Friday, July 31, 2009

Mendel's observations?

Mendel observed that genes for different traits do not influence the inheritance of other traits. That observation is known as...





a. Codominance


b. The Law of Dominance


c. The Law of Independent Assortment


d. Incomplete dominance


e. The Law of Segregation

Mendel's observations?
Law of Independent Assortment
Reply:the principle of independent assortment





According to the principle of independent assortment, different pairs of alleles are passed to offspring independently of each other. The result is that new combinations of genes present in neither parent are possible. For example, a pea plant's inheritance of the ability to produce purple flowers instead of white ones does not make it more likely that it will also inherit the ability to produce yellow peas in contrast to green ones. Likewise, the principle of independent assortment explains why the human inheritance of a particular eye color does not increase or decrease the likelihood of having 6 fingers on each hand. Today, we know this is due to the fact that the genes for independently assorted traits are located on different chromosomes .
Reply:The key to a rational treatment of elementary Mendelian genetics, specifically to an understanding of the origin of dominant and recessive traits, lies in the facts that: (1) alleles of genes encode polypeptides; (2) most polypeptides are catalysts, i.e. enzymes or translocators; (3) the molecular components of all traits in all cells are the products of systems of enzymes, i.e. of fluxing metabolic pathways; (4) any flux to the molecular components of a trait responds non-linearly (non-additively) to graded mutations in the activity of any one of the enzymes at a catalytic locus in a metabolic system; (5) as the flux responds to graded changes in the activity of an enzyme, the concentrations of the molecular components of a trait also change


It is then possible to account rationally, and without misrepresenting Mendel, for: the origin of dominant and recessive traits; the occurrence of Mendel's 3(dominant):1(recessive) trait ratio; deviations from this ratio; the absence of dominant and recessive traits in some circumstances, the occurrence of a blending of traits in others; the frequent occurrence of pleiotropy and epistasis.





A rational explanation of Mendel's observations


. Quantifiable differences between any two forms of a trait


Implications of the systemic approach of Kacser and Burns





etc etc also there
Reply:Mendel only had 2 laws, the law of segregation and the law of independent assortment. The rest are out of the question.





Answer is C.





Mendel's law of segregation states that an allele will give rise to a gene expression and an allele is inherited from each side of the parent respectively. The dominant allele would show determine the phenotype of the organism.





The law of independent assortment states that the gene inheritence is not affected by other traits. This is also known as the 9:3:3:1 and 3:1 inheritence pattern.





So there you go, answer is C.


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