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>
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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,
Answer:
When homologous chromosomes form pairs during prophase I of meiosis I, crossing-over can occur. Crossing-over is the exchange of genetic material between homologous chromosomes. ... It results in gametes that have unique combinations of chromosomes. In sexual reproduction, two gametes unite to produce an offspring.
Explanation:
Answer: The blue colour of a biuret solution changes to violet.
Explanation: Biuret solution is a reagent that is used to test for the presence of protein in a substance.
A Biuret solution is composed of sodium hydroxide and copper II sulphate. Copper ions give the reagent its characteristic blue colour. Copper ions react with peptide bonds in the protein in an alkaline solution to form a Biuret compound with a violet colour. The copper ions which have two positive charges are reduced to a positive charge, thereby causing a colour change.
Cellulose : cell wall phospho : plasma membrane
strength : cell wall
selective membrane : plasma membrane
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