BIOCHEM - NUCLEOSIDES/NUCLEOTIDES

Nucleic Acid

unbranched polymers composed of repeating monomers called nucleotides.

Two types of nucleic acid

DNA

RNA

Deoxyribonucleic Acid

stores and passes genetic info

Ribonucleic Acid

carries and translates genetic info to make proteins

RNA’s Sugar

Ribose

DNA’s Sugar

Deoxyribose

Purine’s Nitrogen Base

Guanine (G) Adenine (A)

Pyramidines Nitrogen Base

Cytosine (C) Uracil (U) Thymine (T)

Pyrimidine base

Ends in -idine

Purine base

Ends with -osine

DNA Double Helix

Discovered by Watson and Crick

DNA Double Helix

Two strands run opposite directions

Base Pairs (2 Hydrogen Bonds)

A-T

Base Pairs (3 Hydrogen Bonds)

G-C

Replication

DNA makes a copy of itself

Semi-conservative

DNA has one old and one new strand

Transcription

DNA to mRNA

mRNA base pairs with DNA template

A-U, T-A, G-C, C-G

Translation

mRNA to Protein

mRNA

Carries codons (3 bases = 1 amino acid)

tRNA

Brings amino acid (has anticodon)

rRNA

Builds ribosomes

Steps of Translation

Initiation

Elongation

Termination

Start Codon

AUG

Stop Codon

UAA, UAG, UGA