Answer:
Power stroke (myosin head bends) coupled with the release of ADP and phosphate
Explanation:
Muscle contraction results from myosin heads adhering to actin and attracting it inwards. It uses ATP. Myosin adhers to actin at a binding site of its globular actin protein and adheres at another binding site for ATP (hydrolyzed ATP to ADP, Pi and energy)
ATP binding prompts myosin to detach from actin, ATP is changed to ADP and inorganic phosphate, Pi by ATPase. The energy formed at this process orientates myosin head to a “cocked” direction.
The myosin head goes in the direction of the M line, holding the actin with it in the process causing the filaments to orientate nearly 10 nm in the direction of the M line--- power stroke (force is produced), the sarcomere reduces in length and the muscle contracts.
Note: The power stroke is seen when ADP and phosphate disattaches itself from the myosin head.
At the terminal point of the power stroke, the myosin head as low-energy, followed by ADP release.
The attached image shows the cross-bridge muscle contraction cycle, which is activated by Ca2+ sticking to the actin active site. And how actin moves in relation to myosin.
Answer:
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Explanation:
Beekeeping is affected by adverse climatic conditions and availability of floral resources. This study aimed to survey and characterize the flora in São João do Piauí, a semi-arid region in Piauí, Brazil, and to identify species providing resources to bees. Flowering plants were observed for 18 months, and records were taken of flowering date, growth habit, visitation and resources collected by bees. Melissopalinological analysis of honey produced in the area was performed. A total of 67 flowering plant species were recorded, of which 49 were considered as bee plants, with a predominance of herbs and shrubs. The low rainfall reduces the number of flowering species, which makes important the conservation and multiplication of species which bloom in dry season, such as Ipomoea glabra, Myracrodruon urundeuva, Sida cordifolia and Ziziphus joazeiro, as well as species that contribute to honey production such as Mimosa tenuiflora, Mesosphaerum suaveolens and Croton sonderianus.
Answer:
environmental stochasticity, and demographic stochasticity.
Explanation:
The small population species are prone to extinction. Due to the process of evolution, many species raised from a single species. This is because of variation, different individuals came and survive. But all the species can't achieve reproductive success. They also can't adapt to the changing environment. The changing of the environment in the biodiversity is called stochasticity. The fewer Populus species can't face the natural selection. As a result, their mortality rate is more and the natality rate is high. Sometimes demographic stochasticity also responsible. The fewer reproduction results in less number of the individual over time. This causes mass extinction. The extinction of dinosaurs is an example of mass extinction. The more reproduction of the species means more variety. They can better adapt to the changing environment. Some of the extinct animals are also living and known as living fossils. e.g. Armadillo, Platypus. The changing biodiversity and randomness of the population cause the extinction of a small population.
The membranes of various organelles in the endomembrane exhibits variances in their lipid and protein compositions. These differences are largely established by the function of the Golgi apparatus in modifying, sorting, and directing membrane components to their final end point.
