Active transport, which occurs at the expense of energy.
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.
Charles Darwin, is the scientist is the father of evolution
Coral reefs are built by coral polyps as they secrete layers of calcium carbonate beneath their bodies. And inside each coral poly lives single-celled algae called zooxanthellae. So basically in simplistic terms, coral polys create coral reefs and algae is in coral polys which also goes into coral reefs when they are made.
Answer:
This is through the process of methylation and phosphorylation of histones tails.
Explanation:
The addition of a methyl group to the amino acid of the histones of the nucleosomes that compacted DNA in the nucleus is called mehtylation, while the addtion of phodpahte is phosphorylation
Its effects on gene expression depends on the number of <u> methyl groups, and type of amino acid that methylated. During transcription. </u>
<u />
The DNA double strands are compacted and therefore hidden from transcription factors and enzymes of transcription by the hitones tails of the neuclosomes, Methylation weaken the binding bonds between the tails and DNA structure ; thereby aiding the uncoiling of DNA from the tails.(nucleosomes).This chemical reaction aided DNA strands exposure to transcription factors and enzymes, for initiation of transcription. This explains the dyanmic activity of methylation
Futhermore phophorylation also favours unwrapping of DNA, by imitating modifying enzymes e.g H3Y41E and H3T45E and convert it to→→ H3Y41phopspahte to aid DNA unwrapping and accessibility to transcription factors and RNA polymerase Enzymes,
