Question 1

Matching

-The absence of 2,3-BPG causes hemoglobin's affinity for oxygen to______.

Accepted Answer

A)   positively cooperative
B)   cyanosis
C)   His E7
D)   decrease
E)   RF)  hydrogen bondsG)  increaseH)  symmetryI)  His F8J)  ion pairsK)  TL)  hemolytic anemiaM)  sequencial G

Question 2

Muscle contraction is triggered

Accepted Answer

A)  in response to an increase in the cytoplasmic Ca2+ concentration.
B)  in response to a decrease in the cytoplasmic Ca2+ concentration.
C)  in response to an increase in the cytoplasmic cAMP concentration.
D)  in response to a decrease in the cytoplasmic cAMP concentration.
E)  in response to an increase in the cytoplasmic titin concentration. A

Question 3

______of the world's human population carries an inherited variant hemoglobin gene.

Accepted Answer

A)  5%
B)  25%
C)  50%
D)  75%
E)  90% C

Question 4

Which statement about myosin is not true?

Accepted Answer

A)  Myosin is a heterohexamer.
B)  Myosin contains two globular heads.
C)  Myosin contains six different polypeptides
D)  Myosin aggregates to form thick filaments
E)  All of the answers above are true of myosin.

Question 5

The rearrangement of T state hemoglobin to the R state

Accepted Answer

A)  occurs in each protein subunit independently when its heme binds oxygen.
B)  requires the binding of at least three oxygen molecules.
C)  increases the ion pairing interactions of the C-terminal amino acids.
D)  involves the movement of the Fe(II) into the heme plane.
E)  opens a central cavity for BPG binding.

Question 6

During the T to R conformational shift,Fe(II)drags the F-helix via a bond to the side chain of ________.

Accepted Answer

A)  Leu F7
B)  Leu F4
C)  His F8
D)  Leu FG3
E)  Val FG5

Question 7

Fab fragments can be generated by

Accepted Answer

A)  reduction of IgG molecules.
B)  oxidation of IgG molecules.
C)  limited digestion of IgG molecules with papain.
D)  combining two light chains.
E)  combining two heavy chains.

Question 8

Which class of antibodies has been implicated in allergic reactions?

Accepted Answer

A)  IgA
B)  IgD
C)  IgE
D)  IgG
E)  IgM

Question 9

Myoglobin's primary physiological role is to facilitate oxygen ________.

Accepted Answer

A)  storage
B)  metabolism
C)  binding
D)  reduction
E)  diffusion

Question 10

The most rapid way that erythrocytes adapt to high altitudes is

Accepted Answer

A)  by producing genetically altered hemoglobins that have higher O2-binding affinities.
B)  by adopting the symmetry model of allosterism.
C)  by increasing the concentration of hemoglobin.
D)  by relying upon the simpler protein myoglobin.
E)  by increasing the intracellular concentration of BPG.

Question 11

The Ig fold can be described as a

Accepted Answer

A)  globular fold composed of  α\alphaα  helices.
B)  a globular fold composed of a four helix bundle.
C)  a globular fold composed of a  β\betaβ  sandwich.
D)  a globular fold composed of  β\betaβ  barrel.
E)  a coiled-coil.

Question 12

Mammals and other animals have a circulatory system because diffusion is to slow to supply the tissues with oxygen in animals that are larger than 2 millimeter.Explain in one sentence why these circulatory systems contain hemoglobin or other oxygen binding proteins?

Accepted Answer

The answer of Mammals and other animals have a circulatory...

Question 13

You have been studying O₂ binding to a hemerythrin-like protein isolated from an exotic marine worm.Your O₂-binding data are shown in the table below. a.Use the data to generate an O₂-binding curve (do not forget to mark the axes). b.Use the curve to estimate the K_d for the interaction. c.Is there any evidence from your data that this hemoglobin-like protein binds O₂ in a cooperative manner (briefly explain your answer)?

Accepted Answer

The answer of You have been studying O₂ binding to...

Question 14

The Hill plot shows that the fourth oxygen binds to hemoglobin with a ______-fold greater affinity than the first.

Accepted Answer

A)  2
B)  5
C)  10
D)  20
E)  100

Question 15

Which statement about actin is not true?

Accepted Answer

A)  There are two actin genes,one for F-actin and one for G-actin.
B)  Monomeric G-actin polymerizes to form F-actin.
C)  Actin filaments are polar (the ends can be distinguished) 
D)  Actin can bind ATP.
E)  Actin is a common protein in nonmuscle cells.

Question 16

Which of the following statements does not apply to the K value in the equation for the oxygen binding curve of myoglobin?

Accepted Answer

A)  It is numerically equal to p50.
B)  It is defined as that oxygen partial pressure at which half of the oxygen binding sites are occupied.
C)  It is a measure of the affinity of myoglobin for oxygen.
D)  If Y > K,then myoglobin is less than 50% saturated with oxygen.
E)  It is the value of pO2 at which Y = 0.5.

Question 17

Matching

-Mutations that favor the oxidation of the heme iron(II)to iron(III)can cause ______.

Accepted Answer

A)   positively cooperative
B)   cyanosis
C)   His E7
D)   decrease
E)   RF)  hydrogen bondsG)  increaseH)  symmetryI)  His F8J)  ion pairsK)  TL)  hemolytic anemiaM)  sequencial

Question 18

The energy needed to drive muscle contraction comes from ATP hydrolysis that is carried out by

Accepted Answer

A)  G-actin.
B)  F-actin.
C)  myosin heads.
D)  myosin tails.
E)  tropomyosin.

Question 19

When the partial pressure of O2 in venous blood is 30 torr,the saturation of myoglobin with O2 is ______ while the saturation of hemoglobin with O2 is ______.

Accepted Answer

A)  0) 55,0.91
B)  0) 91,0.55
C)  2) 8 torr,26 torr
D)  0) 91,0.97
E)  none of the above

Question 20

Myoglobin is an oxygen binding protein in muscle.Describe in one sentence the overall structure of myoglobin.

Accepted Answer

The answer of Myoglobin is an oxygen binding protein in...

Exam 7: Protein Function Part I: Myoglobin and Hemoglobin

Matching -The absence of 2,3-BPG causes hemoglobin's affinity for oxygen to______.