Oxidative Phosphorylation

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Membrane Channels and Pumps

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Nucleotide Biosynthesis

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

DNA Replication, Repair, and Recombination

Rna Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

Drug Development

Filters

What enzyme catalyzes the cleavage of PIP₂?

What is covalently attached to the $\alpha$ and $\gamma$ subunits of heterotrimeric G proteins in order to anchor the protein to the cell membrane?

Describe two roles of phosphatidylinositol 4,5-bisphosphate (PIP₂) in signal transduction.