DNA Structure

DNA stands for... Deoxyribonucleic Acid

Chromosomes and DNA •DNA, genes, and chromosomes compose the molecular basis for heredity. •A chromosome is a structure in the nucleus of a cell consisting of one long thread of DNA that is tightly coiled

Genes and DNA • A gene is a specific location on a chromosome, consisting of a segment of DNA • Each chromosome consists of hundreds of genes determining the many proteins for an organism.

Discovering the structure of DNA • Discovered in 1953 by James Watson & Francis Crick - double helix; twisted ladder; spiral staircase

DNA Structure cont. Rosalind Franklin - XRay Defraction Image of DNA proved that it was a double helix/twisted ladder shape

Discovery of DNA Timeline

DNA: codes for your genes (traits) •made of repeating subunits called nucleotides

What is a nucleotide? Three components: 1. PHOSPHATE 2. DEOXYRIBOSE (sugar) 3. BASE (A,T,G,C)

Base-Pair Rule Adenine <==> Thymine Guanine <==> Cytosine The sides/backbone of the DNA ladder are phosphate & sugar held together by hydrogen bonds.

Base Pair Rule One side: A T A T C A T G C G G G Other side: