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:
DNA
Explanation:
The Roles of DNA, Genes, Alleles, and Chromosomes in Inheritance. Explain that the information passed from parents to offspring is transmitted by means of genes which are coded in DNA molecules. Explain the basic process of DNA replication.
<span>Which type of immunity defends against any type of invader?
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Answer : Nonspecific
Answer:
In a fair test two or more things are compared. In order for a test to be fair or scientifically sound, children are required to ensure only one thing (this is called a variable) is changed.
For example, if testing which material is the most waterproof by pouring liquid onto a selection of different materials, in a fair test only the type of material (the component you are testing) should be changed. Therefore all other elements (the type of liquid used, the amount of liquid used, the distance the liquid is poured from, the speed at which it is poured and the size of the material) must remain the same each time the test is carried out. It would be unfair or an unscientific test if, for example, 1000ml of water were poured onto a piece of foil and 2ml of milk poured onto a piece of foam – you would not be able to fairly compare the materials.
hope this will help you!!!.....
Based on what i know of bats they have echo location to help them navigate were they are going and the echo location helps them to find food.a special feature that they have to help them survive is their hearing do to their lack of eye sight they compensate with unnatural hearing.
