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:
D. rigidity and shape that's why in plants they stand upright for photosynthetic process.
The answer is false, liquid molecules continue to move even after the concentration is uniform.
Diffusion happens because there’s a concentration gradient between the dye and the water, therefore dye molecules moves to the water area. But note that this is only the net movement of the molecules, which means, even if more molecules are moving towards water, there are still some dye molecules that are moving in the opposite direction.
So, after the concentration is equal, the motion of the dye molecules does not stop, they still move in random directions, but there’s no net movement instead, as there’s no concentration gradient. Remember molecules are always moving in all directions , it just depends on whether there’s a net movement or not. If there’s no net movement, the amount of molecules moving to each and every direction is always equal.
Answer:
b because I learned it in 4th grade
Explanation:
b
