DNA and RNA Stuctures

Question 1

What do nucleotides (monomeric units) consist of?

Answer 1

Base (Nitrogen Base), Phosphate Group, 5-carbon sugar

Question 2

What is the backbone connected by?

Answer 2

Phosphodiester linkages

Question 3

Double Helix

Answer 3

two helical strands that are coiled around a common axis

Question 4

What orientation are the strands in the double helix in?

Answer 4

anti-parallel

Question 5

Where is the sugar-phosphate backbone located on the helix?

Answer 5

Outside

Question 6

Where are the purine/pyrimidine bases located on the helix?

Answer 6

Inside

Question 7

Are the base pairs parallel or perpendicular to the helix axis?

Answer 7

perpendicular

Question 8

How many bases does it take to complete one “turn?” (rotation of 360 degrees)

Answer 8

10.4

Question 9

How many angstrom’s does it take to complete one turn?

Answer 9

34 (Base pairs are separated by 3.4 angstroms)

Question 10

What is the diameter of a helix?

Answer 10

20 angstroms

Question 11

What holds the base pairs together by?

Answer 11

Hydrogen Bonds

Question 12

What does base pairing facilitate?

Answer 12

1. Stability of DNA helix

2. Formation of Major and Minor Grooves

Question 13

What is the purpose of major grooves?

Answer 13

To expose a larger “surface” of the base(pair) for sequence specific recognition.