Answer:
<h2>
Calcium ions</h2>
Explanation:
The actin and myosin are the myofilaments which are involved in the contraction and relaxation of the muscle. The actin is thin filaments and contains the attachment site for the myosin but the site is blocked by the tropomyosin and troponin proteins.
When calcium ions present in the muscle binds to the troponin molecules, it changes the conformation of the tropomyosin. This change exposes the attachment site of the myosin and then the myosin binds the troponin and causes Powerstroke and leads to contraction of a muscle.
Thus, Calcium ions is correct.
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Answer:
The atoms of each element have a characteristic number of electrons arranged in electron shells. The number of valence electrons determines what types of bonds or ions the atoms may form, so the chemical reactivity of an atom arises from its electron distribution. The properties of compounds emerge from the arrangement of their constituent atoms and of the bonds between them.
Thus, a wide variety of molecules with very different chemical properties can be made from the same basic atoms. Each molecule has a distinctive size, shape, and charge distribution, which determine its highly specific ability to interact with other molecules.
Compounds in chemical wastes may contaminate the environment if their atoms are combined in new arrangements that harm living organisms.
Explanation:
<em>Answer: The bases are the "letters" that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.</em>