DNA

RECALL … 4 classes of macromolecules –Carbohydrates –Lipids –Proteins –NUCLEIC ACIDS!!! –Subunit (Building Blocks): NUCLEOTIDES

DNA – deoxyriboNUCLEIC ACID (de – without, oxy – oxygen, ribo – ribose sugar) Store and pass genetic information Building Block of DNA: nucleotides

DNA Very longVery long thin molecule made up of linked nucleotides Double stranded helix –Twisted ladder Determines traits of EVERY LIVING ORGANISM

Nucleotide Structure 3 parts –Sugar (deoxyribose or ribose) –Phosphate (P with oxygens attached) –Nitrogen base Adenine Thymine Guanine Cytosine

Nitrogen Base Pairing Adenine Thymine Guanine Cytosine All Tigers Can Growl

Nitrogen Base Pairing Adenine Thymine Guanine Cytosine = Hydrogen Bond

Nitrogen Base Pairing Adenine Thymine CytosineGuanine ThymineAdenine CytosineGuanine AdenineThymine Guanine Cytosine = Hydrogen Bond

Nitrogen Base Pairing Adenine Thymine CytosineGuanine ThymineAdenine CytosineGuanine AdenineThymine Guanine Cytosine

What is the COMPLEMENTARY DNA STRAND? EXAMPLE 1 ATTGACCATTGATAGCCGAATA TAACTGGTAACTATCGGCTTAT EXAMPLE 2 TCTTCGGAACATTAGTCGAGGC AGAAGCCTTGTAATCAGCTCCG

CHROMATID DNA ladder DNA double helix Chromatin Coiled up Chromatin 2 Chromatids

CHROMOSOME Chromatin 2 Chromatids 2 Chromatids = 1 Chromosome

Centromere Holds sister chromatids together in a chromosome

Chargraff’s Rule There will be the same number of bases as its complementary base in a DNA molecule. –EX: If there are 80 Adenines then there will be 80 Thymines. – If there is 20% A’s, then how many G’s will there be in a DNA molecule? 30% G’s Why? –Because if there are 20% A’s, then there must be 20% T’s = 40%. –100% - 40%= 60% left for C’s and G’s. –So, 30% for C’s and 30% for G’s.