Suppose myoglobin is prepared with Zn²+ in the place of Fe²+ in the porphyrin. Would you expect this modified myoglobinto bind oxygen?No, because Zn²+ cannot partially transfer an electron to oxygen to form a complex.Fe²+ .Yes, because oxygen can form a bond with either Zn²+2+No, because the larger size of Zn²+ will prevent the ion from fitting within the porphyrin ring.Yes, because oxygen binding to myoglobin depends solely on the presence of a distal histidine.or

Heme is a prosthetic group found in proteins like myoglobin. Heme has a protoporphyrin ring that is…

Answered: Suppose myoglobin is prepared with Zn²+…

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter8: Muscle Physiology

Section: Chapter Questions

Problem 2TAHL

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Similar questions

Certain multi-headed myosins bind cooperatively to actin filaments. The binding interaction is mainly electrostatic in nature, so the presence of additional salt (ions) in solution can interfere with binding; ions will tend to associate with charged residues on the two proteins, blocking electrostatic attractions that would otherwise take place. Briefly describe the expected shape of the binding curve for one of these myosins, and what will happen to the shape when the salt concentration increases.
The filaments of skeletal muscle are moved by free energy derived from the hydrolysis of ATP. During sustained muscle contraction ATP levels remain fairly constant, while levels of creatine phosphate fall. Explain why this is so. Under what circumstances is an oxygen debt incurred during muscle contraction?
Explain how the overall three-dimensional shape of myoglobin allows it to function as an oxygen-storage molecule
Myosin II has a duty ratio of 10 percent, and its step size is 8 nm. In contrast, myosin V has a much higher duty ratio (about 70 percent) and takes 36-nm steps as it walks down an actin filament. What differences between myosin II and myosin V account for their different properties?
Myoglobin’s oxygen-binding curve exhibits a shape best described as— serpentine. hyperbolic. straight. sigmoidal. bell.
You know from experience that skeletal muscle tires quite quickly, especially if there is not enough oxygen. Interestingly, shellfish such as clams can maintain a month-long contraction in the muscle that keeps the shell closed. No oxygen gets in this situation. These muscles have a different version of myosin called paramyosin. Knowing what you know about the cellular mechanism of muscle contraction, propose a hypothesis to explain how paramyosin might work.
With regard to muscle contraction, which of the following is an INCORRECT statement with regard to the interactions of filaments that occur in the sarcomere? A. When muscles are relaxed tropomyosin blocks binding sites on actin subunits, which keeps cross-bridges from forming. B. The myosin heads conduct a power stroke motion to slide when bound to actin, to move the "thin" filaments towards the center of the sarcomere. C. During contraction, actin subunits are removed from the ends of the "thin" filaments to shorten actin polymers, thus reducing the length of the sarcomere. D. "Thick" filaments are anchored at the M-line, while "thin" filaments are anchored at the Z-line. E. Numerous myosin heads engage with the actin filaments simultaneously, such that there is no back-slipping during the contraction process.
The sliding-filament model of skeletal-muscle contraction assumes a sliding or slipping of interdigitating filaments of actin and myosin. Electron micrographs show that during contraction the actin and my-osin filaments remain of constant length while the distance between Z lines shortens. Explain how this happens in terms of the molecular structure of the muscle filaments. What is the role of regulatory pro-teins (troponin and tropomyosin) in contraction?
Calmodulin is found in smooth muscle cells and performs a similar function to troponin in striated muscle fibers. However, calmodulin not only gets activated by Ca2+ but also slows the release of Ca2+ from the sarcoplasmic reticulum. How might this difference relate to the different kinds of contractions smooth muscles do in comparison to striated muscles?
Skeletal muscle cells undergo contractions based on a molecular mechanism involving: 1)the sliding of actin and myosin filaments past each other without any change in filament length 2) the shortening of actin filaments following direct interaction with myosin 3) dynamic instability of microtubules 4)none
Explain how the structure of myoglobin changes upon oxygen binding.
Muscle fibers that have a high number of mitochondria, contain largeamounts of myoglobin, and exhibit low rates of ATP hydrolysis arecalled __________ fibers.a. slow-glycolyticb. fast-glycolyticc. intermediated. fast-oxidativee. slow-oxidative

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