<span>There are numerous proteins in muscle. The main two are thin actin filaments and thick myosin filaments. Thin filaments form a scaffold that thick filaments crawl up. There are many regulatory proteins such as troponin I, troponin C, and tropomyosin. There are also proteins that stabilize the cells and anchor the filaments to other cellular structures. A prime example of this is dystrophin. This protein is thought to stabilize the cell membrane during contraction and prevent it from breaking. Those who lack completely lack dystrophin have a disorder known as Duchene muscular dystrophy. This disease is characterized by muscle wasting begininng in at a young age and usually results in death by the mid 20s. The sarcomere is the repeating unit of skeletal muscle.
Muscle cells contract by interactions of myosin heads on thick filament with actin monomers on thin filament. The myosin heads bind tightly to actin monomers until ATP binds to the myosin. This causes the release of the myosin head, which subsequently swings foward and associates with an actin monomer further up the thin filament. Hydrolysis and of ATP and the release of ADP and a phosphate allows the mysosin head to pull the thick filament up the thin filament. There are roughly 500 myosin heads on each thick filament and when they repeatedly move up the thin filament, the muscle contracts. There are many regulatory proteins of this contraction. For example, troponin I, troponin C, and tropomyosin form a regulatory switch that blocks myosin heads from binding to actin monomers until a nerve impulse stimulates an influx of calcium. This causes the switch to allow the myosin to bind to the actin and allows the muscle to contract. </span><span>
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Answer:
A And D
Explanation:
I got it right and it isnt A and C
A hematocrit value of your blood would be lower than normal because your dehydrated, if you’re on an airplane without water your blood cells could lack latitude. (Hope this helps)
Both internal and external factors are capable of regulating the cell cycle of a specific type of cell (Option a).
<h3>What is the cell cycle?</h3>
The cell cycle refers to the period of life of a cell from which it is generated until its division (cytokinesis).
The cell cycle of a cell is regulated by internal factors such as cyclins and kinases that phosphorylate specific proteins as well as external factors that trigger the cell division (e.g. temperature conditions).
In conclusion, both internal and external factors are capable of regulating the cell cycle of a specific type of cell (Option a).
Learn more about the cell cycle here:
brainly.com/question/8283140
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