Question 1

Injecting fibroblasts with anti-Ras antibodies that inactivate Ras proteins increases cell division response to growth factors. 
__________________

Accepted Answer

A) True 
 B)False

Question 2

The outer part of the enzyme linked receptor has a binding site for a signaling molecule, and the part of the receptor that extends into the cytosol has a binding site for a specific G protein. 
__________________

Accepted Answer

A) True 
 B)False

Question 3

In what part of the cell does a polar signaling molecule bind its receptor? A nonpolar signaling molecule? Explain your reasoning.

Accepted Answer

Polar signaling molecules bind membrane

Question 4

Compare and contrast the signal transduction pathway involving cAMP with that involving phospholipids.

Accepted Answer

Concepts to Consider: Role of

Question 5

Insulin stimulates cells to take in glucose by facilitated diffusion, so insulin receptor-down regulation increases the ability of cells to take in glucose. 
__________________

Accepted Answer

A) True 
 B)False

Question 6

Phospholipase C catalyzes the reaction in which:

Accepted Answer

A)  PIP2 is split. 
B)  IP3 is converted to DAG. 
C)  a protein kinase is activated. 
D)  DAG is converted to PIP2. 
E)  calcium ions are released from the ER. 
A)  PIP2 is split. 
B)  IP3 is converted to DAG. 
C)  a protein kinase is activated. 
D)  DAG is converted to PIP2. 
E)  calcium ions are released from the ER.

Question 7

When signal molecules bind to two tyrosine kinase receptors, the receptors move closer to each other and form a monomer . __________________

Accepted Answer

A) True 
 B)False

Question 8

What enzyme splits a membrane phospholipid into inositol trisphosphate (IP3) and diacylglycerol (DAG)?

Accepted Answer

A)  phospholipase C 
B)  protein kinase C 
C)  adenylyl cyclase 
D)  protein kinase A 
E)  phosphodiesterase 
A)  phospholipase C 
B)  protein kinase C 
C)  adenylyl cyclase 
D)  protein kinase A 
E)  phosphodiesterase

Question 9

Which is an example of a second messenger?

Accepted Answer

A)  protein kinase A 
B)  an ion channel 
C)  cyclic AMP 
D)  GABA 
E)  insulin 
A)  protein kinase A 
B)  an ion channel 
C)  cyclic AMP 
D)  GABA 
E)  insulin

Question 10

Explain the differences between receptor up-regulation and down-regulation including the conditions under which a cell would use one rather than the other.

Accepted Answer

Concepts to Consider: Receptor

Question 11

Give some examples showing how cells respond to signals. How are signals terminated?

Accepted Answer

Concepts to Consider: Regulation of ion

Question 12

How many times do G protein-linked receptors loop back and forth through the plasma membrane?

Accepted Answer

A)  once 
B)  twice 
C)  three 
D)  seven 
E)  eleven 
A)  once 
B)  twice 
C)  three 
D)  seven 
E)  eleven

Question 13

Compare and contrast the structure and function of ion channel-linked receptors, G protein-linked receptors, and enzyme-linked receptors. In general, how do they differ from intracellular receptors?

Accepted Answer

Concepts to Consider: Ligand-g

Question 14

How are hormones produced by endocrine glands typically transported to target cells?

Accepted Answer

A)  in the blood 
B)  through the air 
C)  across a synapse 
D)  via direct contact 
E)  in interstitial fluid 
A)  in the blood 
B)  through the air 
C)  across a synapse 
D)  via direct contact 
E)  in interstitial fluid

Question 15

Which statement about Ras proteins is false ?

Accepted Answer

A)  They are G proteins. 
B)  They include MAP kinases. 
C)  They are active when bound to GTP. 
D)  They are inactivated when phosphorylated. 
E)  They are activated by tyrosine kinase receptors. 
A)  They are G proteins. 
B)  They include MAP kinases. 
C)  They are active when bound to GTP. 
D)  They are inactivated when phosphorylated. 
E)  They are activated by tyrosine kinase receptors.

Question 16

During enzyme-linked reception, signal molecules bind to two tyrosine kinase receptors. The receptor proteins move closer together in the plasma membrane and pair, forming a(n) ____.

Accepted Answer

A)  gate 
B)  dimer 
C)  pathway 
D)  polypeptide chain 
E)  protein kinase cascade 
A)  gate 
B)  dimer 
C)  pathway 
D)  polypeptide chain 
E)  protein kinase cascade

Question 17

Adenylyl cyclase catalyzes the reaction in which:

Accepted Answer

A)  PIP2 is split. 
B)  ATP is converted to cAMP. 
C)  GTP is converted to GDP. 
D)  a protein is phosphorylated. 
E)  calcium ions bind calmodulin. 
A)  PIP2 is split. 
B)  ATP is converted to cAMP. 
C)  GTP is converted to GDP. 
D)  a protein is phosphorylated. 
E)  calcium ions bind calmodulin.

Question 18

You conduct an experiment in which you inactivate Ras proteins in fibroblast cells. Which of the following is the most immediate consequence of this procedure?

Accepted Answer

A)  The fibroblasts divide uncontrollably. 
B)  The fibroblasts synthesize excess DAG. 
C)  The fibroblasts synthesize excess G protein. 
D)  The fibroblasts no longer respond to calmodulin. 
E)  The fibroblasts no longer synthesize DNA in response to growth factors. 
A)  The fibroblasts divide uncontrollably. 
B)  The fibroblasts synthesize excess DAG. 
C)  The fibroblasts synthesize excess G protein. 
D)  The fibroblasts no longer respond to calmodulin. 
E)  The fibroblasts no longer synthesize DNA in response to growth factors.

Question 19

What happens when Ras proteins become stuck in their "on" state?

Accepted Answer

A)  Cellar responses are slowed. 
B)  Additional ions are catalyzed. 
C)  There is unregulated cell division. 
D)  There is an increase in protein synthesis. 
E)  Ligand-gated channels close off the membrane. 
A)  Cellar responses are slowed. 
B)  Additional ions are catalyzed. 
C)  There is unregulated cell division. 
D)  There is an increase in protein synthesis. 
E)  Ligand-gated channels close off the membrane.

Question 20

What is the process in which one activated receptor can give rise to thousands of final products?

Accepted Answer

A)  signal transcription 
B)  signal transmission 
C)  signal transduction 
D)  signal termination 
E)  signal amplification 
A)  signal transcription 
B)  signal transmission 
C)  signal transduction 
D)  signal termination 
E)  signal amplification

Exam 6: Cell Communication

Injecting fibroblasts with anti-Ras antibodies that inactivate Ras proteins increases cell division response to growth factors. __________________

The outer part of the enzyme linked receptor has a binding site for a signaling molecule, and the part of the receptor that extends into the cytosol has a binding site for a specific G protein. __________________

In what part of the cell does a polar signaling molecule bind its receptor? A nonpolar signaling molecule? Explain your reasoning.

Compare and contrast the signal transduction pathway involving cAMP with that involving phospholipids.

Insulin stimulates cells to take in glucose by facilitated diffusion, so insulin receptor-down regulation increases the ability of cells to take in glucose. __________________

Phospholipase C catalyzes the reaction in which:

When signal molecules bind to two tyrosine kinase receptors, the receptors move closer to each other and form a monomer . __________________

What enzyme splits a membrane phospholipid into inositol trisphosphate (IP3) and diacylglycerol (DAG)?

Which is an example of a second messenger?

Explain the differences between receptor up-regulation and down-regulation including the conditions under which a cell would use one rather than the other.

Give some examples showing how cells respond to signals. How are signals terminated?

How many times do G protein-linked receptors loop back and forth through the plasma membrane?

Compare and contrast the structure and function of ion channel-linked receptors, G protein-linked receptors, and enzyme-linked receptors. In general, how do they differ from intracellular receptors?

How are hormones produced by endocrine glands typically transported to target cells?

Which statement about Ras proteins is false ?

During enzyme-linked reception, signal molecules bind to two tyrosine kinase receptors. The receptor proteins move closer together in the plasma membrane and pair, forming a(n) ____.

Adenylyl cyclase catalyzes the reaction in which:

You conduct an experiment in which you inactivate Ras proteins in fibroblast cells. Which of the following is the most immediate consequence of this procedure?

What happens when Ras proteins become stuck in their "on" state?

What is the process in which one activated receptor can give rise to thousands of final products?

A View of Life

Atoms and Molecules the Chemical Basis of Life

The Chemistry of Life Organic Compounds

Organization of the Cell

Biological Membranes

Energy and Metabolism

How Cells Make Atp Energy-Releasing Pathways

Photosynthesis Capturing Light Energy

Chromosomes, Mitosis, and Meiosis

The Basic Principles of Heredity

Dna the Carrier of Genetic Information

Gene Expression

Gene Regulation

Dna Technology and Genomics

Human Genetics and the Human Genome

Developmental Genetics

Introduction to Darwinian Evolution

Evolutionary Change in Populations

Speciation and Macroevolution

The Origin and Evolutionary History of Life

The Evolution of Primates

Understanding Diversity Systematics

Viruses and Subviral Agents

Bacteria and Archaea

Protists

Seedless Plants

Seed Plants

The Fungi

An Introduction to Animal Diversity

Sponges, Cnidarians, Ctenophores, and Protostomes

The Deuterostomes

Plant Structure Growth and Development

Leaf Structure and Function

Stem Structure and Transport

Roots and Mineral Nutrition

Reproduction in Flowering Plants

Plant Developmental Responses to External and Internal Signals

Animal Structure and Function an Introduction

Protection Support and Movement

Neural Signaling

Neural Regulation

Sensory Systems

Internal Transport

The Immune System Internal Defense

Gas Exchange

Processing Food and Nutrition

Osmoregulation and Disposal of Metabolic Wastes

Endocrine Regulation

Reproduction

Animal Development

Animal Behavior

Introduction to Ecology Population Ecology

Community Ecology

Ecosystems and the Biosphere

Ecology and the Geography of Life

Biological Diversity and Conservation Biology

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