Answer:
When a muscle cell contracts, the myosin heads each produce a single power stroke.
Explanation:
In rest, attraction strengths between myosin and actin filaments are inhibited by the tropomyosin. When the muscle fiber membrane depolarizes, the action potential caused by this depolarization enters the t-tubules depolarizing the inner portion of the muscle fiber. This activates calcium channels in the T tubules membrane and releases calcium into the sarcolemma. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. When calcium binds to the troponin C, the troponin T alters the tropomyosin by moving it and then unblocks the binding sites. Myosin heads bind to the uncovered actin-binding sites forming cross-bridges, and while doing it ATP is transformed into ADP and inorganic phosphate which is liberated. Myofilaments slide impulsed by chemical energy collected in myosin heads, <u>producing a power stroke</u>. The power stroke initiates when the myosin cross-bridge binds to actin. As they slide, ADP molecules are released. A new ATP links to myosin heads and breaks the bindings to the actin filament. Then ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, which starts a new binding cycle to actin. Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
Answer:
Fruiting body, If cut off, will hamper sexual reproduction in fungi.
<u>Explanation:</u>
Fungi are of unicellular, multinucleate, and multicellular. They can be classified based on their reproductive spores and their multinucleate or multicellular filaments nature that can be called as hyphae. The sporocarp that is also named as fruiting bodyor fruit body is a multicellular structure in which the spore-producing structures, like basidia or asci, are born.
The fungi consist of spores in the fruiting bodies, that are dispersed for reproduction process. Mushrooms common instance of a fruiting body. These are formed from hyphae, that are smaller threads that usually forms the bulk of fungi. The term mycelium that describes a hyphae network will be extending in all directions through the soil. Hence, when Fruiting body is cut off it will hamper sexual reproduction in fungi because there are many hyphae with which Fruiting body can be formed.
The build up in the child's ear prevent sound from reaching the eardrum.
Eucariotec like red blood cells and others
Procariote is like bacteria or amiba
Answer:
Geology means science that deals with the Earth's physical structure and substance, it's history and the processes that act on it.
