Ans.
Chromatin molecules are made up of DNA and histone proteins. Modification of chromatin structure include covalent, post-translational changes in histone proteins, present in chromation. Acetylation and methylation are two important histone modifications that affect structure of chromatin molecules.
Acetylation involves addition of an acetyl group to histones that increases transcription of DNA by loosen the association between DNA and nucleosome.
Methylation involves addition of a methyl group to histones that results in condensation of chromatin molecule and thus, decreases transcription of DNA.
Both acetylation and methylation are reversible processes.
Many chromatin modifications are genetic, means they can pass from one generation to another generation, called epigenetic modifications.
Thus, options B), C), D), E), and F).
Answer:
<em>Exceptions to Mendel's principles:
</em>
Does exceptions mean that Mendel was "wrong"? The answer is "NO". It means that we know more today about diseases, genes, and heredity than compared to what he expalined 150 years ago. Here I have summerized the exceptions with examples:
<em>Incomplete dominance</em>: When an organism is heterozygous for a trait and both genes are expressed but not completely.
<em>Example</em><em>:</em> SnapDragon Flowers
<em>Codominance</em>: When 2 different alleles are present and both alleles are expressed.
<em>Example</em>: Black Feathers + Whites feathers --> Black and white speckled feathers
<em>Multiple alleles</em>: Three or more alternative forms of a gene (alleles) that can occupy the same locus.
Example: Bloodtype
<em>Polygenic traits</em>: more than one gene controls a particular phenotype
Example: human height, Hair color, weight, and eye, hair and skin color.
Answer:
D.
Explanation:
It's the only choice that has three things that are made out of aluminum.
<em>Hope this helps :)</em>
I say the answer to your question is False because Day and Night are caused by the rotation on its axis!
