CUSTOM BIOLOGY CONCEPTS & CONNECTIONS
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ISBN: 9781323194188
Author: Campbell
Publisher: Pearson Custom Publishing
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Chapter 30, Problem 18TYK
When a person dies, muscles become rigid and fixed in position—a condition known as rigor. Rigor mortis occurs because muscle cells are no longer supplied with ATP (when breathing stops, ATP synthesis ceases). Calcium also flows freely into dying cells. The rigor eventually disappears because the biological molecules break down. Explain, in terms of the mechanism of contraction described in Modules 30.9 and 30.10, why the presence of calcium and the lack of ATP would cause muscles to become rigid, rather than limp, soon after death.
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Chapter 30 Solutions
CUSTOM BIOLOGY CONCEPTS & CONNECTIONS
Ch. 30 - Complete this concept map on animal movement.Ch. 30 - A humans internal organs are protected mainly by...Ch. 30 - Arm muscles and leg muscles are arranged in...Ch. 30 - Gravity would have the least effect on the...Ch. 30 - Prob. 5TYKCh. 30 - Prob. 6TYKCh. 30 - When a dog is running fast, its body position is...Ch. 30 - What is the role of calcium in muscle contraction?...Ch. 30 - Muscle A and muscle B have the same number of...Ch. 30 - Prob. 10TYK
Ch. 30 - Prob. 11TYKCh. 30 - Prob. 12TYKCh. 30 - Prob. 13TYKCh. 30 - Describe how you bend your arm, starting with...Ch. 30 - Prob. 15TYKCh. 30 - Drugs are often used to relax muscles during...Ch. 30 - An earthworms body consists of a number of...Ch. 30 - When a person dies, muscles become rigid and fixed...Ch. 30 - SCIENTIFIC THINKING Imagine you have a friend who...
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- Why do you think a person is able to perform anaerobic exercise (such as lifting and holding a heavy weight) only briefly but can sustain aerobic exercise (such as walking or swimming) for long periods? (Hint: Muscles have limited energy stores.)arrow_forwardCalmodulin 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?arrow_forwardA muscle is attempting to avoid being eaten by a starfish by tightly closing its shell. Is this an isometric contraction or an isotonic contraction? Explain.arrow_forward
- If a muscle cell’s sarcoplasmic reticulum had little to no Ca2+, could the muscle cell still produce an electrical impulse, and would the muscle cell still contract? Explain.arrow_forwardWith 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.arrow_forwardRigor mortis (the stiffening of muscles fibers several hours after death) is directly due to the depletion of what energy source? This energy molecule is used to power a calcium pump that transports Ca2+ ions back into the endoplasmic reticulum where calcium ions are already at a high concentration.arrow_forward
- Which of the following is NOT a stock form of the key molecules for energy generation in muscle? A. Creatine phosphate B. Hemoglobin C. Glycogen D. Myoglobinarrow_forwardDuring evolution, skeletal muscle became adapted to functional de-mands ranging from sudden, withdrawal movements of a startled worm, to the sustained contractions required to maintain mammalian posture, to supporting a long, fast chase across an African savanna. What are some of the fiber types in vertebrate muscle that evolved to support these kinds of activities?arrow_forwardWhat event causes a troponin-tropomyosin complex to regain its original shape in muscle relaxation? a. stimulation of ACh receptors b. diffusion of Na+ back into transverse tubules c. return of Ca2+ into the sarcoplasmic reticulum d. breaking of the bond with tropomyosinarrow_forward
- Impairment of intracellular calcium homeostasis in muscle fibers lead to chronic, severe muscle dysfunction. Impaired Calcium ATPase activity can lead to abnormal, persistent elevation of intracellular calcium concentrations. Explain how persistently high intracellular calcium concentration would affect cross-bridge formation, and muscle contractions, and muscle tension? (Mention the effects on the steps involved cross bridge formation, and muscle contraction/relaxation cycle, and overall muscle tension).arrow_forwardUnlike skeletal muscle smooth muscle Mayer spontaneously contract when it is. What feature of smooth muscle allows it to stretch without immediately resulting in a strong contraction?arrow_forwardRecently, it has been observed that several muscle diseases and disorders are linked to problems with triad structure and function.One such disorder is called malignant hyperthermia, a dire hypermetabolic response to certain inhaled anesthetics such as halothane. Muscles become very rigid due to excessive contraction (especially the masseter muscle), the body temperature spikes, andmuscles break down. Death is certain if not treated. Given the principal symptoms of malignant hyperthermia, what is its likely cause?Propose a theoretical mechanism for a treatment that would dampen the deleterious effects of this disorder.arrow_forward
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