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.
Answer:
The answer is C. Mother and Father
4. When you look up to the sky, it appears as a dark circle with halo light at its edges moving across the face of the sun. As it does, depending on the relative position of the person on earth – that determines where they are on the umbra or penumbra of the eclipse, the place becomes a daytime twilight (umbra) or partial twilight (penumbra).
5. A new moon is formed when the moon is in between the sun and the earth. This is converse to the case of a lunar eclipse where the earth is between the sun and moon. In a new moon, the face of the moon that is faced towards the earth is dark because it is not lit by the sun. It is important to note that a solar eclipse is not formed because the moon’s orbit, around the earth, is tilted at an angle.
Answer:
During DNA packaging, long pieces of double-stranded DNA are tightly looped, coiled, and folded so that they fit easily within the cell. Eukaryotes accomplish this feat by wrapping their DNA around special proteins called histones, thereby compacting it enough to fit inside the nucleus
the answer is D, I hope i helped <3
