DNA Structure and Function

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: 1.A “blueprint” for our traits 2.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

What is DNA made of? A. Sugar  “Deoxyribose” B. Phosphate C. Base Sugar + phosphate + base = 1 nucleotide

Four different nucleotides 1.Deoxyribose 2.Phosphate 3.Base - Adenine 1.Deoxyribose 2.Phosphate 3.Base - Thymine 1.Deoxyribose 2.Phosphate 3.Base - Cytosine 1.Deoxyribose 2.Phosphate 3.Base - Guanine

DNA is shaped like a ladder 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.

DNA Structure Summary Video – click here

Fun DNA Facts -DNA is 1/10 th 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!

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 -Humans and Mice – 85% 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