Nucleotide Structure

Question 1

What are nucleotides and their composition?

Answer 1

They are monomers of nucleic acids

composed of a nitrogenous base, sugar, and phosphate.

Question 2

Nitrogenous base types

Answer 2

they are either:
Purines (5,6 carbon ring)(numbered anti clockwise )
Pyrimidines (6 carbon ring)(numbered clockwise)

Question 3

Purine and Pyrimidine Structure

Answer 3

DNA and RNA purine base

• Adenosine
• Guanine

RNA pyrimidines

• Uracil
• Cytosine

DNA pyrimidine

• Thymine
• Cytosine

Question 4

Nucleosides

Answer 4

Composed of a nitrogenous base and sugar
if the sugar is ribose (RNA)
if the sugar is 2-deoxyribose (DNA)

Question 5

Naming ribonucleosides

Answer 5

(-ine)
Adenosine 
Guanine 
uridine
Cytosine

Question 6

Naming 2-deoxyribonucleoside

Answer 6

(doex-)
Deoxyadionsine
DeoxyThymidine (thymidine)
Deoxycytosine
Deoxyguanine

Question 7

Other purines produced during metabolism

Answer 7

Hypoxanthine
xanthine
uric acid (Adenine and guanine metabolism)

Question 8

Type of Sugar

Answer 8

Pentose 5 carbon sugar
RNA (Ribose sugar) Hydroxyl group in 2 and 3 position
DNA (Deoxyribose sugar) Hydroxyl group only in 3 position

Question 9

Characteristic of Phosphate groups

Answer 9

A strong acid that gives the nucleic acid their acidity.

Question 10

Phosphate group attachment

Answer 10

c3 or c5 but mostly c5

Question 11

Linkage of the sugar with a purine or pyridine base through…

Answer 11

N-glycosidic linkage
Purine c1-n9
Pyrimidines c1-n1

Question 12

Nucleotides

Answer 12

composed of a nucleoside with a phosphate group

results from the linkage of 1 or more phosphates with a nucleoside into oh group at c5 of the sugar

Question 13

linkage of the nucleoside with the phosphate group happens through…

Answer 13

Ester linkage at oh on c5 sugar

Question 14

Functions of Nucleotides

Answer 14

• Structural (DNA and RNA)
• Biological transducer of free energy (ATP, GTP)
• Important components of coenzymes (FAD, NAD+, NADP+, coenzyme A)
• second messenger (c-AMP, c-GMP)
• Synthesis of ceramide (Cytosine derivatives CTP)
• UDP-glucoronic acid (drugs aspirin )
• Adenosine 3’ phosphate 5’ sulphophosphate
• UDP-glucose
• S-adenosylmethionine (methyl donor)

Question 15

More than 1 phosphate group linkage

Answer 15

by high energy bonds

Question 16

Linkage of the back bone of the nucleic acid

Answer 16

phosphodiester bond between c5 of deoxyribose and c3 of another

Question 17

nucleic acid

Answer 17

polynucleotide which store and express all the information necessary for building and maintaining life

Question 18

DNA

Answer 18

repository of the genetic information, chemical bases of heredity, and found of genetic diseases

Question 19

RNA

Answer 19

regarded as a vectors and translator of the information

Question 20

DNA structure

Answer 20

right handed double stranded molecule, held in register by hydrogen bonds between purines and pyrimidines bases. helical structure

Question 21

Amount of hydrogen linkage between guanine and cytosine

Answer 21

3 hydrogen bonds

Question 22

Amount of hydrogen linkage between adenine and thymidine

Answer 22

2 hydrogen bonds

Question 23

Amount of hydrogen linkage between adenine and uracil

Answer 23

2 hydrogen bonds

Question 24

Two grooves in the helical structure of DNA

Answer 24

major groove

minor grooves for the regulatory proteins to bind with specific nucleotide sequence without disrupting the base pairing

Question 25

who determined the double helix structure of DNA

Answer 25

j. Watson and S. Crick in 1953

took the noble prize at 1962 Watson, Crick, and M. Wilkins

Question 26

Features of Watson and Crick Model

Answer 26

• two helical polynucleotide chains coiled right handed
• chains are antiparallel
• bases are on the inside
• phosphate and deoxyribose on the outside
• planes of the bases and perpendicular to the helix axis
• a single turn contains 10 base pairing
• two chains are held together by hydrogen bonding
• base pairing are specific
• two strands are complementary