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 <em>correct</em> answer is:
Penicillium
Aspergillus
The lesson states:
If you've ever heard of or taken penicillin to fight off an infection, you can thank a member of the imperfect fungi called penicillium. Some mold species of penicillium are also important in the flavoring and aging of cheese. Roquefort and Camembert cheese owe their distinctive flavors to these fungi. Aspergillus is an imperfect fungus that is found on decaying food. It also contributes to the production of organic acids like citric acid. <u>Both penicillium and aspergillus produce enzymes that are purified and used in various industrial compounds and in medicine.</u>
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Answer:
Yes, Mass Extinctions May Have Been Caused By Meteors, as the probability of mass extinction occurring after an asteroid that could hit a random location on the Earth's surface was approximately 13% when the Chicxulub-scale asteroid hit the Earth.
Soot could be the main cause of mass extinction after an asteroid impact.