Your “Do Now”2/17 Get out your KWL Take a ½ sheet of paper Write down 2 things that another person had on their KWL’s “L” column Be ready to share out in 5 minutes! 1

Agenda2/16 CH 12 DNA Notes 1 Practice activity Exit Slip 2

Reminders CH 11 Test Quiz 3 Retakes Study guides turned in Notebooks turned in 3

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CH 12 Notes #1 DNA Basics DNA = Deoxyribonucleic Acid 5

Where is DNA found? Found in the nucleus of every cell Remember: chromosomes are made of DNA 6

7 DNA DNA.DNA is often called the blueprint of life. DNA contains the instructions for making all living things.

8 DNA’s structure was first described in 1953 by James Watson, Francis Crick And Rosalind Franklin

9 4 Reasons why we study DNA We study DNA for many reasons 1.Learn how living things work 2.Medical benefits such as cures for diseases, 3.Better food crops 4.Solving crimes

10 The Shape of DNA The basic shape is like a twisted ladder. This is called a double helix.

Check for understanding Who discovered DNA and when? What’s the shape of DNA called? Where is DNA found? What’s one reason we study DNA? Why is it called the blueprint of life? What does it stand for? 11

Get out your KWL Add 1 thing to the “Learned” column Turn it in! 12

Untwisted Twisted (double helix)

Chemicals in DNA 14 There are 4 chemicals in DNA We call them Nitrogenous bases

15 The 4 Nitrogenous Bases Cytosine C Thymine T Adenine A Guanine G

Chemicals in DNA 16 There are 4 chemicals in DNA We call them Nitrogenous bases

17 Base-pairing rule: each base will only pair with one other base A – TC - G

The 4 bases are attached to a Sugar-phosphate backbone 18

19 Phosphate + Sugar + Base = Nucleotide

Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G) Section 12-1 Go to Section: The nucleotides are held together by hydrogen bonds

The number and order of the base pairs tells our cells how to function. Each species has its own unique DNA sequence (order of A,T,C,G) 21

Genetic Diversity… The order of bases makes each living thing different BUT, closely related species share more of their DNA –ATTCGATCA –ATTCGATTA

23 Another human? 99.9% - All humans have the same genes, but some of these genes contain sequence differences that make each person unique. A chimpanzee? 98% - Chimpanzees are the closest living species to humans. A mouse? 92% - All mammals are quite similar genetically. A fruit fly? 60% - Studies of fruit flies have shown how shared genes govern the growth and structure of both insects and mammals. Yeast? 26% - Yeasts are single-celled organisms, but they have many housekeeping genes that are the same as the genes in humans, such as those that enable energy to be derived from the breakdown of sugars. A weed (thale cress)? 18% - Plants have many metabolic differences from humans. For example, they use sunlight to convert carbon dioxide gas to sugars. But they also have similarities in their housekeeping genes. What percent of their DNA matches yours? Why?

Example Problem 24 A T C G A T G G C A C A T T T A G C T A C C G T G T A A

25 DNA by the Numbers Each cell has about 2 meters of DNA. The average human has 75 trillion cells. The average human has enough DNA to go from the earth to the sun more than 400 times. DNA has a diameter of only m. The earth is 93 million miles from the sun.

Other cool DNA Info Genetic barcoding –Take a sample of any living thing & find out what it is! Genetic engineering –Change the genetic code of an organism to alter its traits 26

DNA Practice Problems Prob #3: The order makes traits Work on these on your own –Due at the end of the hour Add 1 thing to your KWL & turn it in 27

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