Answer:
The correct answer is 3: "<em>High levels of Ca2+ are expected to be found </em><em>within the sarcoplasmic reticulum</em>".
Explanation:
Muscular contraction is a highly regulated process that depends on free calcium concentration in the cytoplasm. Amounts of cytoplasmic calcium are regulated by <u>sarcoplasmic reticulum</u> that functions as a storage of the ion.
When a nerve impulse reaches the membrane of a muscle fiber, through acetylcholine release, the membrane depolarizes producing the entrance of calcium from <u>extracellular space</u>. The impulse is transmitted along the membrane to the sarcoplasmic reticulum, from where calcium is released. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. The calcium channel in the sarcoplasmic reticulum controls the ion release, that activates and regulates muscle contraction, by increasing its cytoplasmic levels. When <em>calcium binds to the troponin C</em>, <em>the troponin T alters the tropomyosin by moving it and then unblocks the binding sites,</em> making possible the formation of <em>cross-bridges between actin and myosin filaments.</em> When myosin binds to the uncovered actin-binding sites, ATP is transformed into ADP and inorganic phosphate.
Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
I believe this is translation and it occurs in the mRNA strand due to proteins call the initiation, elongation and release factors.
If it contians 1/16th the amount, it must have gone through 4 half lives: 1> 1/2> 1/4> 1/8> 1/16>.since the half-life of c-14 is about 5730 years, the age of the fossil is 4 X 5730 years or about 22,920 years old.
Answer:
Lysosomes are membrane-bound vesicles produced by the Golgi apparatus that contain DIGESTIVE enzymes.
Explanation:
Such as glycosidases, proteases and sulfatases.
It loses alot of soil minerals as a result of no availability of green plants
