What is DNA and why is this molecule important? A. DNA – Deoxyribonucleic Acid B. Codes for our traits
Why is the structure of DNA important? Structure must be able to be: • A “blueprint” for our traits • Easily copied
What does DNA look like? 1953 – James Watson and Francis Crick discovered structure of DNA; later won Nobel Prize
What does DNA look like? • “Twisted ladder” or “Spiral Staircase” • Double helix • 2 connected strands wrapped around each other
Sugar + phosphate + base = 1 nucleotide What is DNA made of? A. Sugar “Deoxyribose” B. Phosphate C. Base
Four different nucleotides • Deoxyribose • Phosphate • Base - Adenine • Deoxyribose • Phosphate • Base - Thymine • Deoxyribose • Phosphate • Base - Cytosine • Deoxyribose • Phosphate • Base - Guanine
DNA is shaped like a ladder RAILS RAILS RUNGS
DNA is shaped like a ladder Nucleotides are connected so: • Rails are alternating sugar - phosphate • Bases are pointed to center
DNA is shaped like a ladder DNA is made of: • Two strands • Strands connect at bases
Basepair rules - Adenine always connects with Thymine • Cytosine always connects with Guanine
Code of Life - Order of bases spells out a code for your traits. • Sequences of DNA which code for a trait are called “genes”. • Change the order of the bases (mutation) and you may have a new trait.
Fun DNA Facts • DNA is 1/10th width of human hair, but DNA in each cell is 6 feet long (over 3 billion nucleotides)! • If all DNA from one person were connected end to end, it would stretch from the Earth to the Sun – 4 times!
Humans and Mice – 85% identical Fun DNA Facts • Every person’s DNA sequence is unique (forensics, paternity tests). • BUT . . . sequence is 99.8% IDENTICAL to any other person! • Humans and Bananas – 50% identical
Fun DNA Facts • Why is the DNA sequence of every living thing have almost the same DNA sequence? • All are made of cells • Cell division • Making nutrients
Fun DNA Facts • Only 2% of our DNA codes for genes. Rest is . . . • “junk DNA” that may come from viruses!
Review Animations • DNA structure review • Base pair review • DNA structure review #2