DNA Structure

Question 1

3 components of a nucleotide

Answer 1

Heterocyclic nitrogen base, A 5-carbon sugar called a pentose, phosphate group

Question 2

Which bases are purines and pyrimidines

Answer 2

Purines: Adenine, Guanine, 9-membered rings
Pyrimidines: Cytosine, Thymine, Uracil, 6-membered ring

Question 3

Difference between an RNA and DNA nucleotide

Answer 3

The sugar in DNA is a 2’-deoxyribose, which has no hydroxyl group on the 2’ carbon whereas the RNA has a ribose, which has a 2’ hydroxyl

Question 4

Nucleotide vs nucleoside

Answer 4

Nucleosides contain only sugar and a base whereas Nucleotides contain sugar, base and a phosphate group as well. A nucleotide is what occurs before RNA and DNA, while the nucleoside occurs before the nucleotide itself.

Question 5

What is a nucleotide

Answer 5

DNA or RNA unit that contains a sugar, base, and a phosphate group

Question 6

Which type of linkages connect nucleotides in nucleic acids?

Answer 6

Phosphodiester bonds covalently connect the nucleotide units in DNA and RNA

Question 7

Chargaff’s rule

Answer 7

C=G
A=T

Question 8

Describe the Watson-Crick DNA structure

Answer 8

Sugar-phosphate backbone, One helical turn ever 34 angstroms (10.5 bases), 3.4 angstrom distance of phosphodiester bond, major and minor groove, right handed double-helical arrangement

Question 9

What are the major and minor groove for in DNA

Answer 9

Where most interactions with proteins or other nucleic acids occur

Question 10

how do bases avoid water

Answer 10

Bases are hydrophobic, so they stack on top of each other in the center of the molecule by their most hydrophobic edges. (hydrophobic stacking)

Question 11

How does increased GC bases affect BP

Answer 11

GC bonds have 3 bonds resulting in stronger bonds between bases. Increases boiling point.

Question 12

IS DNA replication in humans conservative

Answer 12

semi-conservative