Lecture 20 - Nucleotide Structure

Question 1

The “acid” portion of DNA or RNA arise from _____.

Answer 1

the phosphate/phosphoric acid

Question 2

Nucleic acids are nucleotides attached to a _____.

Answer 2

sugar-phosphate backbone

Question 3

Describe the sugar-phosphate backbone

Answer 3

the 5’ phosphate group of one nucleotide is attached to the 3’ -OH of another nucleotide

Question 4

The sugar backbone is comprised of ______ bonds.

Answer 4

phosphodiester

Question 5

Describe the hydrogen bonding in base pairing of nucleotides

Answer 5

A2T; G3C

Question 6

The fully folded chromosome is found in what stage of mitosis?

Answer 6

the M-phase (chromosome segregation)

Question 7

Uncoiled DNA is found in what phase of mitosis?

Answer 7

The I-phase (interphase)

Question 8

Histone proteins + nuclear DNA is called _____.

Answer 8

chromatin

Question 9

What differentiates ribose from deoxyribose sugars?

Answer 9

Ribose has a C2 and C3 -OH group; Deooxyribose has only a C3 -OH group

Question 10

Bases + sugar = ______

Answer 10

nucleoside

Question 11

base + sugar + phosphate = _________

Answer 11

nucleotides

Question 12

Pyrimidines are the (large/small) ring stucture of nitrogenous bases.

Answer 12

small (Memory aid: big name, small ring)

Question 13

Memory aid for purine and pyrimidine:

Answer 13

Pure As Gold: Purine - adenine, guanine

Question 14

Reduces ribose sugars to deoxyribose sugars.

Answer 14

ribonucleotide reductase (removes C2 -OH group)

Question 15

Why is production of nucleotides a highly energy favorable process?

Answer 15

Most nucleotides exist as a triphosphate. Cleavage of 2 Pi release energy and forms a nucleotide

Question 16

Name and f(x)?

Answer 16

• Coenzyme-A
• synthesis and beta-oxidation of fatty acids - pyruvate oxidation

Question 17

Name and F(x)?

Answer 17

• NAD
• acts as an electron carrier in redox reactions to form NADH

Question 18

Name and F(x)?

Answer 18

• FAD
• Participates in redox reactions ot accept 2e to form FADH2

Question 19

DNA/RNA is synthesized in the ______ direction.

Answer 19

5’-3’

Question 20

Carbon 1 of sugar contains _____.

Answer 20

N-base

Question 21

Carbon 2 of sugar contains ______.

Answer 21

either -H or -OH (deoxy vs ribose sugar)

Question 22

Carbon 3 of sugar contains _____.

Answer 22

-OH group; forms phosphodiester bond with C5

Question 23

Carbon 5 of sugar contains ______.

Answer 23

Phosphate group (binds with C3 -OH to form phosphodiester bond)

Question 24

One turn of DNA is approximately ____ in length.

Answer 24

34 angstroms

Question 25

How may base pairs per turn?

Answer 25

10 (~ every 3.4 angstroms)

Question 26

What increased nucleotide ratio increases denaturation temperature? Why?

Answer 26

Increased G:C. Because G:C has 3 H-bonds, compared to the 2 H-bonds of A:T

Question 27

Coded for by viral genome. Assists in virus replication by making DNA from RNA

Answer 27

reverse transcriptase

Question 28

Enzyme that cleaves nucleic acid into oligomers (insert picture)

Answer 28

ribonuclease/deoxyribonuclease

Question 29

Cleaves phosphdiester backbone (insert picture)

Answer 29

phosphdiesterase

Question 30

Cleaves phosphate from nucleotide

Answer 30

nucleotidase (cleaves nucleotide to Pi and nucleoside

Question 31

Cleaves base from nucleoside

Answer 31

Nucleosidase

Question 32

Phosphodiesterase produces what oligomer?

Answer 32

nucleotide monophosphate (NMPs) or deoxynucleoside monophosphates (dNMPs)

Question 33

Phosphoric acid, ribose sugar, and base is called a ______.

Answer 33

nucleotide

Question 34

What same atom sources are shared between pyrimidines and purines?

Answer 34

Amino acids

Question 35

How do pyrimidine and purine carbon sources differ?

Answer 35

Pyrimidine: HCO3

Purine: CO2

(Longer N-base = “longer” carbon source)

Question 36

How do pyrimidine and purine THF sources differ?

Answer 36

Purine: formyl THF

Pyrimidine: methylene THF

Longer N-base = longer THF form

Question 37

Sugars are attached to nitrogenous bases by what type of linkage?

a) alpha-glycosidic linkage
b) beta-glycosidic linkage
c) delta-glycosidic linkage

Answer 37

b) beta-glycosidic linkage