CHEMICAL COMPOSITION OF DNA

Question 1

building blocks of DNA

Answer 1

nucleotides

Question 2

components of Nucleotides

Answer 2

Phosphate backbone (negatively charged); Pentose sugar and Nitrogenous bases ATGC - (basic)

Question 3

Nucleosides

Answer 3

precursor of Nucleotides: sugar and nitrogenous bases

Question 4

basic, flat aromatic rings with conjugated double bonds and multiple sites for hydrogen bonding

Answer 4

NITROGENOUS BASES

Question 5

bases that have double rings

Answer 5

PURINE (ADENINE AND GUANINE)

Question 6

bases that have one ring

Answer 6

PYRIMIDINE (THYMINE AND CYTOSINE)

Question 7

heterocyclic aromatic compound; pyrimidine fused with an imidazole ring (double ring)

Answer 7

PURINES (Adenine (6-aminopurine) and Guanine (2-amino-6-oxypurine)

Question 8

heterocyclic aromatic compound similar to benzene and pyridic(single ring)

Answer 8

PYRIMIDINE (Thymine (2,4-dioxy-5-methyl pyrimidine) , Cytosine (2-oxy-4-aminopyrimidine) and Uracil (2,4- dioxy-pyrimidine)

Question 9

rapid introconversion of isomeric forms

Answer 9

TAUTOMERIZATION OF BASES

Question 10

TRUE OR FALSE: Tautomerism leads to anomalous base pairing.

Answer 10

TRUE

Question 11

Formation of nucleotides

Answer 11

linked by covalent bonds, producing 2 water molecules

Question 12

Phosphoester bond

Answer 12

phosphate and sugar

Question 13

N-glycosidic bond

Answer 13

sugar and nitrogenous bases

Question 14

component of the backbone of the polynucleotide together with the pentose; imparts negative charge to the DNA

Answer 14

PHOSPHATE GROUPS

Question 15

The _____________ enable DNA to associate with proteins (e.g. histones - positively charged)

Answer 15

negative charge of phosphates

Question 16

linear sequence of deoxyribonucleotides; two complementary strands held together by hydrogen bonds; linked together by phosphodiester linkage

Answer 16

PRIMARY STRUCTURE

Question 17

double helix; two intertwined strands antiparallel to each other

Answer 17

SECONDARY STRUCTURE

Question 18

maximizes hydrophobic interactions for greater stability

Answer 18

Major and minor grooves

Question 19

distance between two base pairs

Answer 19

3.4 A

Question 20

helix diameter; maintained by the right-pairing of bases

Answer 20

20 A

Question 21

DNA Conformations

Answer 21

A, B, Z

Question 22

shorter, compacted nucleotides

Answer 22

A- DNA

Question 23

stretched form of DNA; absence of major groove

Answer 23

Z - DNA

Question 24

typical form of DNA

Answer 24

B - DNA

Question 25

there’s a lookout in the DNA; there is a sequence in DNA that has no pair

Answer 25

HAIRPIN DNA

Question 26

It protects the DNA from enzymatic attack

Answer 26

HISTONES

Question 27

Equilibribrium of Nitrogenous bases

Answer 27

Chargaff’s Rule

Question 28

TAUTOMERIZATION OF BASES

Answer 28

Keto-enol forms of guanine
Amino-imino forms of cytosine

Question 29

Distance between two base pairs

Answer 29

3.4 A

Question 31

Helix diameter

Answer 31

20 A

Question 32

Two complementary strands held together by

Answer 32

Hydrogen bonds