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:
362 nucleosomes
Explanation:
A nucleosome repeat is made up of the DNA (146 bp) wrapped around the core nucleosome particle and the linker DNA (110 bp as in this situation). We can conclude that, every repeat stands for 256 (146 + 110) base pairs of DNA.
We are given the length of the entire region to be 92,672 bp long,
To determine the number of nucleosomes to organize the region into the 10nm fiber structure
Let,
Number of nucleosomes =
the length of the entire region
------------------- -----
base pairs of DNA.
= 92,672
-------
256
= 362 nucleosomes
Therefore, 362 nucleosomes is needed to structure the region into the 10nm fiber structure.
Answer:
<h2>92%</h2>
Explanation:
When glucose is converted to ethanol by yeast, one mole of glucose is converted into two moles of ethanol and two moles of carbon dioxide,
and this process produce two moles of ATP.
C6H12O6 → 2 C2H5OH + 2 CO2
When glucose is converted to ethanol by yeast (as in the production of beer) 92% of the chemical energy that was originally stored in glucose still remains in the end product, ethanol, that is produced.
