Feb 6

Question 1

Which is planar and very nearly planar from pyrimidines and purines?

Answer 1

Purines are nearly planar, pyrimidines are planar

Question 2

For G-U base pairing, in DNA or RNA is easier, how many H bonds, but equivalent to what? Called what pair?

Answer 2

It is easier in RNA. It has 2 H bonds, but G and U need to rotate, so equivalent to 1 Hbond. Called wobble pair

Question 3

What is the ribose pucker, which form in DNA and RNA?

Answer 3

It is when have C2 or C3 endo, so sticking up on same side as the DNA base. DNA have 2’ endo mostly, RNA has 3’ endo mostly.

Question 4

In the glycosidic bond, carbon 1 of sugar bonds with which nitrogen # of pyrimidines and purines?

Answer 4

C1 of ribose with N1 of pyrimidines and N9 of purines

Question 5

Which of purines and pyrimidines can have syn and/or anti glycosidic bonds?

Answer 5

Purines can have syn or anti, so base is above ribose or flipped out. Pyrimidines only have anti

Question 6

Why do we get ribose pucker?

Answer 6

Because other bonds in the polynucleotide rotate freely, but glycosidic bond oot so much/.

Question 7

DNA B form has what type(s) of glycosidic bond orientations, what handed helix, parallel or anti parallel strands in helix, what type of pucker?

Answer 7

B form has 2’ endo sugar pucker, ONLY anti-glycosidic bonds, R handed helix, antiparallel strands

Question 8

What form are double stranded helices of RNA?

Answer 8

Mostly A form

Question 9

Adenosine is found in what coenzymes?

Answer 9

In CoA, NAD+, FAD+

Question 10

What atoms of adenine and cytosine can bacteria and eukaryotes methylate?

Answer 10

Bacteria methylate N6 of adenine, and N on C4, and C5 of cytosine. Eukaryotes methylate cytosine on 5th carbon