Answer:
I think A but I might be wrong good luck
The answer to this question would be: <span>(2) cytoplasm
The nucleus is the organelle in middle of the cell that contains DNA. The ribosome is organelle that has a function in protein synthesize. Mitochondrial has a function in making the energy. Cytoplasm is water inside the cells. Everything would be stored inside it and moving material will need to pass it.</span>
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.
There are two main reasons why cells divide rather than continuing to grow larger and larger. One of the main reason is that the larger cell become more demanding, therefore the large cell will increase load on the machinery of the cell such as DNA. The other reason is that if the cell grow too large it will be difficult for the cell to move for nutrients and discard the waste across the cell membrane. Also the surface area for each cell will also be reduced, which is required for active functionality of a cell.
