No matter what the cell type, prokaryotic or eukaryotic, plant or animal, the cell membrane forms a protective barrier between the exterior environment and the interior of the cell.
Answer:
- Calcium binds to troponin C
- Troponin T moves tropomyosin and unblocks the binding sites
- Myosin heads join to the actin forming cross-bridges
- ATP turns into ADP and inorganic phosphate and releases energy
- The energy is used to impulse myofilaments slide producing a power stroke
- ADP is released and a new ATP joins the myosin heads and breaks the bindings to the actin filament
- ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, starting a new cycle
- Z-bands are pulled toward each other, shortening the sarcomere and the I-band, producing muscle fiber contraction.
Explanation:
In rest, the tropomyosin inhibits the attraction strengths between myosin and actin filaments. Contraction initiates when an action potential depolarizes the inner portion of the muscle fiber. Calcium channels activate in the T tubules membrane, releasing <u>calcium into the sarcolemma.</u> At this point, tropomyosin is obstructing binding sites for myosin on the thin filament. When calcium binds to troponin C, troponin T alters the tropomyosin position by moving it and unblocking the binding sites. Myosin heads join to the uncovered actin-binding points forming cross-bridges, and while doing so, ATP turns into ADP and inorganic phosphate, which is released. Myofilaments slide impulsed by chemical energy collected in myosin heads, producing a power stroke. 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. Finally, Z-bands are pulled toward each other, shortening the sarcomere and the I-band, producing muscle fiber contraction.
Answer : Option B) Swifts earlier attempts at nonsatirical essays and speeches had failed to elicit a response from the government.
Explanation : Jonathan Swift chose a satirical essay to address the issues of Ireland's poor in A Modest Proposal as his previous attempts to get a response from the government was failed and not fruitful. He thought of approaching in a satirical way so that he can pin-point the issues to the government in humorous way.
Since all of the three beetle species posses the protein, we can use it to determine their relations. We can study the sequence of the amino acids that make the protein and the 3D structure of the protein. The more differences there are in amino acid sequences and the structure of the protein, the species are more distantly related because they have diverged a long time ago and their genes that produce that protein have undergone many changes over time.
