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:
Grass
Explanation:
since producer is the first thing in the food chain its grass
Answer:
water is an abiotic factor
<h2>Energy allocation in penguin</h2>
Explanation:
- Although penguins don't grow from year to year, they increase and decrease in size as they repeatedly form and use energy stores,a significant amount of energy might be stored in fat during part of the year but be missing from the pie chart because it is used later in the year
- Allocation of limited endogenous resources causes trade-offs between competing traits, such as reproduction, somatic growth and maintenance
- During food deprivation, animals cannot maximize all of their life-history traits and must exhibit adaptive behavioral, physiological and biochemical responses to reduce metabolism and/or the cost of current activities in order to maintain biological value
