The structure of normal adult hemoglobin can be described as tetramer composed o
ID: 179708 • Letter: T
Question
The structure of normal adult hemoglobin can be described as tetramer composed of four myoglobin molecules. a tetramer composed of two alpha beta dimers. a tetramer composed of two alpha 2 and two beta 2 dimers. a tetramer composed of two alpha 2 and two gamma 2 dimers. None of these accurately describe hemoglobin. Which of the following is correct concerning fetal hemoglobin? Fetal hemoglobin is composed of two alpha and two gamma subunits. Fetal hemoglobin binds 2, 3-BPG more tightly than normal adult hemoglobin. Fetal hemoglobin binds oxygen less than HbA at all p O_2. Fetal hemoglobin does not exist in the T-form. None of the above. Hemoglobin-binding of oxygen is best described as a concerted model. Michaelis-Menten model. sequential model. combination of sequential and concerted models. None of the above. What is the Bohr effect? the ability of hemoglobin to retain oxygen when in competition with myoglobin the regulation of hemoglobin-binding by hydrogen ions and carbon dioxide the alteration of hemoglobin conformation during low oxygen stress All of the above. None of the above. Which of the following statements is correct for hemoglobin and oxygen transport? The oxygen binds to the proximal histidine residue of the globin chain. Bonding of carbon dioxide to hemoglobin molecules increases the binding of oxygen. Hemoglobin binds more oxygen as the pH is lowered. Hemoglobin binds more oxygen at higher [BPG] concentrations. The binding of each O_2 molecule to hemoglobin increases its affinity for the next O_2 .Explanation / Answer
33. the structure of normal adult hemoglobin can be described as:
a tetramer composed of two alpha-beta dimers-answer
two alpha and two beta chains
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34 a correct statement concerning fetal hemoglobin:
fetal hemoglobin is composed of two alpha and two gamma subunits------------------answer
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35. Hemoglobin-binding of oxygen is best described as a
A) concerted model.
8) Michaelis-Menten model.
C) sequential model.
D) combination of sequential and concerted models. ------------------answer
E) None of the above.
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36. What is the Bohr effect,
A) the ability of hemoglobin to retain oxygen when in competition with myoglobin
B) the regulation of hemoglobin.binding by hydrogen ions and carbon dioxide -------answer
C) the alteration of hemoglobin conformation during low oxygen stress
0) All of the above.
E)None of the above.
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Explanation
Hemoglobin : it has a quaternary structure normal for some multi-subunit globular proteins. The majority of the amino acids in hemoglobin shape alpha helices, associated by short non-helical sections. Hydrogen bonds balance out the helical segments inside this protein, bringing about attractions inside the particle, collapsing every polypeptide chain into a particular shape. Hemoglobin's quaternary structure originates from its four subunits in approximately a tetrahedral plan.
In many vertebrates, the hemoglobin particle is a gathering of four globular protein subunits. Every subunit is made out of a protein chain firmly connected with a non-protein prosthetic heme gather. Every protein chain orchestrates into an arrangement of alpha-helix basic sections associated together in a globin crease course of action, purported in light of the fact that this plan is a similar collapsing theme utilized as a part of other heme/globin proteins, for example, myoglobin. This collapsing design contains a pocket that unequivocally ties the heme assemble.
A heme gather comprises of an iron (Fe) particle (charged iota) held in a heterocyclic ring, known as a porphyrin. This porphyrin ring comprises of four pyrrole particles consistently connected together (by methine spans) with the iron particle bound in the center.[36] The iron particle, which is the site of oxygen authoritative, arranges with the four nitrogen molecules in the focal point of the ring, which all lie in one plane. The iron is bound firmly (covalently) to the globular protein by means of the N molecules of the imidazole ring of F8 histidine buildup (otherwise called the proximal histidine) beneath the porphyrin ring. A 6th position can reversibly tie oxygen by an arrange covalent bond, finishing the octahedral gathering of six ligands. Oxygen ties in an "end-on bowed" geometry where one oxygen iota ties to Fe and alternate juts at a point. At the point when oxygen is not bound, a feebly reinforced water atom fills the site, shaping a mutilated octahedron.
Oxyhemoglobin: it is framed amid physiological breath when oxygen ties to the heme part of the protein hemoglobin in red platelets. This procedure happens in the aspiratory vessels adjoining the alveoli of the lungs. The oxygen then goes through the circulatory system to be dropped off at cells where it is used as a terminal electron acceptor in the creation of ATP by the procedure of oxidative phosphorylation. It doesn't, be that as it may, neutralize a diminishing in blood pH. Ventilation, or breathing, may turn around this condition by evacuation of carbon dioxide, hence bringing about a move up in pH.
Hemoglobin exists in two structures, a tight (tense) shape (T) and a casual frame (R). Different elements, for example, low pH, high CO2 and high 2,3 BPG at the level of the tissues support the tight shape, which has low oxygen liking and discharges oxygen in the tissues. On the other hand, a high pH, low CO2, or low 2,3 BPG favors the casual shape, which can better tie oxygen. The halfway weight of the framework likewise influences O2 liking where, at high fractional weights of oxygen, (for example, those present in the alveoli), the casual (high fondness, R) state is favored. Contrarily, at low halfway weights, (for example, those present in breathing tissues), the (low proclivity, T) tense state is favored. Furthermore, the authoritative of oxygen to the iron(II) heme maneuvers the iron into the plane of the porphyrin ring, bringing on a slight conformational move. The move urges oxygen to tie to the three residual heme units inside hemoglobin (accordingly, oxygen restricting is helpful)
A heme bunch comprises of an iron (Fe) particle (charged iota) held in a heterocyclic ring, known as a porphyrin. This porphyrin ring comprises of four pyrrole particles consistently connected together (by methine spans) with the iron particle bound in the center.The iron particle, which is the site of oxygen authoritative, facilitates with the four nitrogen molecules in the focal point of the ring, which all lie in one plane. The iron is bound emphatically (covalently) to the globular protein by means of the N molecules of the imidazole ring of F8 histidine buildup (otherwise called the proximal histidine) beneath the porphyrin ring. A 6th position can reversibly tie oxygen by a facilitate covalent bond, finishing the octahedral gathering of six ligands. Oxygen ties in an "end-on bowed" geometry where one oxygen molecule ties to Fe and alternate juts at a point. At the point when oxygen is not bound, a feebly fortified water atom fills the site, framing a twisted octahedron.
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