Nucleic Acids Flashcards
Nucleic acids are found in
nucleus and are acidic in nature
True or false: a nucleic acid is a monomer
False
The monomer units of a nucleic acid are
nucleotides
What are the two types of nucleic acids?
DNA: Deoxyribonucleic Acid and RNA: Ribonucleic Acid
DNA :
Found
Function
Transportation
Found within cell nucleus
– Storage and transfer of genetic information
– Passed from one cell to other during cell division
RNA:
Occurs where
Primary function
Occurs in all parts of cell
– Primary function is to synthesize the proteins
*The components of a nucleotide
– Pentose Sugar - Monosaccharide – Phosphate Group (PO43-)
– Heterocyclic Base
Pentose Sugars – Ribose (RNA) vs. 2-Deoxyribose (DNA)
Ribose is present in RNA and 2-deoxyribose is present in DNA
• Structural difference:
– a —OH group present on carbon 2’ in ribose – a —H atom in 2-deoxyribose
• RNA and DNA differ in the identity of the sugar unit in their nucleotides.
Nitrogen-Containing Heterocyclic Bases
Bases
Pyrimidine derivatives
Purine derivatives
There are a total five bases (four of them in most of DNA and RNAs)
• Three pyrimidine derivatives - thymine (T), cytosine (C), and uracil (U)
• Two purine derivatives - adenine (A) and guanine (G)
• Adenine (A), guanine (G), and cytosine (C) are found in both DNA and RNA.
• Uracil (U): found only in RNA
• Thymine (T) found only in DNA.
Phosphate
Phosphate - third component of a nucleotide is derived from phosphoric acid (H3PO4)
• Under cellular pH conditions, the phosphoric acid is fully dissociated to give a hydrogen phosphate ion (HPO42-)
*Nucleotide Formation
The formation of a nucleotide from sugar, base, and phosphate can be visualized as a 2-step process
*The pentose sugar and nitrogenous base react to form a
Nucleoside
*The Nucleoside reacts with a phosphate group to form a
Nucleotide
*Nucleoside
A compound formed from a five-carbon monosaccharide and a purimone or pyrimidine base derivative. – The N9 of a purine or N1 of a pyrimidine base is attached to C- 1’ position of sugar (Beta-confirmation) – N-glycosidic linkage
– It is a condensation reaction (H2O released)
*There are 8 nucleosides associated with nucleic acid chemistry.
– Four ribonucleosides– RNA
– Four deoxyribonucleosides – DNA
*Nomenclature of nucleoside formation
– For pyrimidine bases – suffix -idine is used (cytidine, thymidine, uridine)
– For Purine bases – suffix -osine is used (adenosine, guanosine)
– Prefix “-deoxy” is used to indicate deoxyribose present (example: deoxythymidine)
*Nucleotide Formation
Addition of a phosphate group to a nucleoside
– Attached to C5” position through a phosphate-ester bond
– Condensationreaction(H2Oreleased)
– Named by appending 5’-monophosphate to nucleoside name
*Adenine DNA : Abbreviation Nucleoside Nucleotide Abbreviation
Abbreviation: A
Nucleoside: Deoxyadenosine
Nucleotide: Deoxyadenosine 5’ monophosphate
Abbreviation: dAMP
*Guanine DNA: Abbreviation Nucleoside Nucleotide Abbreviation
Abbreviation: G
Nucleoside: Deoxyguanosine
Nucleotide : Deoxyguanosine 5’ monophosphate
Abbreviation: dGMP
*Cytosine DNA: Abbreviation Nucleoside Nucleotide Abbreviation
Abbreviation: C
Nucleoside: Deoxycytidine
Nucleotide: Deoxycytidine 5’ Monophosphate
Abbreviation: dCMP
*Thymine DNA: Abbreviation Nucleoside Nucleotide Abbreviation
Abbreviation: T
Nucleoside: deoxythymidine
Nucleotide: Deoxythymidine 5’ Monophosphate
Abbreviation: dTMP
*Adenine RNA: Abbreviation Nucleoside Nucleotide Abbreviation
Abbreviation: A
Nucleoside: Adenosine
Nucleotide: Adenosine 5’ Monophosphate
Abbreviation: AMP
*Guanine RNA: Abbreviation Nucleoside Nucleotide Abbreviation
Abbreviation: G
Nucleoside: Guanosine
Nucleotide: Guanosine 5’ Monophosphate
Abbreviation: GMP
*Cytosine RNA: Abbreviation Nucleoside Nucleotide Abbreviation
Abbreviation: C
Nucleoside: Cytidine
Nucleotide : Cytidine 5’ Monophosphate
Abbreviation : CMP