Chapter 6.1

Question 1

What is a nucleoside

Answer 1

• a five carbon sugar(pentose) bonded to a nitrogenous base

- >covalently link the base at carbon 1 to the nitrogen base

Question 2

Why are ATP/ADP compounds considered high energy?

Answer 2

-because of the energy associated with repulsion of the negative charges on the phosphate groups

Question 3

Why is there polarity within the DNA backbone

Answer 3

• because each strand has distinct 5 prime and 3 prime ends
• > 5 prime might have a phosphate group or an OH group
• > 3 prime might just have a free OH group on it on the Carbon 3

Question 4

Are both purines and pyramidines heterocycles

Answer 4

-yes

Question 5

How many hydrogen bonds between adenine and thymine? How many between guanine and cytosine?

Answer 5

Between adenine and thymine
->you got two

Between guanine and cytosine
->you got three

Question 6

What is the right handed helix of DNA referred to as?

Answer 6

• it is referred to as B-DNA

- >makes a turn every 3.4 nm and contains about 10 bases within that span

Question 7

What is the left handed helix of DNA referred to as?

Answer 7

• it is referred to as Z-DNA
• > makes a turn every 4.6 nm and contains baout 12 bases within that span

-note Z-DNA is highly unstable and difficult to research

Question 8

What are common ways to denature DNA?

Answer 8

-heat, alkaline pH and chemicals like formaldehyde and urea

Question 9

How does reannealing occur?

Answer 9

• if the denaturing conditions are removed

- >single stranded DNA can be paired up again

Question 10

What are the four requirements for aromatic compounds

Answer 10

• it is an unusually stable ring system
  1) The compound is cyclic
  2) The compound is planar

3) The compound is conjugated
- >conjugated means alternating single and multiple bonds, or lone pairs, creating at least one unhybridized p rbital for each atom in the ring

4)The compound has 4n+2 pi electrons(Huckel’s rule)