7a. DNA and DNA Replication Living Environment Mr. Wiley 144

Key players in discovering DNA Found by Friederich Miescher James Watson and Francis Crick Maurice Wilkins Rosalind Franklin

I. What is DNA? DNA  Deoxyribonucelic Acid The genetic information (instructions) for all life Three Important Jobs/Characteristics Determine the traits of an organism Able to be copied easily Carry information from one generation to the next

II. DNA Structure DNA has 2 strands (Double Stranded) Strands bind together with hydrogen bonds Looks like a ladder Ladder twists forming a double helix (shape of DNA)

II. DNA Structure Double Stranded  Ladder Double Helix

II. DNA Structure Base unit/subunit: Nucleotides Each nucleotide contains 3 parts: Phosphate group Deoxyribose (sugar) Nitrogen Base Phosphate Group Deoxyribose (Sugar) Nitrogen Base Phosphate Group and Sugar are the “backbone” of DNA

There are 4 different nitrogen bases that help to make DNA molecules: Adenine or “A” Thymine or “T” Guanine or “G” Cytosine or “C” II. DNA Structure A T C G

What are these called and what do they do for you? Bind- to attach II. DNA Structure

There are 4 different nucleotides that help to make DNA molecules: Chemicals can bind (or attach) to each other Adenine or “A” Thymine or “T” Guanine or “G” Cytosine or “C” II. DNA Structure A T C G

Base pairing “A” binds with “T” “G” binds with “C” II. DNA Structure A T C G

III. DNA Replication Replicate- 1.Helicase “unzips” DNA 2.DNA Polymerase makes new copies of strands. HELICASE DNA Polymerase Make copies 1 Strand of DNA 2 Strands of DNA

IV. Base Pairing Practice A-T-T-G-C-C-C-T ______________ A-A-C-A-A-G-T-C ______________ T-G-G-G-C-G-C-G ________________ T-A-T-T-C-C-C-G _____________ T-G-C-A-C-A-T-G ______________ T-T-G-T-C-T-G-G ______________