C. there is an equal amount of day and night everywhere on earth.
Answer:
False
Explanation:
The histones that are more positively charged, tight hardly to negatively charged DNA. So, enzymes, such as acetyltransferases, that reduce the positive charge of histones promote transcription.
Chromatin structure and its modifications can change the package of the DNA and consequently, alter the gene expression. The most common modifications of the chromatin are covalent modifications such as acetylation/deacetylation (by acetyltransferases and eacetylases), methylation (by methyltransferases), and phosphorylation (by kinases). This is the way of gene expression regulation.
The effects of modifications are different, for example methylation promotes condensation of the chromatin and as a consequence, prevents binding of transcription factors to the DNA (transcription is repressed).
Acetylation loosens the association between nucleosomes and DNA (because it neutralizes the positive charge of histones) and consequently promotes transcription. Deacetylation is a process opposite to acetylation.
Answer:
R r
R RR Rr
r Rr rr
Explanation:
1:2:1 is the genotypic ratio
The reactive CARBONYL GROUP, contributes to the ability of aldehydes and ketones to be involved in energy reactions. Aldehydes and ketones undergo different types of reactions that lead to various products. One example of these reactions are nucloephilic reactions which lead to the production of alcohols, alkenes, diols, imine, etc.
Answer: Options A, B, C and D are correct.
Explanation: They can trigger the activity of histone acetyltransferases.
These RNAs functions by binding to histone-modifying complexes, to DNA binding proteins (including transcription factors), and even to RNA polymerase II.
They can silence genes by promoting the formation of euchromatin by arranging hetero- or euchromatic regions into close proximity may stabilize these domains or it may control the spreading of post-translational modifications (PTMs) to nearest chromatin.
They are actively involved in X chromosome inactivation.
They can regulate the translation and stability of mRNAs.
In Eukaryotic cells RNA transcription is a closely regulated process. Transcription of a lncRNA may regulate the transcription of nearby mRNA genes, either positively (maintaining active chromatin structure) or negatively (for example, colliding polymerases). In these cases, the RNA product may have no importance at all, or it could have an additional function.
