Answer: The calcium ion binds to troponin, and this slides the tropomyosin rods away from the binding sites.
Explanation:
Contraction and relaxation of muscle cells brings about movements of the body. The contractile myofilament called sarcomeres are bounded at each end by a dense stripe called the Z - line, to which the myosin fibres are attached, and lying in the middle of the sarcomere are the actin filaments, overlapping with the myosin.
When action potential spreads from the nerve along the sarcolemma (muscle cell membrane), it penetrates deep into the muscle cell through the sarcoplasm (cytoplasm of muscle cell), and releases CALCIUM from the intracellular stores.CALCIUM triggers the binding of myosin to the actin filament next to it forming CROSS BRIDGES.
For this to occur, ACTIN BINDING SITE has to be made available. TROPOMYOSIN is a protein that winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin. The first step in the process of contraction is for calcium ions to bind to troponin so that tropomyosin can slide away from the binding sites on the actin strands.
The answer is B) 4IF3 Hope this helps!
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The answer should be altitude
is a functional unit that results from interactions of abiotic, biotic, and anthropogenic components and are a combination of interacting, interrelating parts that form a unitary whole. Ecosystems vary in size. They can be as small as a puddle, or as large as the earth itself. Basically, any living and non-living things interacting together can be considered an ecosystem. Within each ecosystem, there are habitats that vary in size. A habitat is a place where a population lives. A population is a group of living organisms of the same kind living in the same place at the same time. Natural ecosystems are made up of abiotic factors such as air, water, rocks, and energy and biotic factors such as plants, animals, and microorganisms.
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Larger
During the process of breathing, the diaphragm contract by moving
downward and upward and this process usually increase or decrease the space in
the chest cavity. However, intercostal muscles between the ribs also help to enlarge
the chest cavity or reduce the space in the chest cavity.
