Chapter 11- Structure of Nucleic Acids

Question 1

Nucleotides are linked between

Answer 1

5’ and 3’ phosphodiester linkages

Question 2

Why is RNA less stable than DNA

Answer 2

OH on 2’ makes the 3’ position in RNA more susceptible to non-enzymatic base-catalyzed cleavage

Question 3

First Parity rule

Answer 3

A%= T%
G% = C%

Question 4

Second Parity Rule

Answer 4

%purines= %pyrimidines in a single strand

Question 5

How many base pairs per turn (3.4 nm)

Answer 5

10.5 bp

Question 6

DNA stacking is stabilized by

Answer 6

hydrophobic interactions

Question 7

Base stacking has to do with the

Answer 7

stability of the helix

Question 8

RNA can base pair with complementary

Answer 8

RNA or DNA (paired strands are also anti-parallel)

Question 9

Pwptidyl transferase activity is performed by the

Answer 9

rRNA (not the associated proteins)

Question 10

Heat denaturation is:

Answer 10

reversible ( DNA melting)

Question 11

Unstacked bases have a higher _____ than stacked bases in helix

Answer 11

absorbance (due to disruption of electronic interactions between stacked bases)

Question 12

Unzipping DNA is like unzipping a zipper in what way?

Answer 12

starts difficult but becomes easier as it goes along

Question 13

Why does it take more heat to unzip GC bonds than it does with AT bonds

Answer 13

Harder to break 3 bonds than 2.

Question 14

Native structure

Answer 14

H bonding is satisfied through base pairing

Question 15

Denatured structure

Answer 15

Most H-bonds are satisfied through water

Question 16

Energetic contribution from H-bonds is the _____ in the native and denatured structures

Answer 16

Same

Question 17

Do H bonds stabilize the native structure relative to the denatured state

Answer 17

NO

Question 18

Why is denaturation favored among bases?

Answer 18

DNA is negatively charged at neutral pH (Charges repel each other)

Question 19

Net charge on nucleotide monophosphate

Answer 19

-2

Question 20

Net charge on a nucleotide monophosphate bound to a pentose

Answer 20

-1

Question 21

Molecule that contains a phosphoanhydride bond

Answer 21

UDP