Nucleotide Structure Flashcards
(26 cards)
What are nucleotides and their composition?
They are monomers of nucleic acids
composed of a nitrogenous base, sugar, and phosphate.
Nitrogenous base types
they are either:
Purines (5,6 carbon ring)(numbered anti clockwise )
Pyrimidines (6 carbon ring)(numbered clockwise)
Purine and Pyrimidine Structure
DNA and RNA purine base
- Adenosine
- Guanine
RNA pyrimidines
- Uracil
- Cytosine
DNA pyrimidine
- Thymine
- Cytosine
Nucleosides
Composed of a nitrogenous base and sugar
if the sugar is ribose (RNA)
if the sugar is 2-deoxyribose (DNA)
Naming ribonucleosides
(-ine) Adenosine Guanine uridine Cytosine
Naming 2-deoxyribonucleoside
(doex-) Deoxyadionsine DeoxyThymidine (thymidine) Deoxycytosine Deoxyguanine
Other purines produced during metabolism
Hypoxanthine
xanthine
uric acid (Adenine and guanine metabolism)
Type of Sugar
Pentose 5 carbon sugar
RNA (Ribose sugar) Hydroxyl group in 2 and 3 position
DNA (Deoxyribose sugar) Hydroxyl group only in 3 position
Characteristic of Phosphate groups
A strong acid that gives the nucleic acid their acidity.
Phosphate group attachment
c3 or c5 but mostly c5
Linkage of the sugar with a purine or pyridine base through…
N-glycosidic linkage
Purine c1-n9
Pyrimidines c1-n1
Nucleotides
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
linkage of the nucleoside with the phosphate group happens through…
Ester linkage at oh on c5 sugar
Functions of Nucleotides
- 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)
More than 1 phosphate group linkage
by high energy bonds
Linkage of the back bone of the nucleic acid
phosphodiester bond between c5 of deoxyribose and c3 of another
nucleic acid
polynucleotide which store and express all the information necessary for building and maintaining life
DNA
repository of the genetic information, chemical bases of heredity, and found of genetic diseases
RNA
regarded as a vectors and translator of the information
DNA structure
right handed double stranded molecule, held in register by hydrogen bonds between purines and pyrimidines bases. helical structure
Amount of hydrogen linkage between guanine and cytosine
3 hydrogen bonds
Amount of hydrogen linkage between adenine and thymidine
2 hydrogen bonds
Amount of hydrogen linkage between adenine and uracil
2 hydrogen bonds
Two grooves in the helical structure of DNA
major groove
minor grooves for the regulatory proteins to bind with specific nucleotide sequence without disrupting the base pairing
