DNA Chemistry

Question 1

What 4 nitrogenous bases are used in DNA?

Answer 1

Adenine, guanine, cytosine, and thymine

Question 2

What 4 nitrogenous bases are used in RNA?

Answer 2

Adenine, guanine, cytosine, and uracil

Question 3

What is the shape of a purine base?

Answer 3

Double ring

Question 4

What is the shape of a pyrimidine base?

Answer 4

single ring

Question 5

What does acid form when hydrolyzing DNA and RNA?

Answer 5

purine bases, pyrimidine nucleosides, sugar moiety, and phosphates

Question 6

What does base hydrolysis form with DNA and RNA?

Answer 6

DNA is resistant to base hydrolysis.

RNA forms nucleoside monophosphate

Question 7

What direction are the DNA double helixes?

Answer 7

Right

Question 8

Where are polar groups in the DNA helix?

Answer 8

Phosphates project outward to interact with proteins. Negatively charged phosphates make complex with Na, Ca, and K to stabilize the helix

Question 9

Where are non-polar groups in the DNA helix?

Answer 9

The interior of the molecule because they are extremely hydrophobic

Question 10

What force contributes greatly to helix stability due to the closeness of the nitrogen bases

Answer 10

Van der Waals

Question 11

What base pairing has a stronger bond: AT or GC?

Answer 11

GC due to the double bonds

Question 12

What is the distance for (1) one complete turn and (2) between stacked nitrogenous bases?

Answer 12

1) 3.4nm

2) 0.34 nm

Question 13

How many bases are in each conformation of DNA?

Answer 13

A—11 (tilted bases relative to long axis)
B—10
C—9 (probably doesn’t occur in vivo)
Z—12 (is a left helix)

Question 14

Hypochromic effect

Answer 14

Tightly stacked bases are less likely to be altered by UV rays

Question 15

Southern Blotting

Answer 15

DNA sample, used for gene structure/complexity

Question 16

Northern Blotting

Answer 16

RNA sample, used to measure mRNA levels

Question 17

Western Blotting

Answer 17

Protein sample

Question 18

What is necessary to create a DNA library

Answer 18

Vectors

Question 19

Ligation

Answer 19

Joining of DNA via phosphodiester bonds

Question 20

What allows DNA to be packaged into a bacteriophage protein coat?

Answer 20

COSmids

Question 21

Non repetitive DNA sequence frequency

Answer 21

Usually where transcription takes place

Question 22

Why are histones base proteins?

Answer 22

Have high levels of arginine and lysine

Question 23

Octamer

Answer 23

The core of 8 histones that DNA wraps around

Question 24

From which histone are solenoid structures formed?

Answer 24

Histone 1

Question 25

What does the acetylation or phosphorylation of histone amino acids do?

Answer 25

Decreases histone to DNA interactions, relaxing the chromatin

Question 26

What type of plasmid DNA travels the fastest in agarose gel electrophoresis?

Answer 26

Tightly bound DNA (supercoiled)