Chemical Composition of DNA

Components•Five-carbon sugar (pentose) called deoxyribose•Phosphate group•Nitrogenous base

classification:purines (G and A)pyrimidines (C and T)

How is the DNA Chemically Designed to Perform its Role as Genetic Material?DNA•Deoxyribonucleic Acid•Storage facility of genetic information (genes)• It is replicated during synthesis phase of interphase before a cell divides.•Provides mechanism for chromosome duplication.

What Is the Central Dogma of Molecular Genetics?

DNA

RNA PROTEIN

Transcription

ReverseTranscription

Self-replicationloop

Lab conditions

Self-replicationloop

DNA Replication: DNA TO DNAComplementary Base Pairing• C pairs with G, and vice versa•A pairs with T, and vice versa

DNA Replication

TAC CTG TAG AGG CTC TTC ATG CAG AAG ATC

ATG GAC ATC TCC GAG AAG TAC GTC TTC TAG

Old Strand

New Strand

Transcription: DNA to RNA

TAC CTG TAG AGG CTC TTC ATG CAG AAG ATC

AUG GAC AUC UCC GAG AAG UAC GUC UUC UAG

One Strand DNA

mRNA

Transcription: DNA to RNA

Translation: RNA to Protein

UAC CUG UAG AGG CUC UUC AUG CAG AAG AUCtRNA

Final pairing/last strand

AUG GAC AUC UCC GAG AAG UAC GUC UUC UAGFinal pairing

met – asp – ile – ser – glu – lys – tyr – val – phe – stop

Genetic Code

What is the Role of DNA in Heredity?•Some genes provide instructions for the production of building blocks of the body, such as keratin in hair and in skin. Some genes code for the production of melanin that gives brown color to skin, eyes and hair, amylase for starch digestion or hormones like insulin for regulation of blood sugar.