Aim: How can we observe DNA? Do Now: Construct a “K-W-L” chart (Know, Want to Know, Learned) about DNA (in your notebook) and complete the first 2 columns.

What is Genetics? The study of Heredity Heredity is the passing of genetic information from one generation to the next

The Human Genome A genome is all of the genes possessed by an organism The human genome consists of over 100,000 genes Each gene has at least 10,000 nucleotide pairs

How alike are we? The human genome contains 3164.7 million chemical nucleotide bases (A, C, T, and G). The average gene consists of 3000 bases, but sizes vary greatly The total number of genes is estimated at 30,000 to 35,000 The order of almost all (99.9%) nucleotide bases are exactly the same in all people. The functions are unknown for over 50% of genes discovered to date.

DNA Structure

DNA DNA resembles a twisted ladder called a double helix. It is made up of subunits called nucleotides. Each subunit or nucleotide contains 3 chemical parts: A sugar, a phosphate, and a nitrogenous base (ATCG)

Base Pairs The four bases found in DNA are Thymine (T) , Adenine (A), Cytosine (C), and Guanine (G) A always bonds with T and G always bonds with C Remember: AT Grand Central Bases are joined by weak hydrogen bonds

DNA Base Pairing Animation

Match up the Base Pairs A G C T T C G A

Extracting DNA From Cells Problem: How can we extract strawberry DNA? Why strawberries? They contain a lot of DNA (octoploid)! Follow the “Delicious DNA Protocol”.

Summary Questions Describe the procedure you followed in this lab in your own words. Write a detailed description of your observations of the strawberry DNA. Why might scientists need to extract DNA from cells? Explain the molecular structure of DNA (use your notes). Why can’t you see this structure in the sample you extracted? Determine how this procedure could be used to extract DNA from human cheek cells.