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:
i hope it will help u bestie
Explanation:
Each year, many people look forward to the winter solstice, which usually falls on December 21 and is the shortest day of the year, because they know after that, there will be progressively more daylight each day.
Answer:
a) False.
b) True.
c) False.
d) True.
e) False.
f) True
g) True.
Explanation:
a) The main characteristic of homologous chromosomes is that they have an equal size. There is a difference in size on both chromosomes.
b) In number one, two chromosomes are homologous. In number two also two chromosomes are homologous. On the other hand, the chromosomes at number one and two are different. Each chromosome has two sister chromatids.
c) A DNA molecule has a double helix, that is, two chains. When a DNA chain is broken and a chromatide has a DNA chain, then two chromatids make up a chromosome and a DNA chain, in this way there are eight dsDNA molecules
d) If each chromosome contains a centromere, therefore, there are four centromeres on all four chromosomes.
e) If a chromosome contains four telomeres, therefore there will be sixteen telomeres.
f) The function of cohesin is to regulate the separation of chromatids in the cell division process. When DNA replication is complete, the DNA compacts and condenses to form mitotic chromosomes.
g) The CENPA protein is encoded by the CENPA gene.
Ribosomes nuclear membrane nucleus large cauole
Answer:
The activity factor was modified. Ambulating indicates that the person is active. Even small activities require energy. So, people who can walk around and aren’t bedridden expend more calories than people who need to be on bedrest all day. Also, when the stress factor was changed to severe infection, the caloric requirement increased. This increase is probably because the immune system requires more energy to fight off the infection
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