Answer:
by the sarcoplasmic reticulum's calcium ion pumps
Explanation:
Rigor mortis or postmortem rigidity, is a state caused by chemical changes in the muscles that occur post mortem and cause the limbs of the corpse to stiffen.
This occurs because after death, there is no cellular respiration and consequently, no oxygen nor ATP (ATP is required for the muscle relaxation).
Calcium enters the cytosol after death because it is released due to the deterioration of the sarcoplasmic reticulum and due to the breakdown of the sarcolemma. Ca2+ ions activate the formation of actin-myosin cross-bridging necessary for the contraction. Muscles are unable to relax, because myosin heads continue to bind with the active sites of actin and there is no ATP to destabilize the myosin-actin bond.
Answer:
AUG GCU GGG AGG AAU
Explanation:
A point mutation that would not affect the protein is one that has the same mRNA codon. The answer choices indicate that the third part is affected. The normal mRNA would be GGC, which if you look at the table, is gly. The other sequences that match are GGU, GGC, GGA, and GGG. The only answer choice that matches is the third one, with GGG.