Essential Biochemistry 3rd Edition by Charlotte W. Pratt - Kathleen Cornely - test bank

Essential Biochemistry 3rd Edition by Charlotte W. Pratt – Kathleen Cornely – test bank

 

Instant Download – Complete Test Bank With Answers

 

 

Sample Questions Are Posted Below

 

Package Title: Pratt & Cornely Test Bank

Course Title: Pratt & Cornely

Chapter Number: 5

 

 

Question type: Multiple Choice

 

 

1) Heme is considered a _____.

 

1. A) catalyst
2. B) prosthetic group
3. C) coenzyme
4. D) cofactor
5. E) none of the above

 

Answer:  B

 

Difficulty:  Easy

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

2) The central ion of the heme group of hemoglobin is _____.

 

1. A) Cu⁺
2. B) Cu²⁺
3. C) Fe²⁺
4. D) Fe³⁺
5. E) none of the above

 

Answer:  C

 

Difficulty:  Easy

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

3) When oxygen is bound to the heme group of myoglobin, it is coordinated between _____ and _____.

 

1. A) F8 His; Fe³⁺ of heme
2. B) E7 His; Fe³⁺ of heme
3. C) F8 His; Fe²⁺ of heme
4. D) E7 His; Fe²⁺ of heme
5. E) none of the above

 

Answer:  D

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

4) Myoglobin is _____;  hemoglobin is _____.

 

1. A) monomeric; dimeric
2. B) monomeric; trimeric
3. C) monomeric; tetrameric
4. D) dimeric; trimeric
5. E) dimeric; tetrameric

 

Answer:  E

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

5) The individual hemoglobin subunits and myoglobin share similar _____ structure but have rather different _____ structure.

 

1. A) primary; secondary
2. B) secondary; tertiary
3. C) primary; tertiary
4. D) secondary and tertiary; primary
5. E) primary and secondary; tertiary

 

Answer:  D

 

Difficulty:  Hard

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

6) What is the prominent type of secondary structure observed in myoglobin?

 

1. A) b-helices
2. B) a-bends
3. C) parallel b-sheets
4. D) antiparallel b-sheets
5. E) a-helices

 

Answer:  E

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

7) Which of the following is an example of a conservative amino acid substitution?

 

1. A) Ile ® Leu
2. B) Ser ® Glu
3. C) Phe ® Tyr
4. D) Asp ® Gln
5. E) Arg ® Cys

 

Answer:  A

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

8) While the composition of hemoglobin in adult humans is a₂b₂, in the developing fetus, _____ is observed

 

1. A) z₂e₂
2. B) a₂z₂
3. C) a₂e₂
4. D) a₂d₂
5. E) a₂g₂

 

Answer:  E

 

Difficulty:  Hard

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

9) The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called _____.

 

1. A) homologous binding
2. B) cooperativity
3. C) fractional saturation
4. D) allosterism
5. E) none of the above

 

Answer:  B

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

10) With respect to oxygen saturation, hemoglobin is _____ saturated at the pO₂ of the lungs and _____ saturated  at the pO₂ of the tissue

 

1. A) 20%; 20%
2. B) 25%; 20%
3. C) 50%; 20%
4. D) 50%; between 30 and 70%
5. E) >90%; between 30 and 70%

 

Answer:  E

 

Difficulty:  Hard

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

11) Which of the following best explains the ability for carbon monoxide (CO) to bind to hemoglobin (Hb) despite the relatively low concentrations of CO?

 

1. A) CO binds to Hb with less affinity than oxygen
2. B) CO binds to Hb with an affinity about the same as oxygen
3. C) CO binds to Hb about 5 times more strongly than oxygen
4. D) CO binds to Hb about 250 times more strongly than oxygen
5. E) none of the above

 

Answer:  D

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

12) Which of the following occurs in hemoglobin upon oxygen binding?

 

1. A) the heme Fe²⁺ is pulled out of the plane of the heme group
2. B) the His coordinated to the heme Fe²⁺ is pushed away from the heme group
3. C) the central cavity between the four subunits is decreased in size
4. D) hemoglobin changes from the R state to the T state
5. E) all of the above occur

 

Answer:  C

 

Difficulty:  Hard

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

13) Which of the following explains the conversion of hemoglobin subunits from deoxy to oxy state?

 

1. A) all four subunits switch simultaneously
2. B) each subunit switches only upon oxygen binding to the particular subunit
3. C) both a subunits simultaneously switch first followed by both b subunits
4. D) both b subunits simultaneously switch first followed by both a subunits
5. E) none of the above

 

Answer:  A

 

Difficulty:  Hard

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

14) Proteins such as hemoglobin are known as _____ proteins since binding of a molecule to one site alter binding to other sites.

 

1. A) ligand-activated
2. B) allosteric
3. C) induced-fit
4. D) cooperative
5. E) none of the above

 

Answer:  B

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

15) A plot of the binding of oxygen to myoglobin as a function of pO2 gives a _____ shape;  a similar plot for hemoglobin gives a _____ shape.

 

1. A) sigmoidal; sigmoidal
2. B) sigmoidal; hyperbolic
3. C) hyperbolic; sigmoidal
4. D) hyperbolic; hyperbolic
5. E) hyperbolic; exponential

 

Answer:  C

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

16) Hemoglobin S, the variant responsible for the misshapen red blood cells characteristic of the disease sickle-cell anemia, is potentially advantageous to heterozygotes because it confers some level of resistance to the disease _____.

 

1. A) AIDS
2. B) malaria
3. C) polycythemia
4. D) rickets
5. E) cyanosis

 

Answer:  B

 

Difficulty:  Easy

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

17) How does CO₂ affect hemoglobin-oxygen binding?

 

1. A) CO₂ binds directly to the oxygen binding site, displacing oxygen and thus promoting the deoxy state
2. B) CO₂ displaces BPG, thus promoting the oxy state
3. C) CO₂ is converted to bicarbonate and H⁺ which promotes the oxy state
4. D) CO₂ is converted to bicarbonate and H⁺ which promotes the deoxy state
5. E) none of the above

 

Answer:  D

 

Difficulty:  Hard

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

18) Which allosteric effector has the greatest ability to stabilize the deoxy state of hemoglobin?

 

1. A) BPG
2. B) CO₂
3. C) O₂
4. D) H⁺
5. E) all of the above have equal ability

 

Answer:  A

 

Difficulty:  Medium

Section Reference:  5-1

Learning Objective:  Compare the structures, oxygen-binding activity, and biological functions of myoglobin and hemoglobin

 

 

19) Which of the following fibers is correctly paired with the protein that forms the fiber?

 

1. A) microfilaments: actin
2. B) microtubule: tubulin
3. C) extracellular support fibers: collagen
4. D) intermediate filaments: keratin
5. E) all of the above

 

Answer:  E

 

Difficulty:  Medium

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

20) During the formation of microfilaments, which of the following occurs?

 

1. A) ATP binds to F-actin
2. B) F-actin polymerizes, becoming G-actin
3. C) ATP hydrolysis is catalyzed by F-actin
4. D) polymerization proceeds quickly at first, then slows after about ten actin monomers have polymerized
5. E) none of the above

 

Answer:  C

 

Difficulty:  Medium

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

21) When a cell moves along a surface, actin _____ occurs at the leading edge while _____ occurs at the trailing edge

 

1. A) polymerization; depolymerization
2. B) depolymerization; polymerization
3. C) denaturation; renaturation
4. D) renaturation; denaturation
5. E) none of the above

 

Answer:  A

 

Difficulty:  Medium

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

22) Which of the following details the nucleotide-binding site when tubulin dimers assemble into microtubules?

 

1. A) both a and b sites are bound to GTP
2. B) the a site is bound to GTP; the b site is bound to GDP
3. C) the a site is bound to GDP; the b site is bound to GTP
4. D) both a and b sites are bound to GDP
5. E) the a site is bound to GTP; the b site is unoccupied following GTP hydrolysis and release of GDP

 

Answer:  B

 

Difficulty:  Hard

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

23) Which of the following explains how cell division is blocked by drugs that prevent proper microtubule function?

 

1. A) the condensation of chromatin requires a microtubule skeleton
2. B) production of new membranes for organelles and nucleus requires microtubules
3. C) chromosomes separate along a microtubule spindle
4. D) division of organelles between daughter cells requires organelle movement along microtubules
5. E) none of the above

 

Answer:  C

 

Difficulty:  Medium

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

24) What is the most prevalent secondary structure observed in the proteins of intermediate filaments?

 

1. A) a-helices
2. B) b-helices
3. C) a-sheets
4. D) b-sheets
5. E) both a-helices and b-helices are observed

 

Answer:  A

 

Difficulty:  Easy

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

25) Which amino acid is critical for crosslinking of keratin fibers?

 

1. A) Ser
2. B) Lys
3. C) His
4. D) Cys
5. E) Gln

 

Answer:  D

 

Difficulty:  Easy

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

26) During the initial synthesis of collagen molecules, _____ and _____ are most often incorporated into the growing protein.

 

1. A) Ser; Gly
2. B) Pro; Ala
3. C) Gly; Pro
4. D) Ala; Gly
5. E) Ser; Pro

 

Answer:  C

 

Difficulty:  Easy

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

27) Ascorbic acid is required for the production of _____ in collagen.

 

1. A) hydroxylysine
2. B) g-carboxyglutamic acid
3. C) desmosine
4. D) aspartate b-semialdehyde
5. E) hydroxyproline

 

Answer:  E

 

Difficulty:  Easy

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

28) The helical structure of collagen contains _____.

 

1. A) three right-handed helices wound around each other in a right-handed triple helix
2. B) three right-handed helices wound around each other in a left-handed triple helix
3. C) three left-handed helices wound around each other in a left-handed triple helix
4. D) three left-handed helices wound around each other in a right-handed triple helix
5. E) none of the above

 

Answer:  D

 

Difficulty:  Medium

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

29) Which amino acid is critical for crosslinking of collagen trimers?

 

1. A) Ser
2. B) Lys
3. C) His
4. D) Cys
5. E) Gln

 

Answer:  B

 

Difficulty:  Easy

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

30) Bone and tendons contain _____ while hair and nails contain _____.

 

1. A) collagen; keratin
2. B) actin; keratin
3. C) tubulin; collagen
4. D) collagen; actin
5. E) tubulin; keratin

 

Answer:  A

 

Difficulty:  Easy

Section Reference:  5-2

Learning Objective:  Relate the structures of fibrous proteins to their functions

 

 

31) In a muscle cell, what is the name for the bundles of myosin tails?

 

1. A) cytoskeleton
2. B) thick filaments
3. C) intermediate filaments
4. D) thin filaments
5. E) none of the above

 

Answer:  B

 

Difficulty:  Easy

Section Reference:  5-3

Learning Objective:  Describe how motor proteins operate

 

 

32) Each myosin head contains a binding site for _____ and a binding site for _____.

 

1. A) tubulin; GTP
2. B) another myosin molecule; ATP
3. C) kinesin; GTP
4. D) actin; ATP
5. E) none of the above

 

Answer:  D

 

Difficulty:  Medium

Section Reference:  5-3

Learning Objective:  Describe how motor proteins operate

 

 

33) Which of the following correctly describes the sequence of events in the myosin-actin cycle?

 

1. A) myosin release from actin, ATP binds to myosin, myosin binds to another actin subunit, release of P_i and ADP, stretched myosin returns to original conformation
2. B) myosin release from actin, ATP binds to myosin, myosin binds to another actin subunit, stretched myosin returns to original conformation, release of P_i and ADP
3. C) ATP binds to myosin, myosin release from actin, myosin binds to another actin subunit, release of P_i and ADP, stretched myosin returns to original conformation
4. D) ATP binds to myosin, myosin release from actin, myosin binds to another actin subunit, stretched myosin returns to original conformation, release of P_i and ADP
5. E) myosin release from actin, myosin binds to another actin subunit, ATP binds to myosin, stretched myosin returns to original conformation, release of P_i and ADP

 

Answer:  C

 

Difficulty:  Hard

Section Reference:  5-3

Learning Objective:  Describe how motor proteins operate

 

 

34) Each kinesin head contains a binding site for _____ and a binding site for _____.

 

1. A) tubulin; GTP
2. B) another kinesin molecule; GTP
3. C) myosin; ATP
4. D) actin; ATP
5. E) tubulin; ATP

 

Answer:  E

 

Difficulty:  Medium

Section Reference:  5-3

Learning Objective:  Describe how motor proteins operate

 

 

35) The heads of kinesin bind to _____;  the light chains of kinesin bind to _____.

 

1. A) tubulin; proteins in the membrane of a vesicle
2. B) proteins in the membrane of an organelle; tubulin
3. C) proteins in the membrane of a vesicle; actin
4. D) collagen fibers; proteins in the cell membrane
5. E) none of the above

 

Answer:  A

 

Difficulty:  Medium

Section Reference:  5-3

Learning Objective:  Describe how motor proteins operate

 

 

36) Which of the following correctly describes the sequence of events in the kinesin reaction cycle?  For simplicity, the two heads are referred to as head 1 and head 2.  Head 1 starts as the leading head.

 

1. A) head 1 releases tubulin, ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ADP release from head 2, ATP hydrolysis in head 1
2. B) ATP binds to head 1, head 2 swings forward, ADP release from head 2, ATP hydrolysis in head 1, head 2 binds to tubulin, head 1 releases tubulin
3. C) ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ATP hydrolysis in head 1, ADP release from head 2, head 1 releases tubulin
4. D) ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ADP release from head 2, ATP hydrolysis in head 1, head 1 releases tubulin
5. E) none of the above

 

Answer:  D

 

Difficulty:  Hard

Section Reference:  5-3

Learning Objective:  Describe how motor proteins operate

 

 

37) Which of the following represents the longest distance traveled by a kinesin-vesicle complex?

 

1. A) movement of a mitochondria in a cardiac cell
2. B) movement of a neurotransmitter vesicle down the axon of a nerve cell
3. C) movement of a glucose filled vesicle to the membrane of a liver cell
4. D) movement of a lipid-filled vesicle within an intestinal cell
5. E) none of the above

 

Answer:  B

 

Difficulty:  Medium

Section Reference:  5-3

Learning Objective:  Describe how motor proteins operate