Question 1

Apoptosis protects healthy "neighbours" from a dying cell by preventing

Accepted Answer

A) cell death spreading from one cell to the next via paracrine signals. 
B) lysosomal enzymes exiting the dying cell that would damage surrounding cells. 
C) release of cellular energy that would interfere with the neighbours' energy budget. 
D) bits of membrane from the dying cell merging with neighbours and bringing in foreign receptors. 
E) neighbouring cells activating immunological responses. 
A) cell death spreading from one cell to the next via paracrine signals. 
B) lysosomal enzymes exiting the dying cell that would damage surrounding cells. 
C) release of cellular energy that would interfere with the neighbours' energy budget. 
D) bits of membrane from the dying cell merging with neighbours and bringing in foreign receptors. 
E) neighbouring cells activating immunological responses. B

Question 2

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 C

Question 3

One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?

Accepted Answer

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

Question 4

Which of the following is characterized by molecules from an adjacent cell being released to interact with neighbouring cells by binding with surface receptors and opening ion channels?

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 5

In which of the following ways could signal transduction most probably be explored in research to treat cancer?

Accepted Answer

A) removal of serine/threonine phosphate acceptors from transduction pathways in colon ?pre-cancerous growths 
B) alteration of protein kinases in cell cycle regulation in order to slow cancer growth 
C) increase in calcium ion uptake into the cytoplasm in order to modulate the effects of environmental carcinogens 
D) expansion of the role of transduction inhibitors in the cells before they give rise to cancer 
E) increase in the concentration of phosphodiesterases in order to produce more AMP 
A) removal of serine/threonine phosphate acceptors from transduction pathways in colon ?pre-cancerous growths 
B) alteration of protein kinases in cell cycle regulation in order to slow cancer growth 
C) increase in calcium ion uptake into the cytoplasm in order to modulate the effects of environmental carcinogens 
D) expansion of the role of transduction inhibitors in the cells before they give rise to cancer 
E) increase in the concentration of phosphodiesterases in order to produce more AMP

Question 6

Which of the following is true for the signalling system in an animal cell that lacks the ability to produce GTP?

Accepted Answer

A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. 
B) It could activate only the epinephrine system. 
C) It would be able to carry out reception and transduction but would not be able to respond to a signal. 
D) It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. 
E) It would employ a transduction pathway directly from an external messenger. 
A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. 
B) It could activate only the epinephrine system. 
C) It would be able to carry out reception and transduction but would not be able to respond to a signal. 
D) It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. 
E) It would employ a transduction pathway directly from an external messenger.

Question 7

A molecule that specifically binds to another molecule (often a larger one)is known as a(n)

Accepted Answer

A) ligand. 
B) receptor. 
C) transcription factor. 
D) activator. 
E) scaffolding protein. 
A) ligand. 
B) receptor. 
C) transcription factor. 
D) activator. 
E) scaffolding protein.

Question 8

Use this information to respond to the following questions.
Humans have receptors for two kinds of beta adrenergic compounds such as catecholamines to control cardiac muscle contractions. Some are beta 1 receptors that promote increased heart rate. Other drugs, called beta blockers, slow heart rate. Smooth muscle cells, however, have beta 2 receptors, which mediate muscle relaxation. Blockers of these effects are sometimes used to treat asthma.
-The use of beta 2 antagonist drugs may be useful in asthma because they may

Accepted Answer

A) increase constriction of the skeletal muscle of the chest wall. 
B) increase heart rate and therefore allow the patient to get more oxygen circulated. 
C) dilate the bronchioles by relaxing their smooth muscle. 
D) override the beta blockers that the patient is already taking. 
E) obstruct all G protein-mediated receptors. 
A) increase constriction of the skeletal muscle of the chest wall. 
B) increase heart rate and therefore allow the patient to get more oxygen circulated. 
C) dilate the bronchioles by relaxing their smooth muscle. 
D) override the beta blockers that the patient is already taking. 
E) obstruct all G protein-mediated receptors.

Question 9

Testosterone functions inside a cell by

Accepted Answer

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

Question 10

Use the following figure to answer the questions below.
  
-In the above diagram, the structure labelled A 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 11

Why has C. elegans proven to be a useful model for understanding apoptosis?

Accepted Answer

A) The animal has as many genes as complex organisms, but finding those responsible is easier than in a more complex organism. 
B) The nematode undergoes a fixed and easy-to-visualize number of apoptotic events during its normal development. 
C) This plant has a long-studied aging mechanism that has made understanding its death just a last stage. 
D) While the organism ages, its cells die progressively until the whole organism is dead. 
E) All of its genes are constantly being expressed so all of its proteins are available from each cell. 
A) The animal has as many genes as complex organisms, but finding those responsible is easier than in a more complex organism. 
B) The nematode undergoes a fixed and easy-to-visualize number of apoptotic events during its normal development. 
C) This plant has a long-studied aging mechanism that has made understanding its death just a last stage. 
D) While the organism ages, its cells die progressively until the whole organism is dead. 
E) All of its genes are constantly being expressed so all of its proteins are available from each cell.

Question 12

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 13

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 14

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 15

Sutherland discovered that epinephrine signals

Accepted Answer

A) a decrease in levels of cAMP as a result of bypassing the plasma membrane. 
B) lower blood glucose by binding to liver cells. 
C) interactions with insulin inside muscle cells. 
D) interactions directly with glycogen phosphorylase. 
E) elevation of cytosolic concentrations of cyclic AMP. 
A) a decrease in levels of cAMP as a result of bypassing the plasma membrane. 
B) lower blood glucose by binding to liver cells. 
C) interactions with insulin inside muscle cells. 
D) interactions directly with glycogen phosphorylase. 
E) elevation of cytosolic concentrations of cyclic AMP.

Question 16

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 17

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 18

Apoptosis involves all but which of the following?

Accepted Answer

A) fragmentation of the DNA 
B) cell-signalling pathways 
C) activation of cellular enzymes 
D) lysis of the cell 
E) digestion of cellular contents by scavenger cells 
A) fragmentation of the DNA 
B) cell-signalling pathways 
C) activation of cellular enzymes 
D) lysis of the cell 
E) digestion of cellular contents by scavenger cells

Question 19

Using the yeast signal transduction pathways, both types of mating cells release the mating factors. These factors bind to specific receptors on the correct cells

Accepted Answer

A) which induce changes in the cells that lead to cell fusion. 
B) which produce more of the a factor in a positive feedback. 
C) then one cell nucleus binds the mating factors and produces a new nucleus in the opposite cell. 
D) stimulating cell membrane disintegration, releasing the mating factors that lead to new yeast cells. 
E) which in turn releases a growth factor that stimulates mitosis in both cells. 
A) which induce changes in the cells that lead to cell fusion. 
B) which produce more of the a factor in a positive feedback. 
C) then one cell nucleus binds the mating factors and produces a new nucleus in the opposite cell. 
D) stimulating cell membrane disintegration, releasing the mating factors that lead to new yeast cells. 
E) which in turn releases a growth factor that stimulates mitosis in both cells.

Question 20

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.

Exam 11: Cell Communication

Apoptosis protects healthy "neighbours" from a dying cell by preventing

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?

One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?

Which of the following is characterized by molecules from an adjacent cell being released to interact with neighbouring cells by binding with surface receptors and opening ion channels?

In which of the following ways could signal transduction most probably be explored in research to treat cancer?

Which of the following is true for the signalling system in an animal cell that lacks the ability to produce GTP?

A molecule that specifically binds to another molecule (often a larger one)is known as a(n)

Testosterone functions inside a cell by

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

Why has C. elegans proven to be a useful model for understanding apoptosis?

In yeast signal transduction, the yeast cells

Sutherland discovered that epinephrine signals

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

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

Apoptosis involves all but which of the following?

Using the yeast signal transduction pathways, both types of mating cells release the mating factors. These factors bind to specific receptors on the correct cells

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

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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