Mcq’s Of Biochemistry set1 By Dr.Ravi at 8 February, 2010, 3:21 am

This is the first set of mcq’s for biochemistry.

All are based on protein synthesis mainly.

Each set will contain 10 mcqs so have a good time at Medical World

1. Amplification of a chemical signal occurs whena. a receptor in the plasma membrane activates several G– protein molecules while a signal molecule is bound to it.b. a cAMP molecule activates one protein kinase molecule before being converted to AMP.c. phosphorylase and phosphatase activities are balanced.d. receptor tyrosine kinases dimerize upon ligand binding.e. both a and d occur.

2. Which of the following provides the best evidence that cell–signaling pathways evolved early in the history of life?a. They are seen in “primitive” cells such as yeast.b. Yeast cells signal each other for mating.c. Signal transduction molecules found in distantly related organisms are similar.d. Signals can be sent long distances by cells.e. Most signals are received by cell surface receptors.

3. Consider this pathway: epinephrine → G–protein–linked receptor → G protein → adenylyl cyclase → cAMP. Identify the second messenger.a. cAMPb. G proteinc. GTPd. adenylyl cyclasee. G–protein–linked receptor

4. Which observation suggested to Sutherland the involvement of a second messenger in epinephrine′s effect on liver cells?a. Enzymatic activity was proportional to the amount of calcium added to a cell–free extract.b. Receptor studies indicated that epinephrine was a ligand.c. Glycogen breakdown was observed only when epinephrine was administered to intact cells.d. Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were

combined.e. Epinephrine was known to have different effects on different types of cells.

5. Binding of a signal molecule to which type of receptor leads directly to a change in the distribution of anions and/or cations on opposite sides of the membrane?a. receptor tyrosine kinaseb. G–protein–linked receptorc. phosphorylated receptor tyrosine kinase dimerd. ligand–gated ion channele. intracellular receptor

6. Protein phosphorylation is commonly involved with all of the following excepta. regulation of transcription by extracellular signal molecules.b. enzyme activation.c. activation of G–protein–linked receptors.d. activation of receptor tyrosine kinases.e. activation of protein kinase molecules.

7. Signal transduction pathways benefit cells for all of the following reasons excepta. they help cells respond to signal molecules that are too large or too polar to cross the plasma membrane.b. they enable different cells to respond appropriately to the same signal.c. they help cells use up phosphate generated by ATP breakdown.d. they can amplify a signal.e. variations in the signal transduction pathways can enhance response specificity.

8. Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction becausea. they are species specific.b. they always lead to the same cellular response.c. they amplify the original signal manyfold.d. they counter the harmful effects of phosphatases.e. the number of molecules used is small and fixed.

9. The activation of receptor tyrosine kinases is always characterized bya. dimerization and phosphorylation.b. IP3 binding.c. a phosphorylation cascade.d. GTP hydrolysis.e. channel protein conformational change.

10. Lipid–soluble signal molecules, such as testosterone, cross the membranes of all cells but affect only target cells becausea. only target cells retain the appropriate DNA segments.b. intracellular receptors are present only in target cells.c. most cells lack the Y chromosome required.

d. only target cells possess the cytosolic enzymes that transduce the testosterone.e. only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor.

Answers:1. A2. C3. A4. C5. D6. C7. C8. C9. A10. B

Chapter 04Instructions

Choose your answer by clicking the radio button next to your choice and then press 'Submit' to get your score.

Question 1

Which of the following statements is not true about receptors?

a) Most receptors are proteins situated in the cell membrane.

b) Receptors contain a hollow or cleft on their surface which is known

as a binding site.

c) Receptors bind chemical messengers such as neurotransmitters or

hormones.

d) Receptors catalyse reactions on chemical messengers.

Question 2

Which of the following statements is not true about neurotransmitters?

a) Neurotransmitters are released by nerves.

15

#Most receptors

b) Neurotransmitters are required to carry a 'message' from a nerve

to a target cell.

c) Neurotransmitters have significant distances to cover to reach their

target cells.

d) Neurotransmitters bind to receptors on target cells.

Question 3

Which of the following is not a neurotransmitter?

a) acetylcholine

b) cyclic AMP

c) noradrenaline

d) dopamine

Question 4

Which of the following statements is not true regarding the binding site of a receptor?

a) The binding site is normally a hollow or cleft in the surface of a

receptor.

b) The binding site is normally hydrophobic in nature.

c) Chemical messengers fit into binding sites and bind to functional

groups within the binding site.

d) The binding site contains amino acids which are important to the

binding process and a catalytic mechanism.

#Neurotransmitte

#acetylcholine#cy

Question 5

Which of the following statements is not true about a ligand-gated ion channel receptor?

a) Ligand-gated ion channel receptors are present in the cell

membrane.

b) Neurotransmitters can act as the chemical messengers for ligand-

gated ion channels.

c) Ligand-gated ion channels consist of five glycoproteins.

d) Differences in membrane potential affect whether ligand-gated ion

channel receptors open or close.

Question 6

Which of the following statements is true about a G-protein coupled receptor?

a) It contains five transmembrane hydrophobic sections.

b) There are more extracellular loops than intracellular loops.

c) The binding region for the G-protein involves two extracellular

loops.

d) The N-terminal chain is extracellular and the C-terminal chain is

intracellular.

#The binding site

#Ligand-gated ion

#It contains f ive t

Question 7

Which of the following is not a G-protein coupled receptor?

a) The muscarinic receptor.

b) The glycine receptor.

c) The adrenergic receptor.

d) The glutamate receptor.

Question 8

Which of the following statements is not true about G-protein coupled receptors?

a) They generally mediate the action of fast acting neurotransmitters.

b) They mediate the action of some hormones.

c) They activate signal proteins called G-proteins.

d) Histamine can act as a ligand for some G-protein coupled

receptors.

Question 9

Which of the following pairs of receptors are likely to show the greatest structural similarity?

a) The dopamine receptor subtypes D3 and D5.

b) The M2 muscarinic receptor and the β2-adrenergic receptor .

c) The H2 histamine receptor and the α1-adrenoceptor.

#The muscarinic

#They generally m

d) The H1histamine receptor and the β2 adrenoceptor.

Question 10

Which of the following pairs of receptors illustrates convergent evolution?

a) The D2 and D3-dopaminergic receptor subtypes.

b) The D4 and D5-dopaminergic receptor subtypes.

c) The β1 and β2-adrenoceptor subtypes.

d) The M3 and M5-muscarinic receptor subtypes.

Question 11

Which of the following reactions is catalysed by a protein kinase?

a) The phosphorylation of alcohol groups in protein substrates.

b) The hydrolysis of phosphate groups in protein substrates.

c) The phosphorylation of alcohol groups in carbohydrates.

d) The hydrolysis of phosphate groups in ATP and GTP.

Question 12

Which of the following statements is true about a tyrosine kinase linked receptor?

a) It is situated in the cytoplasm.

#The dopamine re

#The D<sub>2</s

#The phosphoryla

b) The N-terminal chain is intracellular.

c) The ligand binding site is in the N-terminal chain.

d) It has two hydrophobic transmembrane regions.

Question 13

Which of the following is not a typical messenger for a tyrosine kinase linked receptor?

a) insulin

b) acetylcholine

c) growth factors

d) cytokines

Question 14

Which of the following statements is true regarding intracellular receptors?

a) They consist of three protein subunits.

b) They contain a ligand binding site near the C-terminal end.

c) They contain a binding region for DNA near the N-terminal end.

d) They are activated by hydrophobic molecules which are

synthesised within the cell.

#It is situated in th

#insulin#acetylch

#They consist of

Question 15

Which of the following statements is true regarding the DNA binding region of intracellular receptors?

a) It contains five cysteine residues.

b) Four cysteine residues are involved in binding two zinc ions.

c) It identifies particular nucleotide sequences in DNA.

d) The DNA binding region is known as having 'thiol fingers'

Chapter 04Results

You have answered 0 out of 15 questions correctly.

Your percentage score is 0%.

Question 1

Which of the following statements is not true about receptors?

You did not answer the question.

Correct answer:

d) Receptors catalyse reactions on chemical messengers.

Feedback:

The binding site of receptors is analogous to the active site of enzymes. However, no reaction is catalysed. The ligand for the binding site acts as a chemical messenger. It binds and causes an induced fit that results in 'knock on effects' which lead to a message being received in the cell. Most receptors are present in the cell membrane although some are intracellular.Page reference: 42-45

Question 2

Which of the following statements is not true about neurotransmitters?

You did not answer the question.

Correct answer:

c)

Feedback:

The synaptic gap between a nerve and its target cell is very small and so neurotransmitters do not have a huge distance to travel to reach their target receptor.Page reference: 42-44

Question 3

Which of the following is not a neurotransmitter?

You did not answer the question.

Correct answer:

b) cyclic AMP

Feedback:

Cyclic AMP is a secondary messenger that is formed 'downstream' of a receptor activated process.Page reference: 42-44, 60

Question 4

Which of the following statements is not true regarding the binding site of a receptor?

You did not answer the question.

Correct answer:

d) The binding site contains amino acids which are important to the binding process and a catalytic mechanism.

Feedback:

Receptors do not catalyse reactions and so the binding site does not contain amino acids involved in a catalytic process.Page reference: 45-47

Question 5

Which of the following statements is not true about a ligand-gated ion channel receptor?

You did not answer the question.

Correct answer:

d) Differences in membrane potential affect whether ligand-gated ion channel receptors open or close.

Feedback:

Ligand-gated ion channels are controlled by ligands and not by the membrane potential. Voltage-gated ion channels are controlled by membrane potential.Page reference: 47-50

Question 6

Which of the following statements is true about a G-protein coupled receptor?

You did not answer the question.

Correct answer:

d) The N-terminal chain is extracellular and the C-terminal chain is intracellular.

Feedback:

Option a) is wrong since there are 7 transmembrane hydrophobic regions. Option b) is wrong since there are the same number of intracellular and extracellular loops. Option c) is wrong since the binding region of the G-protein involves one of the intracellular loops and the C-terminal chain.Page reference: 50-51

Question 7

Which of the following is not a G-protein coupled receptor?

You did not answer the question.

Correct answer:

b) The glycine receptor.

Feedback:

The glycine receptor is an ion channel.Page reference: 50-52,48

Question 8

Which of the following statements is not true about G-protein coupled receptors?

You did not answer the question.

Correct answer:

a) They generally mediate the action of fast acting neurotransmitters.

Feedback:

Fast acting neurotransmitters generally activate ion channels since the secondary effect is faster than that of G-protein coupled receptors.Page reference: 50-52

Question 9

Which of the following pairs of receptors are likely to show the greatest structural similarity?

You did not answer the question.

Correct answer:

c) The H2histamine receptor and the α1-adrenoceptor.

Feedback:

These receptors are closely related on the evolutionary tree of G-protein coupled receptors. The other pairings are more distantly related.Page reference: 51-52

Question 10

Which of the following pairs of receptors illustrates convergent evolution?

You did not answer the question.

Correct answer:

b) The D4 and D5-dopaminergic receptor subtypes.

Feedback:

Both these receptors bind dopamine, but they have evolved from different branches of the evolutionary tree. The other pairings are examples of divergent evolution since they have evolved from the same branch.Page reference: 51-52

Question 11

Which of the following reactions is catalysed by a protein kinase?

You did not answer the question.

Correct answer:

a) The phosphorylation of alcohol groups in protein substrates.

Feedback:

Protein kinase enzymes are responsible for catalysing phosphorylations of alcohol or phenol groups on protein substrates. The hydrolysis of phosphates is catalysed by phosphorylases and not by kinases. Carbohydrates contain alcohol functional groups, but these molecules are not proteins and do not act as substrates for protein kinases. Page reference: 53-55

Question 12

Which of the following statements is true about a tyrosine kinase linked receptor?

You did not answer the question.

Correct answer:

c) The ligand binding site is in the N-terminal chain.

Feedback:

Options a), b) and d) are false. The receptor is situated in the cell membrane. The N-terminal chain is extracellular and this is where the ligand binding site is. There is only one hydrophobic transmembrane region.Page reference: 53-55

Question 13

Which of the following is not a typical messenger for a tyrosine kinase linked receptor?

You did not answer the question.

Correct answer:

b) acetylcholine

Feedback:

Acetylcholine is a neurotransmitter that activates two types of cholinergic receptor, one of which is an ion channel and the other a G-protein coupled receptor. The other options are hormones that can catalyse various types of tyrosine kinase linked receptors.Page reference: 53-55

Question 14

Which of the following statements is true regarding intracellular receptors?

You did not answer the question.

Correct answer:

b) They contain a ligand binding site near the C-terminal end.

Feedback:

Statements a), c) and d) are false. Intracellular receptors are single proteins. They contain a binding region for DNA near the middle of the protein and they are activated by hydrophobic molecules which are extracellular messengers and cross the cell membrane to reach their target. Page reference: 55-56

Question 15

Which of the following statements is true regarding the DNA binding region of intracellular receptors?

You did not answer the question.

Correct answer:

c) It identifies particular nucleotide sequences in DNA.

Feedback:

Statements a), b) and d) are false. The DNA binding region of intracellular receptors contains nine cysteine residues, eight of which are involved in binding two zinc ions. The DNA binding region is known as the zinc finger domains.Page reference: 55-56

Chapter 05Instructions

Choose your answer by clicking the radio button next to your choice and then press 'Submit' to get your score.

Question 1

Which of the following reactions is catalyzed by the enzyme adenylate cyclase?

a) The conversion of ATP to cyclic AMP.

b) The conversion of cyclic AMP to AMP.

c) The conversion of cyclic AMP to ATP.

d) The conversion of AMP to cyclic AMP.

10

#The conversion

Question 2

What is the product, indicated by the letter C in the following diagram?

a) inositol triphosphate

b) diacylglycerol

c) inositol diphosphate

d) phosphatidylinositol diphosphate

Question 3

Which of the following statements is true for diacylglycerol (DG) formed in the following reaction?

#inositol triphosph

a) It is a hydrophobic molecule.

b) It moves into the cytoplasm.

c) It deactivates an enzyme called protein kinase C.

d) It is not a secondary messenger.

Question 4

Which of the following statements is true for inositol triphosphate (IP3) formed in the reaction below?

#It is a hydrophob

a) It is a hydrophobic molecule.

b) It moves into the cytoplasm.

c) It deactivates the release of calcium ions.

d) It is not a secondary messenger.

Question 5

Which of the following statements is untrue about G-proteins?

a) G-proteins consist of four protein subunits.

b) G-Proteins act as signal proteins.

c) G-Proteins interact with receptors.

d) G-Proteins bind GDP in the resting state.

#It is a hydrophob

#G-proteins cons

Question 6

Which of the following is true when a G-protein interacts with a receptor?

a) The G-protein is split into a γ-subunit and an α, β-dimer

b) The G-protein is split into a β-subunit and an α, γ-dimer

c) The G-protein is split into an α-subunit and a β, γ-dimer

d) The G-protein is split into its component protein subunits

Question 7

Which of the following subunits activates adenylate cyclase?

a) The αi-subunit

b) The αs-subunit

c) The αq-subunit

d) The αo-subunit

Question 8

Which of the following is untrue with respect to small G-proteins?

a) Small G-proteins consist of a single protein.

b) Ras is an example of a small G-protein.

c) Small G-proteins bind GDP in the resting state.

d) Small G-proteins are the same as G-proteins, but have a lower

molecular weight.

#The G-protein is

#The a<sub>i</su

Question 9

Which of the following statements best explains the action of lithium salts in treating manic depressive illness?

a) They inhibit adenylate cyclase.

b) They inhibit phospholipase C.

c) They inhibit protein kinase C.

d) They inhibit a phosphatase enzyme.

Question 10

Which of the following statements is true about calmodulin

a) It is a protein which binds calcium ions and activates protein

kinases.

b) It is a protein which binds calcium ions and binds to DNA to

activate transcription.

c) It is a protein which transports calcium ions across the cell

membrane.

d) It is a protein which modifies calcium ion concentration within the

cell.

#Small G-proteins

#They inhibit aden

Chapter 05Results

You have answered 6 out of 10 questions correctly.

Your percentage score is 60%.

Question 1

Which of the following reactions is catalyzed by the enzyme adenylate cyclase?

Your answer:

a) The conversion of ATP to cyclic AMP.

Feedback:

Option b) is catalyzed by a phosphorylase enzyme and deactivates cyclic AMP. The other two reactions described in options c) and d) do not occur.Page reference: 60

Question 2

What is the product, indicated by the letter C in the following diagram?

Your answer:

b) diacylglycerol

Correct answer:

a) inositol triphosphate

Feedback:

Inositol triphosphate is product C. Diacylglycerol is product D. Inositol diphosphate is not involved at all. Phosphatidylinositol diphosphate is the substrate A.Page reference: 65

Question 3

Which of the following statements is true for diacylglycerol (DG) formed in the following reaction?

You did not answer the question.

Correct answer:

a) It is a hydrophobic molecule.

Feedback:

Diacylglycerol is a hydrophobic molecule that acts as a secondary messenger. It remains in the cell membrane and activates protein kinase C.Page reference: 65

Question 4

Which of the following statements is true for inositol triphosphate (IP3) formed in the reaction below?

Your answer:

c) It deactivates the release of calcium ions.

Correct answer:

b) It moves into the cytoplasm.

Feedback:

Structure C is inositol triphosphate. It is a hydrophilic molecule that acts as a secondary molecule and moves into the cytoplasm to activate the release of calcium ions.Page reference: 65-66

Question 5

Which of the following statements is untrue about G-proteins?

Your answer:

a) G-proteins consist of four protein subunits.

Feedback:

G-Proteins are signal proteins that contain three protein subunits and bind GDP in the resting state. They are activated when they bind to membrane-bound receptors. Page reference: 58-59

Question 6

Which of the following is true when a G-protein interacts with a receptor?

Your answer:

c) The G-protein is split into an α-subunit and a β, γ-dimer

Feedback:

The G-protein contains three protein subunit. When it is activated, the α-subunit splits from the remaining two subunits.Page reference: 58-59

Question 7

Which of the following subunits activates adenylate cyclase?

Your answer:

b) The αs-subunit

Feedback:

The αs-subunit activates adenylate cyclase, whereas the αi-subunit deactivates the enzyme. The αq-subunit activates phospholipase C whereas the αo-subunit activates ion channels for the calcium ion.Page reference: 60

Question 8

Which of the following is untrue with respect to small G-proteins?

Your answer:

d) Small G-proteins are the same as G-proteins, but have a lower molecular weight.

Feedback:

All the statements are true except statement d). Small G-proteins are not smaller versions of G-proteins since the latter are made up of three protein subunits. A small G-protein is a single protein.Page reference: 68-69

Question 9

Which of the following statements best explains the action of lithium salts in treating manic depressive illness?

You did not answer the question.

Correct answer:

d) They inhibit a phosphatase enzyme.

Feedback:

Lithium salts inhibit a phosphatase enzyme involved in the resynthesis of phosphatidylinositol. The other enzymes are part of signal transduction processes.Page reference: 66-67

Question 10

Which of the following statements is true about calmodulin

Your answer:

a) It is a protein which binds calcium ions and activates protein kinases.

Feedback:

Calmodulin binds to released calcium ions within the cell and activates protein kinases. The proteins involved in controlling transcription are known as transcription factors. Calcium ions cross cell membranes through ion channels.Page reference: 65-66

1. Cell signaling means all of the following except:A. intercellular communication.B. export of cellular waste products.C. environmental monitoring.D. response to stimuli.

2. In a signal transduction pathway, what is passed from the upstream member of the pathway to the downstream member?A. ElectronsB. ProtonsC. PhosphatesD. information in the form of alterations in protein conformation

3. Both epinephrine and glucagon bind to G protein-coupled receptors and activate glycogen breakdown. Therefore, epinephrine and glucagon must:A. have very similar structures and bind to the same receptor.B. bind to receptors with different ligand-binding sites but similar functions.C. bind to different receptors and activate different second messengers.D. bind to the same receptors, one being intracellular and the other, extracellular.

4. If you break liver cells by homogenization, separate the broken cell membranes (particulate) from the cytoplasm (soluble), and add epinephrine to the soluble portion, the result will be:A. the production of cAMP.B. binding of the epinephrine to its receptor.C. activation of adenylyl cyclase.D. None of these are correct.

5. Glucagon binds to the glucagon receptor, which interacts with a membrane-bound G protein, whose α subunit releases GDP and binds GTP. The α subunit then dissociates from the G protein and diffuses to a membrane-bound adenylyl cyclase which produces cAMP. In this scenario, name the (1) transducer, (2) effector, (3) first messenger, and (4) second messengerA. (1) glucagon (2) cAMP (3) G protein (4) GTPB. (1) G protein (2) adenylyl cyclase (3) glucagon (4) cAMPC. (1) G protein (2) GTP (3) glucagon (4) cAMPD. (1) glucagon (2) G protein (3) adenylyl cyclase (4) cAMP

6. Epinephrine binds to the same type of receptors in liver, fat, and smooth muscle cells. Yet in liver, glycogen breaks down; in fat, triacylglycerols break down; and smooth muscle cells relax. How can the same hormone produce three such different responses?A. The same receptors activate three different second messengers.B. The same second messengers activate three different intracellular cascades.C. The same enzyme that breaks down glycogen also breaks down fat and relaxes muscle.D. None of these are correct.

7. G proteins are said to be self-inactivating. What G-protein function accounts for this?A. GTPase activity of the α subunitB. activation of the effectorC. binding to the receptorD. dissociation of the subunits

8. People who suffer from thyroid adenomas have constitutively activated G proteins in some cells of the thyroid gland. Tumor cells not only secrete copious quantities of thyroid hormones but also divide and grow excessively. Based on these observations, in what kind(s) of signal transduction pathways do the mutant G proteins participate?A. cAMP-regulated pathwaysB. MAP kinase pathwaysC. both cAMP and MAP kinase pathwaysD. neither cAMP nor MAP kinase pathways

9. What factors are responsible for the specificity of G protein-coupled responses?A. Protein kinases can phosphorylate different proteins in different cells.B. Receptors can exist as isoforms.C. G-protein subunits can exist as isoforms.D. All of these are correct.

10. IgE-antigen complex on a mast cell is to phospholipase C as epinephrine on a liver cell is to ________.A. protein kinase CB. cAMPC. adenylyl cyclaseD. GTP

11. Serine and threonine are to _________ as tyrosine is to receptor tyrosine kinases.A. PhosphatasesB. G proteinsC. cAMPD. protein kinases A and C

12. Ryanodine and IP3 receptors are found on ? membranes, whereas epinephrine and glucagon receptors are found on ? membranes.A. plasma, intracellularB. intracellular, plasmaC. mitochondrial, endoplasmic reticulumD. outer, inner

13. Depending on the cell, increases in intracellular Ca2+ can do all of the following except:A. stimulate the increase of intracellular calcium.B. stimulate the removal of intracellular calcium.C. stimulate stimulates the opening of ryanodine receptors.D. stimulate the deactivation of calmodulin.

14. The sequence of events that occurs after insulin binds to its receptor tyrosine kinase is:A. binding of IRS —> phosphorylation of proteins with SH2 domains —> effect

B. binding of proteins with SH2 domains —> phosphorylation of IRS —> effectC. autophosphorylation and phosphorylation of IRS —> binding of proteins with SH2 domains —> effectD. autophosphorylation and binding of IRS —> phosphorylation of proteins with SH2 domains —> effect

15. Proteins with SH2 domains are to ? as adenylyl cyclase and phospholipase C are to G protein-coupled receptors.A. IRSsB. receptor tyrosine kinasesC. insulinD. autophosphorylation

16. Which mutant form of ras is likely to cause malignancy?A. ras that cannot hydrolyze GTPB. ras that cannot bind to GTPC. ras that cannot bind to Grb2 or SosD. ras that cannot bind to Raf

17. in the MAP kinase cascade phosphorylations occur sequentially on:A. receptor-protein tyrosine kinase, Ras-GDP, Soluble Raf, ERKB. receptor-protein tyrosine kinase, Ras-GDP, Soluble Raf, MEKC. receptor-protein tyrosine kinase, Soluble Raf, MEK, ERKD. Ras-GDP, Soluble Raf, TF, MEK

18. What second messenger has been implicated in blood pressure regulation?A. cAMPB. NOC. COD. IP3

19. A mutation in the FAK gene would likely result in:A. abnormal cell shape.B. abnormal wound healing.C. abnormal cell growth.D. All of these are correct.

20. A cell responds to an external stimulus by releasing abscisic acid, increasing cytoplasmic Ca2+ and triggering a net outflow of K+ ions, causing a decrease in turgor pressure. What kind of cell does this describe?A. BacterialB. ViralC. PlantD. Animal

Your Results for: "Self-Study Quiz" Print this page

Site Title: The Physiology Place for Animal Physiology

Book Title: Principles of Animal Physiology, 1e

Book Author:

Moyes

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Chapter 4 > Self-Study Quiz

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September 14, 2011 at 3:05 PM (UTC/GMT)

Summary of Results

40% Correct of 20 Scored items:

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12 Incorrect: 60%

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1. ___________are specialized protein complexes that create an aqueous pore between the cytoplasms of two adjacent cells.

Your Answer:Ion channels

Correct Answer:

Gap junctions

  Sorry, that's incorrect. Ion channels are membrane proteins that form pores through which only specific ions may pass. Please refer to p.85 and p.107 for more information.

2. How do most hydrophobic chemical messengers get transported to a target cell?

Your Answer:They dissolve easily in the circulatory fluids.

Correct Answer:

They bind to carrier proteins in the blood.

  Sorry, that's incorrect. Hydrophobic chemical messengers do not dissolve easily in aqueous solutions (e.g., blood). Please refer to p.109 for more information.

3. When a chemical messenger (or ligand) reaches a target cell, it binds to a receptor. A hydrophobic ligand binds to a(n)________, whereas a hydrophilic ligand binds to a(n) ___________.

Your Answer:transmembrane receptor; intracellular receptor

Correct Answer:

intracellular receptor; transmembrane receptor

  Sorry, that's incorrect. The terms are correct, but they are misplaced in the sentence. Please refer to p.110 for more information.

4. The strength of binding between a ligand and a receptor is usually expressed as the

Your Answer:

affinity constant (Ka).

  You are correct.

5. A transcription factor is a receptor with three domains: a ligand-binding domain, a DNA-binding domain, and a transactivation domain. What kind of receptor is a

transcription factor?

Your Answer:

(blank)

6. How does a ligand-gated ion channel work?

Your Answer:

When a ligand binds to an ion channel, the channel changes conformation and the ion channel opens, allowing ions to cross the membrane.

  You are correct.

7. Which of the following statements about receptor-enzymes is false?

Your Answer:

Receptor-enzymes interact with an intracellular protein called a "G-protein".

  You are correct.

8. _____________ rely on ___________, such as Ca2+, cyclic GMP, phosphatidylinositol, and cyclic AMP, to activate (or inactivate) a variety of pathways within the cell.

Your Answer:G-protein-coupled receptors; G-proteins

Correct Answer:

G-protein-coupled receptors; second messengers

  Sorry, that's incorrect. Please refer to pp.119-120 for more information.

9. Which of the following statements about G-protein signaling pathways is false?

Your Answer:

Receptor serine/threonine kinases directly activate G-proteins, which in turn activate second messengers.

  You are correct.

10.

The autocrine/paracrine signaling system has a ____________signaling distance and ___________duration of response.

Your Answer:

short; short

  You are correct.

11.

Communication among neurons and between neurons and other target cells occurs across short distances at a structure called the __________, a region where the signaling cell and the target cell are very close together.

Your Answer:

synapse

  You are correct.

12.

Which of the following is not a chemical class of hormones?

Your Answer:amines

Correct Answer:

MAP kinases

  Sorry, that's incorrect. This is a chemical class of hormones. Please refer to p.127 for more information.

13.

Because steroids generally act by _______________, their effects are typically _______________ than the effects of peptide hormones.

Your Answer:opening ion channels; faster

Correct Answer:

regulating transcription; slower

  Sorry, that's incorrect. Please refer to p.129 for more information.

14.

Norepinephrine, acetylcholine, and serotonin are what kind of hormones?

Your Answer:steroids

Correct Answer:

amines

  Sorry, that's incorrect. Please refer to p.129 for more information.

15.

Animals use _____________ cell-to-cell communication to send signals between individuals.

Your Answer:paracrine

Correct Answer:

exocrine

  Sorry, that's incorrect. This is a method of cell-to-cell communication within an individual. Please refer to p.125 and p.131 for more information.

16.

_____________ are chemicals released by one animal that cause reactions in another animal of the same species.

Your Answer:Mineralocorticoids

Correct Answer:

Pheromones

  Sorry, that's incorrect. Mineralocorticoids are a class of steroid hormones. Please refer to p.128 and p.132 for more information.

17.

In a ______________, a sense organ senses the stimulus and sends a signal to the integrating center (e.g., the brain), which sends out a signal via a neuron to an endocrine gland. The endocrine gland releases a hormone into the circulatory system, which carries the hormone to the target organs

(e.g., heart, lungs, and muscles).

Your Answer:

second-order feedback loop

  You are correct.

18.

Scientists hypothesize that cell signaling in animals evolved from

Your Answer:

ancestral mechanisms that unicellular organisms use to sense their environment.

  You are correct.

19.

Which of the following statements related to the evolution of cell signaling is false?

Your Answer:Cell signaling pathways in plants and animals share many common features, but they are also distinctly different from each other.

Correct Answer:

Scientists believe that pheromones evolved only recently, as there is no evidence that they exist in unicellular organisms.

  Sorry, that's incorrect. This statement is true. Please refer to pp.139-141 for more information.

20.

What is ecdysone?

Your Answer:A steroid hormone found only in vertebrates.

Correct Answer:

A steroid hormone found only in invertebrates.

  Sorry, that's incorrect. Please refer to p.143 for more information

Multiple Choice Quiz(See related pages)

Results ReporterOut of 25 questions, you answered 11 correctly, for a final grade of 44%.

11 correct (44%)

14 incorrect (56%)

0 unanswered (0%)

Your Results:The correct answer for each question is indicated by a .

1 CORRECT The fundamental units of life are

A)genes.

B)alleles.

C)chromosomes.

D)cells.

Feedback: Correct!

2 CORRECTOrganelles called ____ provide energy from the products of digestion.

A)endoplasmic reticulum

B)mitochondria

C)lysosomes

D)Golgi bodies

Feedback: Correct!

3 INCORRECTTay-Sachs disease results from the absence of a particular enzyme found in the

A)endoplasmic reticulum.

B)mitochondria.

C)lysosomes.

D)Golgi bodies.

Feedback: Incorrect: Please review section 2.1 in your textbook and try again!

4 CORRECTA replicated chromosome consists of two very long strands of identical chromosomal material called

A)telomeres.

B)chromatids.

C)centromeres

.

D)genes.

Feedback: Correct!

5 CORRECT DNA synthesis occurs during the ____ phase of the cell cycle.

A)gap 1 (G1)

B)gap 2 (G2)

C)S

D)Mitosis

Feedback: Correct!

6 CORRECTIn ____, chromosomes align down the center of the cell, held by the spindle.

A)prophase

B)metaphase

C)anaphase

D)telophase

Feedback: Correct!

7 INCORRECTDuring ____, replicated chromosomes condense, the spindle forms, and the nuclear membrane breaks down.

A)prophase

B)metaphase

C)anaphase

D)telophase

Feedback: Incorrect: Please review section 2.2 in your

textbook and try again!

8 CORRECTIn ____, centromeres part and one set of chromosomes is pulled to each end of the cell.

A)prophase

B)metaphase

C)anaphase

D)telophase

Feedback: Correct!

9 CORRECTChromosome tips, or ____, function as a cellular clock that ticks down as pieces are lost from the very ends.

A)chromatids

B)centromeres

C)centrioles

D)telomeres

Feedback: Correct!

10 INCORRECT ____ molecules assist cell movement.

A)Signal transduction

B)Prion

C)Cellular adhesion

D)Peroxisome

Feedback: Incorrect: Please review section 2.3 in your textbook and try again!

11 INCORRECT Which of the following pairs a genetic disorder with the

incorrect defective macromolecule or essential nutrient?

A)Lesch-Nyhan syndrome - nucleic acids

B)maple syrup urine disease - vitamins

C)familial hypercholesterolemia - lipids

D) lactose intolerance - carbohydrate

Feedback: Incorrect: Please review section 2.1 in your textbook and try again!

12 CORRECT Which inherited disease is caused by faulty ion channels?

A)cystic fibrosis

B)Lesch-Nyhan syndrome

C)sickle cell anemia

D)maple syrup urine

disease

Feedback: Correct!

13 INCORRECT Prions are

A)recently discovered organelles in bacteria.

B)a single or double strand of nucleic acid wrapped in a protein coat.

C)a naturally occurring glycoprotein that takes two forms.

D)none of the above.

Feedback: Incorrect: Please review section 2.5 in your textbook and try again!

14 INCORRECT

A child is taken to the doctor with the following symptoms: low blood sugar, darkened skin, muscle weakness, and heartbeat irregularities. The doctor concludes that the child has ALD and the symptoms arise from the accumulation of very-long-chain fatty acids in the cells of the brain and spinal cord. The malfunctioning enzyme is associated with the

A)nucleus.

B)mitochondria.

C)lysosomes.

D)peroxisomes.

Feedback: Incorrect: Please review section 2.1 in your textbook and try again!

15 INCORRECTAssume that a cell has 50 units of DNA at G1 of interphase. How many units of DNA would a cell at prophase of mitosis contain?

A)25

B)50

C)100

D)cannot be determined

Feedback: Incorrect: Please review section 2.2 in your textbook and try again!

16 INCORRECTAssume that a cell has 50 units of DNA at G1 of interphase. How many units of DNA would a cell at telophase of mitosis contain?

A)25

B)50

C)100

D)cannot be determined

Feedback: Incorrect: Please review section 2.2 in your textbook and try again!

17 INCORRECTWhich of the three recognized domains of life were previously considered together as prokaryotes?

A)Archaea and Bacteria

B)Eukarya and Bacteria

C)Eukarya and Archaea

D)prokaryotes are still separately recognized

Feedback: Incorrect: Please review section 2.1 in your textbook and try again!

18 CORRECT

In the inherited condition glycogen cardiomyopathy, teens develop muscle weakness including the heart muscle. The muscle tissue contains huge ____ swollen with the carbohydrate glycogen.

A) lysosomes

B)mitochondria

C)peroxisomes

D)nuclei

Feedback: Correct!

19 INCORRECT

Ann has inherited Sly disease, which is characterized by mental retardation, heart defects, and death. Individuals with this disease lack an enzyme that normally breaks down glycolipid molecules called mucopolysaccharides. Two organelles cause this illness. They are the lysosomes and the

A)nucleus.

B)mitochondria.

C)peroxisomes.

D)ER.

Feedback: Incorrect: Please review section 2.1 in your textbook and try again!

20 CORRECT Secretion involves information transfer from the DNA to

A)mRNA which directs manufacture of proteins.

B)tRNA which directs manufacture of proteins.

C)tRNA which directs manufacture of mRNA.

D)mRNA which directs manufacture of tRNA.

Feedback: Correct!

21 INCORRECT Membrane proteins can be involved

A) in signal transduction.

B)as cellular adhesion molecules.

C)in cell identification.

D)all of the above.

Feedback: Incorrect: Please review section 2.3 in your textbook and try again!

22 CORRECT Cancer can result from

A)deficient cell division.

B)excessive apoptosis.

C)both a and b.

D)neither a nor b.

Feedback: Correct!

23 INCORRECT Which factors do not influence cell division?

A)crowding

B)growth hormones

C)cyclins

D)all of the above influence cell division

Feedback: Incorrect: Please review section 2.2 in your

textbook and try again!

24 INCORRECT____ retain the ability to specialize in particular ways in response to signals.

A)Organelles

B)Eukaryotic cells

C)Cell membranes

D)Stem cells

Feedback: Incorrect: Please review section 2.4 in your textbook and try again!

25 INCORRECTThe cells of which of the three domains of life contain ribosomes?

A)Archaea

B)Bacteria

C)Eukarya

D)all of the above

Feedback: Incorrect: Please review section 2.1 in your textbook and try again!