Question 1

Which of the following is a unifying feature of polypeptide hormones?

Accepted Answer

A) originally synthesized without signal sequences 
B) synthesized as active prepro-hormones 
C) may produce several different peptide hormones with suitable processing 
D) activated from prepro-hormones to hormones by phosphorylation 
A) originally synthesized without signal sequences 
B) synthesized as active prepro-hormones 
C) may produce several different peptide hormones with suitable processing 
D) activated from prepro-hormones to hormones by phosphorylation

Question 2

Which of the following terms describes the members of the protein kinase C family that are regulated by Ca²⁺,diacylglycerol,and phosphatidylserine?

Accepted Answer

A) atypical PKCs 
B) conventional PKCs 
C) modified PKCs 
D) novel PKCs 
A) atypical PKCs 
B) conventional PKCs 
C) modified PKCs 
D) novel PKCs

Question 3

Which of the following explains how botulism toxin exerts its effect?

Accepted Answer

A) by inhibiting acetylcholinesterase 
B) by inhibiting acetylcholine release 
C) by stimulating acetylcholinesterase 
D) by opening ligand-gated ion channels 
A) by inhibiting acetylcholinesterase 
B) by inhibiting acetylcholine release 
C) by stimulating acetylcholinesterase 
D) by opening ligand-gated ion channels

Question 4

Which of the following mechanisms do steroid hormones such as glucocorticoids use to effect their action?

Accepted Answer

A) by binding to a plasma membrane receptor and then entering the cell 
B) by binding the plasma membrane receptor,which stimulates the receptor to enter the cell 
C) by entering into the cell and effecting the production of secondary messengers 
D) by entering into the cell and then acting as transcription regulators 
A) by binding to a plasma membrane receptor and then entering the cell 
B) by binding the plasma membrane receptor,which stimulates the receptor to enter the cell 
C) by entering into the cell and effecting the production of secondary messengers 
D) by entering into the cell and then acting as transcription regulators

Question 5

Which of the following receptor Cl- channels opens and contributes in part to the effects of ethanol on the brain?

Accepted Answer

A) glycine 
B) aspartate 
C) glutamate 
D) γ-aminobutyrate (GAB
A)  
A) glycine 
B) aspartate 
C) glutamate 
D) γ-aminobutyrate (GAB
A)

Question 6

Which of the following phospholipids is hydrolyzed to stimulate ceramide-activated protein kinase?

Accepted Answer

A) sphingomyelin 
B) phosphatidylinositol-4-phosphate 
C) phosphatidylcholine 
D) phosphatidylinositol 
A) sphingomyelin 
B) phosphatidylinositol-4-phosphate 
C) phosphatidylcholine 
D) phosphatidylinositol

Question 7

In G proteins,binding of GTP causes Gₐ dissociation.Which of the following effector proteins does it subsequently associate with?

Accepted Answer

A) adenylyl cyclase 
B) GTPase 
C) cAMP 
D) Gγ 
A) adenylyl cyclase 
B) GTPase 
C) cAMP 
D) Gγ

Question 8

Phosphorylation of Tyr⁵²⁷ in the SH₂ domain of protein tyrosine kinase pp60ᶜ⁻ˢʳᶜ inhibits tyrosine kinase activity.By which of the following mechanisms does it do this?

Accepted Answer

A) by moving an "activation loop" away from the active site 
B) by moving an "activation loop" into the active site 
C) by phosphorylating an "activation loop" 
D) by covalent linkage to an "activation loop" 
A) by moving an "activation loop" away from the active site 
B) by moving an "activation loop" into the active site 
C) by phosphorylating an "activation loop" 
D) by covalent linkage to an "activation loop"

Question 9

Which of the following is NOT a result of the phospholipase C activity mediated by hormone binding,signal transduction,and eventually Ca²⁺ release into the cytoplasm?

Accepted Answer

A) an increase in guanylyl cyclase activity 
B) the phosphorylation of specific proteins 
C) activation of protein kinases by calcium complexed with calmodulin 
D) the release of diacylglycerol from membrane phospholipids 
A) an increase in guanylyl cyclase activity 
B) the phosphorylation of specific proteins 
C) activation of protein kinases by calcium complexed with calmodulin 
D) the release of diacylglycerol from membrane phospholipids

Question 10

Hormones and other signal molecules bind with very high affinities to their receptors.At what concentrations are they produced in the body?

Accepted Answer

A) far above their KD values 
B) not more than twice their KD values 
C) equivalent to their KD values 
D) far below their KD values 
A) far above their KD values 
B) not more than twice their KD values 
C) equivalent to their KD values 
D) far below their KD values

Question 11

Rapid influx of Ca²⁺ into the cytoplasm can occur as a result of the binding of hormones to a receptor-activating phospholipase C activity.Which of the following does NOT contribute to the increased level of Ca²⁺?

Accepted Answer

A) lysozymes 
B) calciosomes 
C) endoplasmic reticulum 
D) extracellular stores through Ca²⁺ channels in the plasma membrane 
A) lysozymes 
B) calciosomes 
C) endoplasmic reticulum 
D) extracellular stores through Ca²⁺ channels in the plasma membrane

Question 12

Which of the following is a characteristic of calmodulin?

Accepted Answer

A) It contains only 1 helix-loop-helix motif that binds the Ca²⁺ ion. 
B) Its conformation is sensitive to Ca²⁺ binding. 
C) It contains a basic amphiphilic alpha helix that interacts with target proteins. 
D) It modulates the activity of only protein kinase A. 
A) It contains only 1 helix-loop-helix motif that binds the Ca²⁺ ion. 
B) Its conformation is sensitive to Ca²⁺ binding. 
C) It contains a basic amphiphilic alpha helix that interacts with target proteins. 
D) It modulates the activity of only protein kinase A.

Question 13

A muscarinic receptor is a subclass of acetylcholine receptor.Which of the following molecules inhibits the receptor?

Accepted Answer

A) muscarine 
B) acetylcholine 
C) GABA 
D) atropine 
A) muscarine 
B) acetylcholine 
C) GABA 
D) atropine

Question 14

Which of the following reasons explains why neurotransmitters must be removed from the synaptic cleft?

Accepted Answer

A) to promote prolonged stimulation of the postsynaptic cell 
B) to prevent prolonged stimulation of the presynaptic cell 
C) to promote prolonged stimulation of the presynaptic cell 
D) to prevent prolonged stimulation of the postsynaptic cell 
A) to promote prolonged stimulation of the postsynaptic cell 
B) to prevent prolonged stimulation of the presynaptic cell 
C) to promote prolonged stimulation of the presynaptic cell 
D) to prevent prolonged stimulation of the postsynaptic cell

Question 15

Which of the following is phospholipase C-γ homologous to with respect to the X and Y domains?

Accepted Answer

A) phospholipase C-β 
B) phospholipase C-α 
C) phospholipase A2 
D) phospholipase D 
A) phospholipase C-β 
B) phospholipase C-α 
C) phospholipase A2 
D) phospholipase D

Question 16

Which of the following is NOT involved in the generation of cancerous tumours?

Accepted Answer

A) mutations in several proto-oncogenes or tumour suppression genes 
B) interactions among 2 or more oncogene products 
C) simultaneous mutations in a proto-oncogene and only in 1 copy of a tumour suppression gene 
D) overlapping growth-control mechanisms such that,when one is compromised by mutation,others take over 
A) mutations in several proto-oncogenes or tumour suppression genes 
B) interactions among 2 or more oncogene products 
C) simultaneous mutations in a proto-oncogene and only in 1 copy of a tumour suppression gene 
D) overlapping growth-control mechanisms such that,when one is compromised by mutation,others take over

Question 17

Which of the following classes of tyrosine kinases classifies the insulin receptor?

Accepted Answer

A) Class I with 2 Cys-rich repeat sequences 
B) Class II with α2β2 tetrameric structure 
C) Class III with multiple immunoglobulin-like extracellular domains 
D) Class IV with a glycosylated protein domain 
A) Class I with 2 Cys-rich repeat sequences 
B) Class II with α2β2 tetrameric structure 
C) Class III with multiple immunoglobulin-like extracellular domains 
D) Class IV with a glycosylated protein domain

Question 18

Which of the following regarding neurons and the action potential is correct?

Accepted Answer

A) In myelinated axons,sodium channels are distributed evenly. 
B) Influx of K⁺ ions leads to a brief hyperpolarization of the cell membrane. 
C) The resting membrane potential is approximately -50 mV. 
D) Sodium ions that enter an axon through sodium channels in a given axonal region diffuse further along the axon,depolarizing the next axonal region. 
A) In myelinated axons,sodium channels are distributed evenly. 
B) Influx of K⁺ ions leads to a brief hyperpolarization of the cell membrane. 
C) The resting membrane potential is approximately -50 mV. 
D) Sodium ions that enter an axon through sodium channels in a given axonal region diffuse further along the axon,depolarizing the next axonal region.

Question 19

Which of the following components does a specific GTPase-activating protein bind to and activate?

Accepted Answer

A) the G protein 
B) the plasma membrane receptor 
C) adenylyl cyclase 
D) the Ras protein 
A) the G protein 
B) the plasma membrane receptor 
C) adenylyl cyclase 
D) the Ras protein

Question 20

Which of the following molecule(s)is increased in the brain as a result of a monoamine oxidase inhibitor acting as an antidepressant?

Accepted Answer

A) insulin 
B) tricyclics 
C) catecholamine 
D) tubulin 
A) insulin 
B) tricyclics 
C) catecholamine 
D) tubulin

Exam 11: The Reception and Transmission of Extracellular Information

Which of the following is a unifying feature of polypeptide hormones?

Which of the following terms describes the members of the protein kinase C family that are regulated by Ca²⁺,diacylglycerol,and phosphatidylserine?

Which of the following explains how botulism toxin exerts its effect?

Which of the following mechanisms do steroid hormones such as glucocorticoids use to effect their action?

Which of the following receptor Cl- channels opens and contributes in part to the effects of ethanol on the brain?

Which of the following phospholipids is hydrolyzed to stimulate ceramide-activated protein kinase?

In G proteins,binding of GTP causes Gₐ dissociation.Which of the following effector proteins does it subsequently associate with?

Phosphorylation of Tyr⁵²⁷ in the SH₂ domain of protein tyrosine kinase pp60ᶜ⁻ˢʳᶜ inhibits tyrosine kinase activity.By which of the following mechanisms does it do this?

Which of the following is NOT a result of the phospholipase C activity mediated by hormone binding,signal transduction,and eventually Ca²⁺ release into the cytoplasm?

Hormones and other signal molecules bind with very high affinities to their receptors.At what concentrations are they produced in the body?

Rapid influx of Ca²⁺ into the cytoplasm can occur as a result of the binding of hormones to a receptor-activating phospholipase C activity.Which of the following does NOT contribute to the increased level of Ca²⁺?

Which of the following is a characteristic of calmodulin?

A muscarinic receptor is a subclass of acetylcholine receptor.Which of the following molecules inhibits the receptor?

Which of the following reasons explains why neurotransmitters must be removed from the synaptic cleft?

Which of the following is phospholipase C-γ homologous to with respect to the X and Y domains?

Which of the following is NOT involved in the generation of cancerous tumours?

Which of the following classes of tyrosine kinases classifies the insulin receptor?

Which of the following regarding neurons and the action potential is correct?

Which of the following components does a specific GTPase-activating protein bind to and activate?

Which of the following molecule(s)is increased in the brain as a result of a monoamine oxidase inhibitor acting as an antidepressant?

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Lipid Biosynthesis

Membranes and Membrane Transport

Enzymes Kinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Nutrition and the Organization of Metabolism

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Nitrogen Acquisition and Amino Acid Metabolism

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Synthesis and Degradation of Nucleotides

Recombinant Dna: Cloning and Creation of Chimeric Genes

DNA Metabolism: Replication, recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Post-Transcriptional Regulation of Gene Expression

Completing the Protein Life Cycle: Folding, processing, and Degradation

Metabolic Integration and Organ Specialization

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