The plasma membrane is selective because it has to be able to determine what is vital to the body or what is dangerous and unable to be received. Specifically the plasma membrane is a part of the cell that is contained of lipids and proteins. It is the regulation center of the cell and it's operation is functional to a living organism.
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Answer:
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Answer:
monoallelic gene expression
Explanation:
<em>Monoallelic expression is a type of gene expression where only a copy out of the two copies of a gene is expressed and the other is silent. </em>
A gene is usually represented by two alleles representing alternate forms of the same character. Individuals inherit an allele each from their two parents for every gene within their genomes.
When only one of the alleles is expressed for a particular gene while the other allele remains silent, such phenomenon is referred to as monoallelic gene expression.
Answer :Erwin Chargaff a Biochemist
Explanation:
He formulated the base paring of double helix of DNA. He reasoned that since the percentage of four DNA bases are of this proportions in human;
Adenine=30.9% and Thymine =29.4%;
Guanine=19.9% and Cytosine =19.8%
Then, the amount of adenine will always be equal to thymine,
And the amount of Guanine equals to cytosine based on this percentages of distribution.
(Adenine and Guanine are large, molecule of Purines, while thymine and Cytosine are Pyrimidine)
He concluded (although scientist believed, he did not explicitly stated this) that this should be the base paring patterns in DNA molecule. This is the first Chargaff Rule.
His second rule is that the DNA composition, in the relative amount of the four bases Adenine, Thymine, Cytosine and Guanine varies in proportion from one organisms to another. And this is the basis of molecular diversity.
Condensation, which is the process by which water vapor is changed back into liquid water. Then precipitation occurs.