San Diego State University DNA Structure and Analysis MCQs

I’m working on a genetics question and need the explanation and answer to help me learn.

 answer some questions on this topic of genetics 

Which is NOT a major feature of the Watson and Crick DNA model?coiled strands form a right-handed double helixstrands are paired by hydrogen bonds between complementary basesa complete turn is 10 Angstromschains run antiparallelcontains major and minor grooves

Spleen diesterase is an enzyme that breaks the covalent bond that connects the phosphate to the 5′ carbon. Assume that the dinucleotide in the accompanying figure is digested with spleen diesterase. To which base and to which carbon on the sugar is the phosphate now attached?A, 3’A, 5’none of theseT, 5’T, 3′

Assume that a culture of E. coli was grown for approximately 50 generations in 15N (provided in the medium in the ammonium ion), which is a heavy isotope of nitrogen (14N). You extract the DNA from the culture, and it has a density of 1.72 gm/cm3. From the literature, you determine that DNA containing only the common form of nitrogen, 14N, has a density of 1.70 gm/cm3. Bacteria from the 15N culture were washed in buffer and transferred to 14N medium for one generation immediately after which the DNA was extracted and its density determined. What would you expect the density of the individual strands of DNA in the denatured extract to be? For the purposes of this question, assume that DNA has the same density regardless of whether it is single- or double-stranded.Group of answer choices1.72 gm/cm31.70 gm/cm31.70 and 1.72 gm/cm31.71 gm/cm31.70 and 1.71 gm/cm3

A common biological molecule composed of a deoxyribose with a nitrogenous base attached is a(n) ________.oligonucleotidenucleoside monophospateribonucleotidenucleosidenucleotide