BIOL 153 Chapter Notes -Protein Kinase C, Cellular Respiration, Cardiac Muscle

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blushmule307

30 May 2012

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Based on the lecture and text material, you should be able to do the following: muscle. Tni inhibitory subunit that binds to actin during relaxed state of muscle. Tnt helps tropomyosin position itself properly on actin during contraction. Tropomyosin rod-shaped protein which wraps around the actin core of the thin filament to help stiffen it in a relaxed muscle fiber, it blocks the active site of the actin so that a myosin head cannot bind. What is it? during contraction, thick and thin filaments do not change their length, but slide past each other (overlapping further) as a result, individual sarcomeres shorten myofibrils shorten the entire cell. What causes the asliding@ of the filaments? this concept is best understood if we break it down into steps: Muscle fibers are stimulated by the nervous system, causing an ap that propagates along the sarcolemma and down the t-tubules.

Related Questions

Describe the steps of how cross-bridge musclecontractions take place using the followinggeneral information

1) Action potential (generated by motor neuron) innervatesmuscle fiber

2) Motor neuron releases neurotransmitter (travels acrossneuromuscular junction), binds to muscle cell (sarcolemma)

3) Action potential in muscle fiber allows sliding ofmyofilaments (shortening of muscle cells)

Describe the process of skeletal muscle contraction by assembling the following 10 events in the proper order. Your answer must be written in complete sentences- do not just list the letters or the events- write it out. Begin your description with an action potential traveling down a motor neuron and end with the muscle in it's relaxed state.

A) T and T system undergoes a conformational change, exposing the myosin binding sites on actin

B) myosin heads/cross bridges bind to actin and flex, shortening the sacromere

C) the motor neuron triggers an action potential at the neuromuscular junction

D) calcium ions bind to the T and T system

E) actin filaments are pulled toward the center of the sacromere, shortening the muscle fiber

F) muscle fiber is stimulated at the neuromuscular junction

G) myosin head/cross-bridges bind to actin

H) APs travel down the T-tubules to the sarcoplasmic reticulum

I) in response to an AP, calcium ions are released into the cytosol/space around the myofibrils

J) calcium ions actively transported into the sarcoplasmic reticulum

K) myosin head continues to attach, flex, release, extend, and reattach as long as calcium ions are present

lilacporcupine860

there are 4 stages in muscle contraction: excitation, excitation-contraction coupling, contraction, and relaxation.
a) briefly describe the molecular process of excitation, beginning at the synaptic bulb of the neuron. how does this affect the muscle fiber?
b) how is calcium released from the sarcoplasmic reticulum during excitation-contraction coupling, and how do troponin and tropomyosin regulate the interaction between myosin and actin
c) describe the events of one cross-bridge cycle and how this shortens the sarcomere.
d) following contraction, what events must occur to allow the muscle to relax?

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BIOL 153 Chapter Notes -Protein Kinase C, Cellular Respiration, Cardiac Muscle

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