Campbell Biology
12th Edition
ISBN: 9780135188743
Author: Urry
Publisher: PEARSON
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Chapter 2.1, Problem 3CC
Summary Introduction
To evaluate: The effects of iron deficiency in the human body.
Concept introduction:
Iron is a trace element. Although, it is required in small quantity, it is essential for the maintenance of human body. It is a component of hemoglobin protein present in red blood cells (RBCs).
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Students have asked these similar questions
2. (a)
The binding site of 2,3-bisphosphoglycerate (BPG) (red stick figure) in the deoxyhemo-
globin molecule is illustrated below. Note that the two phosphate groups and the carboxylate group of
the BPG molecule confer strong, negative electrostatic character to the molecule.
B₁-subunit
1.
2.
3.
5.
6.
B₁
(b)
Mutant Hemoglobin
Hb Raleigh
Hb Helsinki
The mutant hemoglobins listed below each have a mutant amino acid in the ß-subunit directly in or in
the vicinity of the BPG binding site. Rank the affinity of the following mutant hemoglobins for binding
BPG (red stick figure above).. Explain your reasoning. The notation, for instance, as given for Hb
Raleigh Val(31)Ala means that Val-1, the first amino acid residue of the ß-subunit, has been substituted
by Ala.
Hb Rahere
Hb Rancho Mirage
Hb Little Rock
B₂
Hb Ohio
Mutation
Val (31)Ala
Lys(382) Met
Lys(382)) Thr
His(143)Asp
His(3143)Gln
a-NHẠ
Ala(142)Asp
His 2
His 143
BPG
His 143
Lys 82
His 2
Rank the affinity of the mutant hemoglobins for…
One of the molecules listed below is effective in reducing O2 affinity of human Hb in the absence of BPG: (1) Glucose 6-phosphate (2) Inositol hexaphosphate (3) Maleic acid (4) Lactate (5) Arginine - Interestingly, this molecule plays the role of BPG in bird and turtle hemoglobin.
A) Write the chemical structure of each molecule mentioned above.
(B) Predict what molecule is most effective in preventing O2 binding to Hb. In 20 words or less explain the rationale for your prediction
In an experiment, hemoglobin is dissociated in a buffer and a subunit is isolated to study for its oxygen binding affinity.
(i) What is the shape of the oxygen dissociation curve is expected in the experiment?Explain why.
(ii) Is the Km of the isolated subunit higher or lower than the Km of an intact hemoglobin?
Chapter 2 Solutions
Campbell Biology
Ch. 2.1 - MAKE CONNECTIONS Explain how table salt has...Ch. 2.1 - Is a trace element an essential element? Explain.Ch. 2.1 - Prob. 3CCCh. 2.1 - MAKE CONNECTIONS Explain how natural selection...Ch. 2.2 - Prob. 1CCCh. 2.2 - A nitrogen atom has 7 protons, and the most common...Ch. 2.2 - Prob. 3CCCh. 2.2 - Prob. 4CCCh. 2.3 - Why does the structure H C = C H fail to make...Ch. 2.3 - What holds the atoms together in a crystal of...
Ch. 2.3 - What holds the atoms together in a crystal of...Ch. 2.4 - Prob. 1CCCh. 2.4 - Which type of chemical reaction, if any, occurs...Ch. 2.4 - WHAT IF? Write an equation that uses the products...Ch. 2 - Compare an element and a Compound.Ch. 2 - DRAW IT Draw the electron distribution diagrams...Ch. 2 - In terms of electron sharing between atoms,...Ch. 2 - What would happen to the concentration of products...Ch. 2 - Prob. 1TYUCh. 2 - Prob. 2TYUCh. 2 - The reactivity of an atom arises from (A) the...Ch. 2 - Which Statement is true of all atoms that are...Ch. 2 - Which of the following statements correctly...Ch. 2 - Prob. 6TYUCh. 2 - The atomic number of sulfur is 16. Sulfur combines...Ch. 2 - What coefficients must be placed in the following...Ch. 2 - DRAW IT Draw Lewis dot structures for each...Ch. 2 - EVOLUTION CONNECTION The percentages of naturally...Ch. 2 - SCIENTIFIC INQUIRY Female luna moths (Actias luna)...Ch. 2 - Prob. 12TYUCh. 2 - Prob. 13TYU
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- e 1.0 0.5- 0 6. Answer the questions below about hemoglobin and myoglobin. a. Sketch and label the binding curves of Mb, Hb, and Hb below. pº₂ b. In the scenarios below for Hb, indicate what effect they would have on the binding curve and give a brief explanation? Scenario Decrease in the concentration of carbon dioxide (CO₂) Distal histidine (the histidine that aids in molecular oxygen binding) mutation to phenylalanine High heat and extreme pH changes Predict if the normal binding curve of Hb will shift right (Hbt), left (HbⓇ), completely to Mb, or no longer bind oxygen completely? Brief Explanationarrow_forward3. (a) The (acid) Bohr effect is defined as the up- take of protons by hemoglobin molecules at pH ≤ 6.5 as O2 is dissociated from the protein in solution. Approxi- mately 0.6 mole protons are taken up for each mole of O2 released by normal human hemoglobin. The effect is seen as a "shift to the right" in the O2 dissociation curves with decrease in pH, indicating that the O2 binding affinity of Hb decreases at lower pH. On the right is a diagram compar- ing the pH dependence of the p50 values of Hb Deer Lodge [His(32)Arg] (filled symbols) and of HbA (- - -) in the absence of organic phosphates, i.e., “Stripped”, and in the presence of saturating concentrations of IHP. On the basis of the definition of the Bohr effect given above, explain why the data in the diagram reflect the Bohr effect for the two types of human hemoglobins. log p50 1.5 1.0 0.5 0.0 -0.5 5 6 stripped 7 pH +DPG 8 IHP 9 (b) The Bohr effect is generally decreased in Hb Deer Louge compared to that in HbA. Provide an…arrow_forwardA team of biochemists uses genetic engineering to modify the interface region between hemoglobin subunits. The resulting hemoglobin variants exist in solution primarily as αβ dimers (few, if any, α2β2 tetramers form). Are these variants likely to bind oxygen more weakly or more tightly? Explain your answer.arrow_forward
- Which of the following statements is false concerning the structure of hemoglobin? a. The binding of BPG stabilizes the T-state of Hb b. The R-state of Hb is favored under environments of high concentrations of O2 c. Hemoglobin's affinity for oxygen increases as protons ionize from the N-terminal tails d. Hemoglobin is stabilized in the low affinity state in the presence of high concentration of protons e. Hemoglobin favors the R-state in basic environmentsarrow_forward30. The cooperative binding behavior of hemoglobin for oxygen is best explained by... Group of answer choices The movement of the proximal histidine upon O2 binding causes a structural change at the binding interface between subunits The oxidation of Fe2+ to Fe3+ and formation of the superoxide ion causes distortion of the protoporphyrin ring, altering binding interface between subunits The tetrameric nature of hemoglobin's quaternary structure directly confers cooperative binding activity The movement of the distal histidine upon O2 binding causes a structural change at the binding interface between subunits The binding of O2 causes a pH shift that changes the protonation state of amino acids located at the interface between subunits The solubility of hemoglobin in aqueous solution and its insolubility in nonpolar environmentsarrow_forward2. j The following plots show an oxygen binding curve for hemoglobin under a certain set of conditions. For each plot, sketch (with reasonable accuracy) a second curve showing how the binding of oxygen to hemoglobin would be altered by the change in conditions noted. a. Increase in pCO2 b. Dissociation of native Hb into aß dimers 1 0.8 0.8 0.6 Y 0.4 0.6 Y 0.4 0.2 0.2 po2 pO2arrow_forward
- In one type of hemoglobin mutant the amino acid change generates a strong ionic interaction stabilizing the T state conformation, but only under conditions of lower pH, e.g., at pH 7.2 compared to pH 7.6. Explain what effect this mutation would have on the amount of O2 delivered to the tissue. More O2 delivered to the tissue because the R-T equilibrium would be shifted to the T state in tissues. More O₂ delivered to the tissue because the R-T equilibrium would be shifted to the T state in lungs. Less O2 delivered to the tissue because the R-T equilibrium would be shifted to the T state in lungs. Less O₂ delivered to the tissue because the R-T equilibrium would be shifted to the T state in tissues. More O2 delivered to the tissue because the R-T equilibrium would be shifted to the R state in tissues.arrow_forwardFill in the blanks to describe the sequence of molecular events that follow the binding of oxygen molecule to the first binding site in deoxy hemoglobin and lead to a T to R conformational change. Oxygen binds to one of the Hb subunits causing the coordination bond to move as well. This in turn causes an to move about 0.4A, causing that interacts with it via a which is part of the same alpha helical segment as to move away from a nearby positively charged residue. As a result, this residue and an ion pair that stabilises (intra or inter ?) subunit contacts is broken, inducing the movement of C-terminus of the Hb subunit to which oxygen bound toward the (center / edge?) of the Hb tetramer. This alters the overall fold of Hb monomers from to form and causes 2,3 BPG to Give you answers is a numbered list starting from 1arrow_forwardStudies of oxygen transport in pregnant mammals show that the O2-saturation curves of fetal and maternal blood are markedly different when measured under the same conditions. Fetal erythrocytes contain astructural variant of hemoglobin, HbF, consisting of two α and two γ subunits (α2 γ2 ), whereas maternal erythrocytes contain HbA (α2β2).(a) Which hemoglobin has a higher affinity for oxygen under physiological conditions, HbA or HbF? Explain.(b) What is the physiological significance of the different O2 affinities?(c) When all the BPG is carefully removed from samples of HbA and HbF, the measured O2 -saturation curves (and consequently the O2 affinities) are displaced to the left. However, HbA now has a greater affinity for oxygen than does HbF. When BPG is reintroduced, the O2 -saturation curves return to normal, as shown in the graph. What is the effect of BPG on the O2 affinity of hemoglobin? How can the above information be used to explain the different O2 affinities of fetal and…arrow_forward
- Why does the dissociation constant change for hemoglobin in high and low 02 concentrations? O Hemoglobin is a tetramer and subunits have decreased dissociation of 02 when a neighboring subunit has bound 02 O Hemoglobin is a monomeric protein with increased dissociation of 02 when a neighboring molecule has bound 02 O Hemoglobin is a tetramer and subunits have increased dissociation of 02 when a neighboring subunit has bound CO O Hemoglobin is a tetramer and subunits have increased dissociation of O2 when a neighboring subunit has bound O2arrow_forwardChemistry Red cells have a volume of ~86 fL. If the concentration of hemoglobin in red cells is ~330 g/L and its Mr is 64,500 b) In the generation of a red cell, the synthesis of all the hemoglobin molecules of the cell takes about 40 h. How many hemoglobin molecules are synthesized in one second per red cell? c) How many subunits (monomers) of hemoglobin are produced in one minute?arrow_forwardThe graphs below show 02-binding curves of several proteins including myoglobin (Mb) and hemoglobin (Hb). If curve 3 (-) represents the 02 binding behavior of normal hemoglobin, which curve represents an 02-binding transporter with the same p50 as normal hemoglobin? 1.0- YO, 0.5 0.0 pO,(torr) O A. 1 B. 2 O C. 4 O D. 5 E. Both "2" and "4"arrow_forward
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