Nucleosides and Nucleotides

What is DNA?

A polynucleotide that has specific sequence of deoxyribonucleotide units covalently linked by a 3’ - 5’ phosphodiester bond

What are genes?

Segments of double stranded DNA that usually coeds fro functional RNA and protein macromolecule

What are RNA molecules?

A polynucleotide that has specific sequence of ribonucleotide units covalently linked by a 3’-5’ phosphodiester bonds

Nucleosides

What

Structure

What: A base and ribose unit (NO PHOSPHATE)

Structure:

• Nitrogen contain base = purine or pyrimidine

  • Purine = double ring = adenine and guanine

  • Pyrimidine = single ring = cytosine, thymine and uracil

• A pentose

Nucleoside monophosphates

AKA

What

Attached how

Function

AKA: Nucleotides

What: A nucleoside with 1 phosphate attached

• By either at the 5’, 3’ or at 2’ -OH

Function:

• Ribonucleotides are the building blocks of RNA

  • Involved in energy currency, signal transduction and components of enzyme cofactors

• Deoxyribonucleotides are the building blocks of DNA

Nucleoside diphosphate

What

How attached

A nucleoside with 2 phosphates

• Phosphates are covalently attached to one another (alpha, beta)

Nucleoside triphosphate

What

How attached

A nucleoside with 3 phosphates

• Alpha, beta and gamma phosphates are covalently attached

What are the 4 nucleotides?

• Adenine

• Guanine

• Cytosine

• Thymine/uracil

What are the 4 nucleosides?

When nitrogenous bases attach to ribose or deoxyribose sugar =

• Adenosine

• Guanosine

• Cytidine

• Thymindine/uridine