Exotic species do not have a niche in the ecosystem that they are in. Therefore they take up resources that native species rely on to survive. Exotic species also have no natural predators in that environment causing them to flourish and multiply quickly.
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: b. Webbed-toed mice survived better and reproduced more than mice without webbed toes.
Explanation:
Natural selection is a phenomenon that suggests that organisms that have a better structural and morphological advantage over the others have better chances of survival over the others.
The webbed toed mice have a survival advantage over the without the webbed toes because this can help the webbed toed mice to swim. The webbed toed trait will be beneficial and passed on to the next generation of the mice and the webbed toed mice will reproduce more than the mice without webbed toes.
Answer:
a. body cells
Explanation:
Body cells are eukaryotic. Eukaryotic cells replicate via mitosis.
Answer:
A gamete containing an extra chromosome is formed.
Explanation:
Geminal mutations may result in the production of mutant gametes. If such gametes fuse with those from another individual of the opposite sex to form a zygote, the mutation is transmitted to the progeny. A trisomy gamete containing an extra chromosome would transmit the mutation to the offspring after fertilization.
