The correct answers are:
- Methylation of histone tails in chromatin can promote condensation of the chromatin.
- DNA is not transcribed when chromatin is packaged tightly in a condensed form.
- Acetylation of histone tails is a reversible process.
- Some forms of chromatin modification can be passed on to future generations of cells.
- Acetylation of histone tails in chromatin allows access to DNA for transcription.
Histone modifications are post-translational modifications of histone protein that can affect gene expression by altering chromatin structure or recruiting histone modifiers.The most common modifications are methylation, phosphorylation, acetylation and ubiquitylation. All of them affect the binding affinity between histones and DNA and thus loosening (gene activation) or tightening (gene repression) the condensed DNA.
Histone methylation is a transfer of methyl group by histone methyltransferases to lysine or arginine amino acid of protein. Effect of methylation depends on the type of protein that is modified. Demethylation is the reverse process.
Histone acetylation is the process of adding of an acetyl group(by histone acetyltransferases) to histone proteins and it can also activate or inhibit the gene expression. Deacetilation is reverse process.
Answer:
If it is a gene mutation then it is during the S phase, and if it is a chromosome mutation, then during metaphase or anaphase.
Explanation:
The building block of nucleic acids are nucleotides. These consist of sugar, a phosphate, and a nitrogenous base.
Fossils should be your answer
Fossils usually are bones, as bones are strong, and can last for long amounts of time without breaking down.
hope this helps
My Answer: RNA molecules
Why?: " <span>Catalysts with this special self-promoting property can use raw materials to reproduce themselves and thereby divert these same materials from the production of other substances."
Hope I helped! :D</span>
