Question 1

Catalytic receptors

Accepted Answer

A)  Bind ligands on the surface membrane and alter substrates in the cytosolic
compartment 
B)  Are activated only by neurotransmitters 
C)  Are activated only by steroid hormones 
D)  Bind second messengers inside cells and alter substrates in the cytosol 
E)  Stimulate catabolism 
A)  Bind ligands on the surface membrane and alter substrates in the cytosolic
compartment 
B)  Are activated only by neurotransmitters 
C)  Are activated only by steroid hormones 
D)  Bind second messengers inside cells and alter substrates in the cytosol 
E)  Stimulate catabolism A

Question 2

The signaling mechanism that converts an electrical signal on the surface of the cell to a Ca2+ signal inside the cell is which of the following?

Accepted Answer

A)  Ligand-gated channels (especially glutamate receptors) 
B)  Ryanodine receptors 
C)  IP3 receptors 
D)  Voltage-gated Ca2+ channels 
E)  Calmodulin-dependent protein kinase 
A)  Ligand-gated channels (especially glutamate receptors) 
B)  Ryanodine receptors 
C)  IP3 receptors 
D)  Voltage-gated Ca2+ channels 
E)  Calmodulin-dependent protein kinase D

Question 3

The function of PKA in G smechanisms is to

Accepted Answer

A)  Alter the activity of target proteins by phosphorylating them at serine or threonine residues 
B)  Synthesize cAMP from ATP 
C)  Degrade cAMP 
D)  Activate proteins by directly binding to them 
E)  Catalyze the re-association of the $\alpha$ and $\beta$Ƴ subunits 
A)  Alter the activity of target proteins by phosphorylating them at serine or threonine residues 
B)  Synthesize cAMP from ATP 
C)  Degrade cAMP 
D)  Activate proteins by directly binding to them 
E)  Catalyze the re-association of the $\alpha$ and $\beta$Ƴ subunits A

Question 4

In a Gs mechanism, what enzyme is activated by the a subunit?

Accepted Answer

A)  GTP ase 
B)  Calmodulin-dependent protein kinase 
C)  Adenyly cyclase 
D)  Protein phosphatase 
E)  Both A and C are correct 
A)  GTP ase 
B)  Calmodulin-dependent protein kinase 
C)  Adenyly cyclase 
D)  Protein phosphatase 
E)  Both A and C are correct

Question 5

Turn off of a Gs mechanisms requires

Accepted Answer

A)  Activation of $\alpha$2 receptors 
B)  degradation of cAMP by cAMP phosphodiesterase 
C)  PKA activation 
D)  Protein phosphatase inhibition 
E)  Protein phosphorylation 
A)  Activation of $\alpha$2 receptors 
B)  degradation of cAMP by cAMP phosphodiesterase 
C)  PKA activation 
D)  Protein phosphatase inhibition 
E)  Protein phosphorylation

Question 6

Nuclear receptors that alter gene expression bind to

Accepted Answer

A)  mRNA polymerase II 
B)  Response elements on the DNA 
C)  Introns 
D)  Exons 
E)  G-protein coupled receptors 
A)  mRNA polymerase II 
B)  Response elements on the DNA 
C)  Introns 
D)  Exons 
E)  G-protein coupled receptors

Question 7

Increases in cytosolic [Ca2+] can be involved in the signaling of all of the following EXCEPT

Accepted Answer

A)  Stimulus-secretion coupling 
B)  Excitation-contraction coupling 
C)  Excitation-synthesis coupling 
D)  Calmodulin-dependent signaling 
E)  Direct activation of enzymes 
A)  Stimulus-secretion coupling 
B)  Excitation-contraction coupling 
C)  Excitation-synthesis coupling 
D)  Calmodulin-dependent signaling 
E)  Direct activation of enzymes

Question 8

Increased cytosolic [Ca2+] involved in signaling can originate from

Accepted Answer

A)  Influx from the extracellular fluid through channels on the plasma membrane 
B)  Efflux from the mitochondria into the cytosol 
C)  Efflux from stores in the endoplasmic reticulum through RyR or IP3 receptors 
D)  Release from binding sites within the cytosol 
E)  A and C are correct 
A)  Influx from the extracellular fluid through channels on the plasma membrane 
B)  Efflux from the mitochondria into the cytosol 
C)  Efflux from stores in the endoplasmic reticulum through RyR or IP3 receptors 
D)  Release from binding sites within the cytosol 
E)  A and C are correct

Question 9

The step immediately following the binding of aligand to a G -protein coupled receptor is

Accepted Answer

A)  Dissociation of the a subunit from the $\beta$ and Ƴ subunit 
B)  Activation of some protein by the a subunit 
C)  Exchange of GTP for GDP on the a subunit 
D)  Hydrolysis of GTP by the a subunit 
E)  Exchange of GTP for GDP on the $\beta$Ƴ subunit 
A)  Dissociation of the a subunit from the $\beta$ and Ƴ subunit 
B)  Activation of some protein by the a subunit 
C)  Exchange of GTP for GDP on the a subunit 
D)  Hydrolysis of GTP by the a subunit 
E)  Exchange of GTP for GDP on the $\beta$Ƴ subunit

Question 10

IP3 in signaling mechanisms

Accepted Answer

A)  Is released form phosphatidylinositol bisphosphate in the plasma membrane 
B)  Is synthesized from inositol bisphosphate in the cytosol 
C)  Bind s to IP3 receptors on the ER, causing an Increase in cytosolic [Ca2+ ] 
D)  Is the main signaling chemical in Gs m echanisms 
E)  Both A and C are correct 
A)  Is released form phosphatidylinositol bisphosphate in the plasma membrane 
B)  Is synthesized from inositol bisphosphate in the cytosol 
C)  Bind s to IP3 receptors on the ER, causing an Increase in cytosolic [Ca2+ ] 
D)  Is the main signaling chemical in Gs m echanisms 
E)  Both A and C are correct

Question 11

Small molecular weight lipophilic hormones usually

Accepted Answer

A)  Bind to surface molecules and act through G-protein coupled receptors 
B)  Bind to cytosolic or nuclear receptors and alter gene expression 
C)  Bind to catalytic receptors on the surfaces of cells 
D)  Directly activate channels on the surface membrane 
E)  Bind to surface molecules and act through the JAK-STAT pathway 
A)  Bind to surface molecules and act through G-protein coupled receptors 
B)  Bind to cytosolic or nuclear receptors and alter gene expression 
C)  Bind to catalytic receptors on the surfaces of cells 
D)  Directly activate channels on the surface membrane 
E)  Bind to surface molecules and act through the JAK-STAT pathway

Question 12

The fastest way to get a signal from one place to another in the body is through

Accepted Answer

A)  Endocrine signals moving through the blood 
B)  Paracrine signaling molecules diffusing through the ECF 
C)  Action potentials moving along axons 
D)  Mechanical signals 
E)  Chemical signals moving along axons 
A)  Endocrine signals moving through the blood 
B)  Paracrine signaling molecules diffusing through the ECF 
C)  Action potentials moving along axons 
D)  Mechanical signals 
E)  Chemical signals moving along axons

Question 13

W hich of the following receptors DO NOT alter cAMP levels as a major mechanism of action

Accepted Answer

A)  β1 receptors 
B)  β2 receptors 
C)  α1 receptors 
D)  α2 receptors 
E)  M2 receptors 
A)  β1 receptors 
B)  β2 receptors 
C)  α1 receptors 
D)  α2 receptors 
E)  M2 receptors

Question 14

A signaling molecule that is secreted into the blood and carried by the  blood to distant target cells is said to be

Accepted Answer

A)  Autocrine 
B)  Paracrine 
C)  Endocrine 
D)  Neurocine 
E)  Neural 
A)  Autocrine 
B)  Paracrine 
C)  Endocrine 
D)  Neurocine 
E)  Neural

Question 15

Increasing cytosolic [Ca2+] is more useful as a signaling mechanism than Increasing [Na+] or [K +] or [Cl-] because

Accepted Answer

A)  Far fewer Ca2+ ions need to flow because intracellular [Ca2+] is so low 
B)  Ca2+ can bind to specific proteins 
C)  Unlike the other ions, Ca2+ can activate phosphorylation of proteins 
D)  The Increase in [Ca2+] can be short-lived 
E)  All of the above 
A)  Far fewer Ca2+ ions need to flow because intracellular [Ca2+] is so low 
B)  Ca2+ can bind to specific proteins 
C)  Unlike the other ions, Ca2+ can activate phosphorylation of proteins 
D)  The Increase in [Ca2+] can be short-lived 
E)  All of the above

Question 16

A signaling molecule that influences cells nearby the secreting cell is said to be

Accepted Answer

A)  Autocrine 
B)  Paracrine 
C)  Endocrine 
D)  Neurocine 
E)  Neural 
A)  Autocrine 
B)  Paracrine 
C)  Endocrine 
D)  Neurocine 
E)  Neural

Question 17

Turning off a G-protein coupled receptor requires

Accepted Answer

A)  Dissociation of the ligand from the receptor 
B)  Hydrolysis of GTP by the $\alpha$ subunit 
C)  Re-association of the $\alpha$ subunit with the $\beta$Ƴ subunit 
D)  Return of the activated proteins to their basal state 
E)  All of the above 
A)  Dissociation of the ligand from the receptor 
B)  Hydrolysis of GTP by the $\alpha$ subunit 
C)  Re-association of the $\alpha$ subunit with the $\beta$Ƴ subunit 
D)  Return of the activated proteins to their basal state 
E)  All of the above

Question 18

Increase in IP3 levels is associate with

Accepted Answer

A)  Gs mechanims 
B)  Gi mechanisms 
C)  Gq mechanisms 
D)  Go mechanisms 
E)  A and C are correct 
A)  Gs mechanims 
B)  Gi mechanisms 
C)  Gq mechanisms 
D)  Go mechanisms 
E)  A and C are correct

Question 19

Ligand-gated channels

Accepted Answer

A)  Are located only on post-synaptic membranes 
B)  Are located only on pre-synaptic membranes 
C)  Change their conductances upon ligand binding 
D)  Bind only high molecular weight proteins 
E)  Conduct on ly Na+ or K+ 
A)  Are located only on post-synaptic membranes 
B)  Are located only on pre-synaptic membranes 
C)  Change their conductances upon ligand binding 
D)  Bind only high molecular weight proteins 
E)  Conduct on ly Na+ or K+

Question 20

The function o f cAMP in Gs mechanisms is to

Accepted Answer

A)  Activate PKA 
B)  Activate calmodulin-dependent protein kinase 
C)  Inhibit protein phosphatases 
D)  Bind to the $\alpha$ subunit 
E)  Bind to the $\beta$Ƴ subunit 
A)  Activate PKA 
B)  Activate calmodulin-dependent protein kinase 
C)  Inhibit protein phosphatases 
D)  Bind to the $\alpha$ subunit 
E)  Bind to the $\beta$Ƴ subunit

Exam 13: Cell Signaling

Catalytic receptors

The signaling mechanism that converts an electrical signal on the surface of the cell to a Ca2+ signal inside the cell is which of the following?

The function of PKA in G smechanisms is to

In a Gs mechanism, what enzyme is activated by the a subunit?

Turn off of a Gs mechanisms requires

Nuclear receptors that alter gene expression bind to

Increases in cytosolic [Ca2+] can be involved in the signaling of all of the following EXCEPT

Increased cytosolic [Ca2+] involved in signaling can originate from

The step immediately following the binding of aligand to a G -protein coupled receptor is

IP3 in signaling mechanisms

Small molecular weight lipophilic hormones usually

The fastest way to get a signal from one place to another in the body is through

W hich of the following receptors DO NOT alter cAMP levels as a major mechanism of action

A signaling molecule that is secreted into the blood and carried by the blood to distant target cells is said to be

Increasing cytosolic [Ca2+] is more useful as a signaling mechanism than Increasing [Na+] or [K +] or [Cl-] because

A signaling molecule that influences cells nearby the secreting cell is said to be

Turning off a G-protein coupled receptor requires

Increase in IP3 levels is associate with

Ligand-gated channels

The function o f cAMP in Gs mechanisms is to

Physical Foundations Ii: Electrical Force Potential Capacitance and Current

Chemical Foundations I: Chemical Energy and Intermolecular Forces

Chemical Foundations Ii: Concentration and Kinetics

Diffusion

Electrochemical Potential and Free Energy

Cell Structure

Dna and Protein Synthesis

Protein Structure

Biological Membranes

Passive Transport and Facilitated Diffusion

Active Transport: Pumps and Exchangers

Osmosis and Osmotic Pressure

ATP Production I: Glycolysis

Atp Production Ii: Tca Cycle and Oxidative Phosphorylation

Atp Production Iii: Fatty Acid Oxidation and Amino Acid Oxidation

Origin of the Membrane Potential

The Action Potential

Propagation of the Action Potential

Skeletal Muscle Mechanics

Contractile Mechanisms in Skeletal Muscle

Neuromuscular Junction and Ec Coupling

Muscle Energetics Fatigue and Training

Smooth Muscle

Organization of the Nervous System

Cells Synapses and Neurotransmitters

Cutaneous Sensory Systems

Spinal Reflexes

Balance and Control of Movement

the Chemical Senses

Hearing

Vision

Autonomic Nervous System

Overview of the Cv System and Blood

Plasma and Red Blood Cells

White Blood Cells and Inflammation

The Heart As a Pump

Cellular Basis of Cardiac Contractility

the Cardiac Function Curve

Vascular Function: Hemodynamics

Microcirculation and Solute Exchange

Regulation of Perfusion

Integration of Cardiac Output and Venous Return

Regulation of Arterial Pressure

Mechanics of Breathing

Lung Volumes and Airway Resistance

Gas Exchange in the Lung

Oxygen and Carbon Dioxide Transport

Acid Base Physiology I Bicarbonate Buffers and Respiratory Compensation

Control of Ventilation

Anatomy and Renal Overview

Glomerular Filtration

Tubular Reabsorption and Secretion

Concentration and Dilution of Urine

Mouth and Esophagus

The Stomach

Intestinal and Colonic Motility

Pancreatic and Biliary Secretion

Digestion and Absorption of the Macronutrients

Energy Balance and Regulation of Food Intake

The signaling mechanism that converts an electrical signal on the surface of the cell to a Ca²⁺ signal inside the cell is which of the following?

Increases in cytosolic [Ca²⁺] can be involved in the signaling of all of the following EXCEPT

Increased cytosolic [Ca²⁺] involved in signaling can originate from

IP₃ in signaling mechanisms

Increasing cytosolic [Ca²⁺] is more useful as a signaling mechanism than Increasing [Na⁺] or [K ⁺] or [Cl^-] because

Increase in IP₃ levels is associate with