Lecture 3

Question 1

Name the 3 components of a nucleotide

Answer 1

phosphate (part of the back bone)

Sugar (Ribose or Deoxyribose)

Nitrogenous base (purine or pyrimidine)

Question 2

State the significance of the C1 carbon in ribose/deoxyribose

Answer 2

Where the base attaches via glycosidic bond

Question 3

State the significance of the C2 carbon in ribose/deoxyribose

Answer 3

where OH means RNA and H means DNA

Question 4

State the significance of the C3 carbon in ribose/deoxyribose

Answer 4

phosphodiester bond to the phosphate backbone occurs here

C3 and C5 are involved in the bonding between the sugar and phosphate

Question 5

State the significance of the C4 carbon in ribose/deoxyribose

Answer 5

Is the O in the ring of both RNA and DNA

Question 6

State the significance of the C5 carbon in ribose/deoxyribose

Answer 6

Where the PO4- attaches

C3 and C5 are involved in the bonding between the sugar and phosphate

Question 7

Compare C-3prime-endo and C-2prime-endo structures of nucleotides

Answer 7

the nitrogenous base is linked to the carbon next to C3 in C-3prime-endo structure

the nitrogenous base is linked to the carbon next to C2 in C-3prime-endo structure

Question 8

In DNA purines always base-pair with ________, which creates what type of helix?

(fill in the blank and answer the question)

Answer 8

Pyrimidines

this creates an antiparallel double helix

Question 9

What direction does in vitro oligonucleotide synthesis occur?

Answer 9

3 prime to 5 prime

Question 10

Which helix structure of DNA is most physically relevant to humans?

Answer 10

B DNA

Question 11

___ DNA conformation is seen primarily in RNA

Answer 11

A (A DNA)

Question 12

name the 3 types of DNA conformation that can be artificially induced based on salt content and the solvent being used.

Answer 12

A DNA

C DNA

Z DNA

Question 13

name the 3 types of DNA conformation that can be artificially induced based on salt content and the solvent being used.

Answer 13

A DNA

C DNA

Z DNA

Question 14

Verbally describe conservative, Semi-conservative, and dispersive models of DNA replication

Answer 14

Conservative results in one completely new double helix and the old double helix

Semi-conservative results in 2 helices, each with one old and one new strand of DNA

Dispersive results in alternating stripes of old and new DNA in each double helix

Question 15

How are hairpins and cruciform structures of DNA created? what do they require?

Answer 15

they are created by superhelical strain

they require palindromic sequence (inverted repeat)

Question 16

Describe Triplexes and what they require/how they form.

Answer 16

basically a portion of DNA that is triple stranded

requires a homopurine-homopyrimidine duplex

They use Hoogsteen hydrogen bonds to form

Question 17

Describe Quadruplexes. Include what they are composed of and where they occur.

Answer 17

a portion of quadruple stranded DNA

Composed of Guanines only

Occur at telomeres and some promoters

Question 18

Describe Quadruplexes. Include what they are composed of and where they occur.

Answer 18

a portion of quadruple stranded DNA

Composed of Guanines only

Occur at telomeres and some promoters

Question 19

Use an equation to describe the melting temperature of a substance. Also describe the melting temperature of a substance in terms of the substance being denatured.

Answer 19

The temp. at which DeltaG = 0

The temp. at which 1/2 of the sample is denatured (single strands instead of double strands)