Muscle Contraction Lab Report

608 Words3 Pages
Manassa Philip
BIOL 282
Section #16395

Muscle Physiology 1
The purpose of this lab is to become familiar with muscle tissue and to test what substances are necessary for muscle contraction and whether or not muscles can in fact contract without the presence of Ca+.
Because muscle contractions require both ATP and Calcium ions to be present, I hypothesize that neither solution A, B, or C will cause the muscle fiber to contract.
Muscle contraction occurs when a stimulus causes acetylcholine, a neurotransmitter, to be released. This will then generate an electrical impulse that enters the t-tubules and Sarcoplasmic Reticulum that will then release Calcium ions ( Ca+). Once the calcium has been released in the sarcoplasm, it will then bind to the troponin causing it to shift and expose
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The muscle fiber had an initial length of 1.4 cm and after adding the solution B, the length decreased to 1.2cm. This means that the muscle fiber contracted by 0.2cm while the muscle fibers treated with solutions A or C stayed at the initial length. The muscle contraction was not an expected result because it is known that both ATP and Ca+ are required in muscle contraction, however there was no Ca+ present in the experiment. So, why did the muscle contract? Because the muscle fiber was placed in glycerol before having added one of the three solutions, Ca+ is not required for muscle contraction. In any normal muscle fiber, the Calcium ion is required to bind to the tropomyosin to free the active site on the actin, however this muscle fiber was placed in glycerol and glycerol denatures troponin and tropomyosin so calcium is not needed for the contraction to take place. With ATP alone the muscle was able to contract. The K+ and Mg+ ions are both salts which help strengthen the bond between actin and myosin, resulting in a stronger

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