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:
Assuming the dominant allele is represented as A, and the genotype as AA and the recessive as a, and genotype as aa; then the F1 will produce the offispring. Aa, Aa, Aa,Aa in ratio: 1:1:1:1:1
This shows the dominance of allele A.
However if two of the F1 generation are crossed then:
The F2 is AA,Aa,Aa,aa the phenotypic ratio is
3 ; 1
W<u>hile the Genotypic ratio is ratio;</u>
<u> 1AA : 2Aa Aa; 1aa(1 ;2;1)</u>
Explanation:
Answer:
The main properties of water are its polarity, cohesion, adhesion, surface tension, high specific heat, and evaporative cooling.
Explanation:
The main properties of water are its:
- polarity
- cohesion
- adhesion
- surface tension
- high specific heat
- evaporative cooling
Answer:
"Long, bitterly cold, dry winters and short, cool, damp summers define the boreal forest climate. The boreal forest is alive with activity. In the winter, their conical forms decrease snow buildup on branches, preventing them from breaking under the weight of the snow."
Explanation:
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