Question 1

Which of the following occurs when hemoglobin switches from the T (deoxy)state to the R (oxy)state?

Accepted Answer

A) the heme group goes from a slightly puckered conformation to a flat conformation 
B) the ferrous ion is pulled into the plane of the heme group 
C) the F8 (proximal)histidine rotates about 8S1U1P1$\circ$S1S1P0 to better align with the ferrous ion 
D) movement of the F8 histidine causes a shift in the F helix,thus weakening interactions with other subunits 
E) all of the above 
A) the heme group goes from a slightly puckered conformation to a flat conformation 
B) the ferrous ion is pulled into the plane of the heme group 
C) the F8 (proximal)histidine rotates about 8S1U1P1$\circ$S1S1P0 to better align with the ferrous ion 
D) movement of the F8 histidine causes a shift in the F helix,thus weakening interactions with other subunits 
E) all of the above

Question 2

Using the following sequence from the coding strand of DNA,determine the amino acid sequence of the corresponding protein.Make three different mutations: (1)silent, (2)missense with little or no effect upon the protein structure (indicate the amino acid substitution)and (3)nonsense.
CATTTATATGAAAGC

Accepted Answer

His-Leu-Tyr-Glu-Ser

Silent wi

Question 3

The binding of oxygen to hemoglobin is said to be _______________.

Accepted Answer

A) high affinity 
B) low affinity 
C) sigmoidal 
D) cooperative 
E) sequential 
A) high affinity 
B) low affinity 
C) sigmoidal 
D) cooperative 
E) sequential

Question 4

Which of the following is true regarding the effectors of hemoglobin-oxygen binding?

Accepted Answer

A) an increase in blood pH will cause hemoglobin to bind more tightly to oxygen 
B) increased CO2 from increased muscle activity will result in an increase in the R state of hemoglobin 
C) increased Cl- will cause the formation of a salt bridge between two Lys residues,one on an $\alpha$ subunit,the other on a $\beta$ subunit 
D) the binding site of 2,3-BPG contains several Asp and Glu residues which are repelled by the similar charge,pushing the two $\beta$ subunits away from each other 
E) all of the above 
A) an increase in blood pH will cause hemoglobin to bind more tightly to oxygen 
B) increased CO2 from increased muscle activity will result in an increase in the R state of hemoglobin 
C) increased Cl- will cause the formation of a salt bridge between two Lys residues,one on an $\alpha$ subunit,the other on a $\beta$ subunit 
D) the binding site of 2,3-BPG contains several Asp and Glu residues which are repelled by the similar charge,pushing the two $\beta$ subunits away from each other 
E) all of the above

Question 5

2,3-Bisphosphoglycerate is known to interact with hemoglobin in the following ways:
carboxylate with Lys
C-2 phosphate with protonated His
C-3 phosphate with N-terminal amino acid
Using the structure of 2,3-bisphosphoglycerate,show these interactions and identify what type of interaction occurs.

Accepted Answer

All intera

Question 6

Which of the following explains why the ferrous ion is not oxidized to the ferric state in the globin proteins even though free heme in solution is readily oxidized?

Accepted Answer

A) when bound to globins,the heme is always planar;when free in solution,heme adopts a non-planar configuration which allows the oxidation of the iron 
B) the globin proteins provide a hydrophobic environment that prevents oxidation 
C) coordination with the proximal histidine allows any oxidized iron to be rapidly reduced back to the ferrous state 
D) since the oxygen is hydrogen bound to the distal histidine,if oxidation of iron does occur,the distal histidine allows for rapid reduction 
E) none of the above 
A) when bound to globins,the heme is always planar;when free in solution,heme adopts a non-planar configuration which allows the oxidation of the iron 
B) the globin proteins provide a hydrophobic environment that prevents oxidation 
C) coordination with the proximal histidine allows any oxidized iron to be rapidly reduced back to the ferrous state 
D) since the oxygen is hydrogen bound to the distal histidine,if oxidation of iron does occur,the distal histidine allows for rapid reduction 
E) none of the above

Which of the following occurs when hemoglobin switches from the T (deoxy)state to the R (oxy)state?

Using the following sequence from the coding strand of DNA,determine the amino acid sequence of the corresponding protein.Make three different mutations: (1)silent, (2)missense with little or no effect upon the protein structure (indicate the amino acid substitution)and (3)nonsense. CATTTATATGAAAGC

The binding of oxygen to hemoglobin is said to be _______________.

Which of the following is true regarding the effectors of hemoglobin-oxygen binding?

2,3-Bisphosphoglycerate is known to interact with hemoglobin in the following ways: carboxylate with Lys C-2 phosphate with protonated His C-3 phosphate with N-terminal amino acid Using the structure of 2,3-bisphosphoglycerate,show these interactions and identify what type of interaction occurs.

Which of the following explains why the ferrous ion is not oxidized to the ferric state in the globin proteins even though free heme in solution is readily oxidized?

The Scope of Biochemistry

The Matrix of Life: Weak Interactions in an Aqueous Environment

The Energetics of Life

Nucleic Acids

Introduction to Proteins: the Primary Level of Protein Structure

The Three-Dimensional Structure of Proteins

Contractile Proteins and Molecular Motors

Carbohydrates: Sugars,saccharides,glycans

Lipids,membranes and Cellular Transport

Enzymes: Biological Catalysts

Chemical Logic of Metabolism

Carbohydrate Metabolism: Glycolysis, gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Citric Acid Cycle and Glyoxylate Cycle

Electron Transport, oxidative Phosphorylation, and Oxygen Metabolism

Photosynthesis

Lipid Metabolism I: Fatty Acids,triacylglycerols,and Lipoproteins

Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Lipid Metabolism Ii: Membrane Lipids, steroids, isoprenoids, and Eicosanoids

Metabolism of Nitrogenous Compounds I: Principles of Biosynthesis, utilization, and Turnover

Metabolism of Nitogenous Compounds Ii: Amino Acids, porphyrins, and Neurotransmitters

Nucleotide Metabolism

Mechanisms of Signal Transduction

Genes,genomes and Chromosomes

Dna Replication

Dna Restructuring: Repair,recombination,rearrangement,amplification

Information Readout: Transcription and Post-Transcriptional Processing

Information Decoding: Translation and Post-Translational Protein Processing

Regulation of Gene Expression

Filters

Exam 7: Protein Function and Evolution

Which of the following occurs when hemoglobin switches from the T (deoxy)state to the R (oxy)state?

Using the following sequence from the coding strand of DNA,determine the amino acid sequence of the corresponding protein.Make three different mutations: (1)silent, (2)missense with little or no effect upon the protein structure (indicate the amino acid substitution)and (3)nonsense. CATTTATATGAAAGC

The binding of oxygen to hemoglobin is said to be _______________.

Which of the following is true regarding the effectors of hemoglobin-oxygen binding?

2,3-Bisphosphoglycerate is known to interact with hemoglobin in the following ways: carboxylate with Lys C-2 phosphate with protonated His C-3 phosphate with N-terminal amino acid Using the structure of 2,3-bisphosphoglycerate,show these interactions and identify what type of interaction occurs.

Which of the following explains why the ferrous ion is not oxidized to the ferric state in the globin proteins even though free heme in solution is readily oxidized?

The Scope of Biochemistry

The Matrix of Life: Weak Interactions in an Aqueous Environment

The Energetics of Life

Nucleic Acids

Introduction to Proteins: the Primary Level of Protein Structure

The Three-Dimensional Structure of Proteins

Contractile Proteins and Molecular Motors

Carbohydrates: Sugars,saccharides,glycans

Lipids,membranes and Cellular Transport

Enzymes: Biological Catalysts

Chemical Logic of Metabolism

Carbohydrate Metabolism: Glycolysis, gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Citric Acid Cycle and Glyoxylate Cycle

Electron Transport, oxidative Phosphorylation, and Oxygen Metabolism

Photosynthesis

Lipid Metabolism I: Fatty Acids,triacylglycerols,and Lipoproteins

Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Lipid Metabolism Ii: Membrane Lipids, steroids, isoprenoids, and Eicosanoids

Metabolism of Nitrogenous Compounds I: Principles of Biosynthesis, utilization, and Turnover

Metabolism of Nitogenous Compounds Ii: Amino Acids, porphyrins, and Neurotransmitters

Nucleotide Metabolism

Mechanisms of Signal Transduction

Genes,genomes and Chromosomes

Dna Replication

Dna Restructuring: Repair,recombination,rearrangement,amplification

Information Readout: Transcription and Post-Transcriptional Processing

Information Decoding: Translation and Post-Translational Protein Processing

Regulation of Gene Expression

Filters