Question 1

Which of the following is true during a typical cAMP-type signal transduction event?

Accepted Answer

A) The second messenger is the last part of the system to be activated. 
B) The hormone activates the second messenger by directly binding to it. 
C) The second messenger amplifies the hormonal response by attracting more hormones to the cell being affected. 
D) Adenylyl cyclase is activated after the hormone binds to the cell and before phosphorylation of proteins occurs. 
E) cAMP is waiting in the cell ready for the signal to be transduced. 
A) The second messenger is the last part of the system to be activated. 
B) The hormone activates the second messenger by directly binding to it. 
C) The second messenger amplifies the hormonal response by attracting more hormones to the cell being affected. 
D) Adenylyl cyclase is activated after the hormone binds to the cell and before phosphorylation of proteins occurs. 
E) cAMP is waiting in the cell ready for the signal to be transduced.

Question 2

Use the following figure to answer the questions below.
  
-In the above diagram,the structure labelled B is a(n)

Accepted Answer

A) transcription factor. 
B) activated relay molecule. 
C) ligand. 
D) plasma membrane receptor. 
E) intracellular receptor. 
A) transcription factor. 
B) activated relay molecule. 
C) ligand. 
D) plasma membrane receptor. 
E) intracellular receptor.

Question 3

Which of the following amino acids are most frequently phosphorylated by protein kinases in the cytoplasm during signal transduction?

Accepted Answer

A) tyrosines 
B) glycine and histidine 
C) serine and threonine 
D) glycine and glutamic acid 
E) Any of the 20 amino acids are equally phosphorylated. 
A) tyrosines 
B) glycine and histidine 
C) serine and threonine 
D) glycine and glutamic acid 
E) Any of the 20 amino acids are equally phosphorylated.

Question 4

If an adult person has a faulty version of the human analogue to ced-4 of the nematode,which of the following is most likely to result?

Accepted Answer

A) neurodegeneration 
B) activation of a developmental pathway found in the worm but not in humans 
C) a form of cancer in which there is insufficient apoptosis 
D) webbing of fingers or toes 
E) excess skin exfoliation 
A) neurodegeneration 
B) activation of a developmental pathway found in the worm but not in humans 
C) a form of cancer in which there is insufficient apoptosis 
D) webbing of fingers or toes 
E) excess skin exfoliation

Question 5

Use the following figure to answer the questions below.
  
-In the figure,the dots in the space between the two structures represent which of the following?

Accepted Answer

A) receptor molecules 
B) signal transducers 
C) neurotransmitters 
D) hormones 
E) pheromones 
A) receptor molecules 
B) signal transducers 
C) neurotransmitters 
D) hormones 
E) pheromones

Question 6

Use the following figure to answer the questions below.
  
-In the above diagram,the structure labelled C is a(n)

Accepted Answer

A) second messenger. 
B) activated relay molecule. 
C) ligand. 
D) receptor. 
E) phosphorylation cascade. 
A) second messenger. 
B) activated relay molecule. 
C) ligand. 
D) receptor. 
E) phosphorylation cascade.

Question 7

What does it mean to say that a signal is transduced?

Accepted Answer

A) The signal enters the cell directly and binds to a receptor inside. 
B) The physical form of the signal changes from one form to another. 
C) The signal is amplified, such than even a single molecule evokes a large response. 
D) The signal triggers a sequence of phosphorylation events inside the cell. 
E) This signal triggers dephosphorylation events inside the cell. 
A) The signal enters the cell directly and binds to a receptor inside. 
B) The physical form of the signal changes from one form to another. 
C) The signal is amplified, such than even a single molecule evokes a large response. 
D) The signal triggers a sequence of phosphorylation events inside the cell. 
E) This signal triggers dephosphorylation events inside the cell.

Question 8

Use the following figure to answer the questions below.
  
-Which of the following types of signalling is represented in the figure?

Accepted Answer

A) autocrine 
B) paracrine 
C) hormonal 
D) synaptic 
E) long-distance 
A) autocrine 
B) paracrine 
C) hormonal 
D) synaptic 
E) long-distance

Question 9

In yeast signal transduction,the yeast cells

Accepted Answer

A) must physically and directly interact. 
B) produce signal molecules that change themselves so they can interact with one another. 
C) produce response molecules that diffuse to other yeast cells. 
D) secrete molecules that result in response by other yeast cells. 
E) mate, after which the new cells secrete hybrid signals. 
A) must physically and directly interact. 
B) produce signal molecules that change themselves so they can interact with one another. 
C) produce response molecules that diffuse to other yeast cells. 
D) secrete molecules that result in response by other yeast cells. 
E) mate, after which the new cells secrete hybrid signals.

Question 10

Use this information to answer the following questions.
Affinity chromatography is a method that can be used to purify cell-surface receptors,while they retain their hormone-binding ability.A ligand (hormone)for a receptor of interest is chemically linked to polystyrene beads.A solubilized preparation of membrane proteins is passed over a column containing these beads.Only the receptor binds to the beads.
-This method of affinity chromatography would be expected to collect which of the following?

Accepted Answer

A) molecules of the hormone 
B) molecules of purified receptor 
C) G proteins 
D) assorted membrane proteins 
E) hormone-receptor complexes 
A) molecules of the hormone 
B) molecules of purified receptor 
C) G proteins 
D) assorted membrane proteins 
E) hormone-receptor complexes

Question 11

What is a G-protein receptor with GTP bound to it?

Accepted Answer

A) It is in its active state. 
B) It is signalling a protein to maintain its shape and conformation. 
C) It is using cGMP as a second messenger. 
D) It is directly affecting gene expression. 
E) It is non-functional. 
A) It is in its active state. 
B) It is signalling a protein to maintain its shape and conformation. 
C) It is using cGMP as a second messenger. 
D) It is directly affecting gene expression. 
E) It is non-functional.

Question 12

Use this information to answer the following questions.
A major group of G protein-coupled receptors contains seven transmembrane α helices.The amino end of the protein lies at the exterior of the plasma membrane.Loops of amino acids connect the helices either at the exterior face or on the cytosol face of the membrane.The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others.
-The coupled G protein most likely interacts with this receptor

Accepted Answer

A) at the NH₃ end. 
B) at the COO- end. 
C) along the exterior margin. 
D) along the interior margin. 
E) at the loop between H5 and H6. 
A) at the NH₃ end. 
B) at the COO- end. 
C) along the exterior margin. 
D) along the interior margin. 
E) at the loop between H5 and H6.

Question 13

Which of the following is characterized by hydrophobic molecules passing through the plasma membrane and interacting with cytosolic receptors?

Accepted Answer

A) hormonal signalling 
B) autocrine signalling 
C) paracrine signalling 
D) endocrine signalling 
E) synaptic signalling 
A) hormonal signalling 
B) autocrine signalling 
C) paracrine signalling 
D) endocrine signalling 
E) synaptic signalling

Question 14

What is most likely to happen to an animal's target cells that lack receptors for local regulators?

Accepted Answer

A) They might compensate by receiving nutrients via a factor. 
B) They could develop normally in response to neurotransmitters instead. 
C) They could divide but never reach full size. 
D) They might not be able to grow and multiply in response to growth factors from nearby cells. 
E) Cells do not need local regulators. 
A) They might compensate by receiving nutrients via a factor. 
B) They could develop normally in response to neurotransmitters instead. 
C) They could divide but never reach full size. 
D) They might not be able to grow and multiply in response to growth factors from nearby cells. 
E) Cells do not need local regulators.

Question 15

Of the following,a receptor protein in a membrane that recognizes a chemical signal is most similar to

Accepted Answer

A) the active site of an allosteric enzyme that binds to a specific substrate. 
B) tRNA specifying which amino acids are in a polypeptide. 
C) a metabolic pathway operating within a specific organelle. 
D) an enzyme having an optimum pH and temperature for activity. 
E) an antibody in the immune system. 
A) the active site of an allosteric enzyme that binds to a specific substrate. 
B) tRNA specifying which amino acids are in a polypeptide. 
C) a metabolic pathway operating within a specific organelle. 
D) an enzyme having an optimum pH and temperature for activity. 
E) an antibody in the immune system.

Question 16

Put the steps of the process of signal transduction in the order they occur:
1)A conformational change in the signal-receptor complex activates an enzyme.
2)Protein kinases are activated.
3)A signal molecule binds to a receptor.
4)Target proteins are phosphorylated.
5)Second messenger molecules are released.

Accepted Answer

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

Question 17

How does aldosterone function?

Accepted Answer

A) acts as a signal receptor that activates tyrosine kinases. 
B) binds with a receptor protein that enters the nucleus and activates specific genes. 
C) acts as a steroid signal receptor that activates ion channel proteins. 
D) becomes a second messenger that inhibits adenylyl cyclase. 
E) coordinates a phosphorylation cascade that increases spermatogenesis. 
A) acts as a signal receptor that activates tyrosine kinases. 
B) binds with a receptor protein that enters the nucleus and activates specific genes. 
C) acts as a steroid signal receptor that activates ion channel proteins. 
D) becomes a second messenger that inhibits adenylyl cyclase. 
E) coordinates a phosphorylation cascade that increases spermatogenesis.

Question 18

Which type of receptor in the plasma membrane reacts by forming dimers,adding phosphate groups,and then activating relay proteins?

Accepted Answer

A) G protein-coupled receptors 
B) ligand-gated ion channels 
C) steroid receptors 
D) receptor tyrosine kinases 
E) quorum sensing receptors 
A) G protein-coupled receptors 
B) ligand-gated ion channels 
C) steroid receptors 
D) receptor tyrosine kinases 
E) quorum sensing receptors

Question 19

Caffeine is an inhibitor of phosphodiesterase.Therefore,the cells of a person who has recently consumed coffee would have increased levels of

Accepted Answer

A) phosphorylated proteins. 
B) GTP. 
C) cAMP. 
D) adenylyl cyclase. 
E) activated G proteins. 
A) phosphorylated proteins. 
B) GTP. 
C) cAMP. 
D) adenylyl cyclase. 
E) activated G proteins.

Question 20

Use the following figure to answer the questions below.
  
-In the above diagram,the structure labelled D is a(n)

Accepted Answer

A) second messenger. 
B) activated relay molecule. 
C) ligand. 
D) receptor. 
E) phosphorylation cascade. 
A) second messenger. 
B) activated relay molecule. 
C) ligand. 
D) receptor. 
E) phosphorylation cascade.

Exam 11: Cell Communication

Which of the following is true during a typical cAMP-type signal transduction event?

Use the following figure to answer the questions below. -In the above diagram,the structure labelled B is a(n)

Which of the following amino acids are most frequently phosphorylated by protein kinases in the cytoplasm during signal transduction?

If an adult person has a faulty version of the human analogue to ced-4 of the nematode,which of the following is most likely to result?

Use the following figure to answer the questions below. -In the figure,the dots in the space between the two structures represent which of the following?

Use the following figure to answer the questions below. -In the above diagram,the structure labelled C is a(n)

What does it mean to say that a signal is transduced?

Use the following figure to answer the questions below. -Which of the following types of signalling is represented in the figure?

In yeast signal transduction,the yeast cells

What is a G-protein receptor with GTP bound to it?

Which of the following is characterized by hydrophobic molecules passing through the plasma membrane and interacting with cytosolic receptors?

What is most likely to happen to an animal's target cells that lack receptors for local regulators?

Of the following,a receptor protein in a membrane that recognizes a chemical signal is most similar to

How does aldosterone function?

Which type of receptor in the plasma membrane reacts by forming dimers,adding phosphate groups,and then activating relay proteins?

Caffeine is an inhibitor of phosphodiesterase.Therefore,the cells of a person who has recently consumed coffee would have increased levels of

Use the following figure to answer the questions below. -In the above diagram,the structure labelled D is a(n)

Introduction: Evolution and Themes of Biology

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

DNA Tools and Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure,Growth,and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons,Synapses,and Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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