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:
Diversity of the community = 2.097
Explanation:
Given:
Number of pitch pines = 134
Number of douglas firs = 24
Number of red pines = 53
Find:
Diversity of the community
Computation:
Simpson's diversity index = N(N-1)/Σn(n-1)
Particular n n(n-1)
Pitch pine 134 17822
Douglas firs 24 552
Red pine 53 2756
Total N=211 21130
So,
D= [211(211-1)] / 21130
D = 2.097
Diversity of the community = 2.097
Transcription would not take place and the protein would not be produced.
Photosynthesis is the process that plants use to make food, Which requires sun light, minerals from the soil, water, and carbon dioxide. (They turn carbon dioxide to oxygen).
