Nutrients cross the membrane wall with the help of protein channels.
There may be a shortage of clean drinking water in the future
Answer:a compound present in the body as a neurotransmitter and a precursor of other substances including epinephrine
Explanation:
DNA is condensed by a certain amount just on its own, just by its own interactions within the DNA molecule,..but whne proteins get involved it gets condensed 30000 fold
<span>what happens is that proteins called histones are like hockey pucks, and DNA wraps around it 1.5 times and then goes to another histone and wraps around that so that it looks like beads on a string (i hope that makes sense, its the only way to describe it) </span>
<span>these histones condense this DNA a lot, and when the histones get methylated then the DNA packs together even closer to get heterochromatin (VERY densely packed DNA)...the theory here is that DNA has a net negative charge due to the phosphate groups in the DNA backbone and doesnt allow the DNA to come together as closely as it could (like charges repel like charges), but when histones are methylated, the negative charge on the DNA is masked by the methyl groups and DNA can come together closer </span>
