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.
I would say that your correct answer is B
A-The composition of their cell walls
Explanation: plant cell walls components is glucose. Fungi cell will components is chitin
Experts are rarely able to distinguish between two people handwriting. This is FALSE. Reason here is that a person can identify for two different people.
2. There are often no specific tests that can be used to definitely prove that something has been forged. This is TRUE. there is no specific prove that something has forged.
3. Documents examiners have have an easy time in obtaining exemplars because most people volunteer them. This is FALSE because there is no easy way to obtain exemplars of documents.
4. All typewriters and related devices will have variations in the type over time as the typewriter experiences wear and tear to its parts. This is TRUE because typewriters and other devices will not have variations of tear and wear to its parts.
Answer:
Biotechnology allows farmers to grow more food on less land using farming practices that are environmentally sustainable. Through biotechnology: Seeds yield more per acre, plants naturally resist specific insect pests and diseases, and farming techniques improve soil conservation.
Explanation:
