Question 1

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. 
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 2

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

Oxygen-binding proteins increa

Question 3

Muscle contraction is directly caused by

Accepted Answer

A) structural changes in actin. 
B) structural changes in myosin. 
C) structural changes in the A band. 
D) structural changes in the Z disk. 
E) None of the above is correct. 
A) structural changes in actin. 
B) structural changes in myosin. 
C) structural changes in the A band. 
D) structural changes in the Z disk. 
E) None of the above is correct.

Question 4

The Bohr effect refers to

Accepted Answer

A) the decrease in affinity of Hb for O2 when the pH goes down 
B) the decrease in affinity of Hb for O2 when the pH goes up 
C) the increase in the affinity of Hb for O2 when the O2 concentration goes up 
D) the decrease in affinity of Hb for O2 when the BPG concentration goes up 
E) the decrease in affinity of Hb for O2 when the BPG concentration goes down 
A) the decrease in affinity of Hb for O2 when the pH goes down 
B) the decrease in affinity of Hb for O2 when the pH goes up 
C) the increase in the affinity of Hb for O2 when the O2 concentration goes up 
D) the decrease in affinity of Hb for O2 when the BPG concentration goes up 
E) the decrease in affinity of Hb for O2 when the BPG concentration goes down

Question 5

Hemerythrin and hemocyanin are:

Accepted Answer

A) human mutant hemoglobins with decreased oxygen affinity. 
B) hemoglobin variants that are found in animals at high altitude. 
C) synthetic derivatives of hemoglobin's heme group used in artificial blood substitutes. 
D) oxygen transport proteins found in invertebrates. 
E) tetrameric hemoglobin derivatives containing only $\alpha$-chains ($\alpha$4 tetramers). 
A) human mutant hemoglobins with decreased oxygen affinity. 
B) hemoglobin variants that are found in animals at high altitude. 
C) synthetic derivatives of hemoglobin's heme group used in artificial blood substitutes. 
D) oxygen transport proteins found in invertebrates. 
E) tetrameric hemoglobin derivatives containing only $\alpha$-chains ($\alpha$4 tetramers).

Question 6

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) R
F)hydrogen bonds
G)increase
H)symmetry
I)His F8
J)ion pairs
K)T
L)hemolytic anemia
M)sequencial 
A) positively cooperative 
B) cyanosis 
C) His E7 
D) decrease 
E) R
F)hydrogen bonds
G)increase
H)symmetry
I)His F8
J)ion pairs
K)T
L)hemolytic anemia
M)sequencial

Question 7

Myoglobin's secondary structure is primarily composed of ______________.

Accepted Answer

A) parallel $\beta$-sheets 
B) antiparallel $\beta$-sheets 
C) ($\alpha$-helices) 
D) ($\varOmega$-loops) 
E) polyproline helices 
A) parallel $\beta$-sheets 
B) antiparallel $\beta$-sheets 
C) ($\alpha$-helices) 
D) ($\varOmega$-loops) 
E) polyproline helices

Question 8

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 Kd 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

a.see curve @#IMG-DLM& b.see curve, K_d e

Question 9

The oxygen binding by hemocyanins is mediated by

Accepted Answer

A) an iron ion 
B) a pair of iron ions 
C) a heme group 
D) a copper atom 
E) a pair of copper atoms 
A) an iron ion 
B) a pair of iron ions 
C) a heme group 
D) a copper atom 
E) a pair of copper atoms

Question 10

Hemoglobin is a heterotetramer.How many protomers are present in hemoglobin?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 4 
A) 0 
B) 1 
C) 2 
D) 3 
E) 4

Question 11

If the gene for myoglobin is "knocked out" in mice, the mice:

Accepted Answer

A) have larger lungs. 
B) respire extremely rapidly. 
C) have dark brown muscle tissue. 
D) appear normal, with lighter colored muscle tissue. 
E) have their growth stunted. 
A) have larger lungs. 
B) respire extremely rapidly. 
C) have dark brown muscle tissue. 
D) appear normal, with lighter colored muscle tissue. 
E) have their growth stunted.

Question 12

Consider a hypothetical hemoglobin-like molecule with a Hill coefficient (constant)of 1 and the same p50 value as normal hemoglobin.Choose the statement below that best describes the two proteins.

Accepted Answer

A) There is a cooperative interaction between oxygen-binding sites in both the hypothetical and normal hemoglobins. 
B) The hypothetical hemoglobin has a greater oxygen affinity than normal hemoglobin. 
C) The oxygen binding curve for the hypothetical hemoglobin is hyperbolic, and the curve for normal hemoglobin is sigmoidal. 
D) The two hemoglobins would be able to deliver about the same amount of oxygen to the tissues. 
E) At pO2 less than p50, normal hemoglobin has a greater YO2 value. 
A) There is a cooperative interaction between oxygen-binding sites in both the hypothetical and normal hemoglobins. 
B) The hypothetical hemoglobin has a greater oxygen affinity than normal hemoglobin. 
C) The oxygen binding curve for the hypothetical hemoglobin is hyperbolic, and the curve for normal hemoglobin is sigmoidal. 
D) The two hemoglobins would be able to deliver about the same amount of oxygen to the tissues. 
E) At pO2 less than p50, normal hemoglobin has a greater YO2 value.

Question 13

Which gas does not bind to the porphyrin ring Fe(II)ion in myoglobin?

Accepted Answer

A) NO 
B) CO 
C) CO2 
D) O2 
E) H2S 
A) NO 
B) CO 
C) CO2 
D) O2 
E) H2S

Question 14

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

Accepted Answer

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

Exam 7: Protein Function Part I: Myoglobin and Hemoglobin

Which statement about actin is not true?

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?

Muscle contraction is directly caused by

The Bohr effect refers to

Hemerythrin and hemocyanin are:

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

Myoglobin's secondary structure is primarily composed of ______________.

The oxygen binding by hemocyanins is mediated by

Hemoglobin is a heterotetramer.How many protomers are present in hemoglobin?

If the gene for myoglobin is "knocked out" in mice, the mice:

Consider a hypothetical hemoglobin-like molecule with a Hill coefficient (constant)of 1 and the same p50 value as normal hemoglobin.Choose the statement below that best describes the two proteins.

Which gas does not bind to the porphyrin ring Fe(II)ion in myoglobin?

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

Introduction to the Chemistry of Life

Water

Nucleotides, Nucleic Acids, and Genetic Information

Amino Acids

Proteins: Primary Structure

Proteins: Three-Dimensional Structure

Carbohydrates

Lipids and Biological Membranes

Membrane Transport

Enzyme Catalysis

Enzyme Kinetics, Inhibition and Control

Biochemical Signaling

Introduction to Metabolism

Glycogen Metabolism and Gluconeogenesis

Glucose Catabolism

Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Mammalian Fuel Metabolism: Integration and Regulation

Nucleotide Metabolism

Nucleic Acid Structure

Dna Replication, Repair and Recombination

Transcription and Rna Processing

Translation

Regulation of Gene Expression

Filters

Consider a hypothetical hemoglobin-like molecule with a Hill coefficient (constant)of 1 and the same p₅₀ value as normal hemoglobin.Choose the statement below that best describes the two proteins.