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.
Whats the question in this?
<u>Answer:</u>
ATP or the Adenosine Triphosphate is the energy currency of the living world, which transfers energy from one organic molecule to other, even from one cell organelle to other.
<u>Explanation:</u>
The functional group of ATP is phosphate which is quite evident from its name.
Adenosine diphosphate is the parent molecule. During either photophosphorylation or the respiration, the Inorganic phosphate molecule that is present in the cellular fluid gets attached to the parent molecule ADP via a high energy bond which is broken to give energy to the normal reactions.
<span>The answer is B.mRNA codons are joined by tRNA anticodons to assemble amino acids to form a protein. According to the central dogma of molecular biology, DNA sequence specifies RNA sequence which specifies protein sequence. DNA sequence is first copied into mRNA sequence during transcription. Later, during translation, mRNA codons are joined by tRNA anticodons to assemble amino acids to form a protein</span>
tRNA-precursors were smaller than the modern tRNA and their primary function was to participate in the formation of new structures by joining two or more RNA molecules.
The adaptor hypothesis is the explanation of how information could be extracted from a nucleic acid into a string of amino acids in a specific sequence. The proposed explanation involved recognition between the adaptor (today tRNA) and the template nucleic acid .
