DNA replication goes in the 5' to 3' direction because DNA polymerase acts on the 3'-OH of the existing strand for adding free nucleotides. DNA replication can take place both the directions chemically. ... But these nucleotide triphosphates hydrolyze spontaneously under aqeuous conditions.
Answer: b. Acetyl Co-A
Explanation:
Acetyl CoA produced through pyruvate, amino acids, and fatty acids are oxidized in the Krebs cycle in CO2, obtaining as products NADH, FADH2 and GTP (ATP). Parallel to this oxidation, the Krebs cycle produces compounds used as precursors for biosynthesis. As it is a cycle, an oxaloacetate molecule could, in principle, oxidize an amount indefinite of acetyl CoA. Acetyl-CoA is formed from the oxidative decarboxylation of pyruvate, sequentially performed by pyruvate dehydrogenase -PDH (complex multi enzymatic of 3 enzymes), in the mitochondrial matrix.
Answer: a. Genetic recombination (crossing over)
b. Can also be explained in terms of crossing over
c. Non disjunction of homologous chromosomes in meiosis 1
Explanation:
The process that allows for the transfer of both the paternal and maternal materials to is the crossing over process that takes at meiosis 1 changing them to secondary spermatocytes. While they are still primary spermatocytes, they are still diploid cells having both the maternal and paternal chromosomes. But since the spermatozoon is an haploid cell, it is able to retail some of both parents chromosome by the crossing over event which takes place between homologous paternal and maternal chromosomes allowing them to exchange materials. Thus the chromosomal contents of the primary spermatocyte differs from that of the spermatozoon.
C. This can occur as a result of the one of the homologous chromosome pair refusing to separate at meiosis 1 with one gamete containing 4 chromosomes/8 sister chromatids and the second having 2 chromosomes/4 sister chromatids.
