DNA The Structure of DNA

What does the DNA of all these organisms have in common? They all share a universal genetic code.

Chemical Basis of Life The “code” is unique in every living organism. All organisms have a genetic code (Bacteria, Protists, Fungi, Plants and Animals) Genetic code- determines all inherited characteristics, like a blueprint

Gregor Mendel Gregor Mendel determined that traits were passed from generation to generation. But, I haven’t figured out how this happens

What was this substance called? DNA Deoxyribonucleic Acid

Oswald Avery Avery’s team determined that genes are composed of DNA A gene is a little section of a chromosome – So we have 46 chromosomes all made up of many genes which are made of DNA

Erwin Chargaff Chargaff discovered that DNA has the same amount of adenosine as thymine and the same amount of cytosine as guanine. A = T and G = C AA A A A A A T T T T T T T C CCCC GG G

Rosalind Franklin & Maurice Wilkins Franklin and Wilkins used x-ray to discover that DNA was a double helix.

Hershey & Chase They confirmed that DNA is genetic material By studying viruses, They figured out DNA was genetic material, not a protein

Watson and Crick Watson & Crick won a Nobel Prize for discovering the structural model of DNA. (Double Helix) They credited Wilkins and Franklin. Wilkins also got a Nobel Prize but Franklin did not. Rosalind had passed away and the Nobels are not awarded posthumously.

DNA is a Nucleic Acid Nucleic acids are one of the major organic compounds.

What is a Nucleic Acid? Nucleic acids contain C, H, N, O, P Are made up of nucleotide monomers Store genetic information Help make proteins Examples: DNA & RNA sugar phosphate nitrogen base DeoxyriboNucleic Acid

DNA Structure phosphate nucleotide N base PO 4 Sugar PO 4 N base The numbers are the positions of the carbons on the sugar. (the 3’ end) (the 5’ end) sugar nitrogen base

A NUCLEOTIDE H H2H2 H H H3H3 H H H H H O O O CC C N N P O O O C C C C C O O O C C Phosphate Group 2. 5-Carbon Sugar (Dexoyribose or Ribose) 3. Nitrogen Base Nucleotides, too

Nucleotides There are four nitrogen bases making up four different nucleotides. Adenine Guanine Thymine Cytosine Pyrimidines Purines A C G T N base

Chargaff’s Base Pair Rules Adenine always bonds with thymine. Adenine (A) to Thymine (T) Guanine always bonds with Cytosine. Guanine (G) to Cytosine (C) The lines between the bases represent hydrogen bonds A C G T

3’End 5’End DNA DOUBLE HELIX ladder shaped molecule

Purpose of DNA Why do we have DNA? DNA contains our genetic codes For what does it code? for proteins What actually makes you look the way you do - DNA or Proteins?

Discuss & answer w/Partner What does DNA stand for? What is the shape of DNA? What is the monomers of DNA? What are the 3 parts of a nucleotide? Adenine pairs with ___________ Guanine pairs with ___________

DNA Replication Every single cell in our bodies has the same exact DNA as the original cell we started from. How… That cell is long gone? DNA replication!! – DNA can make an exact copy of itself. DNA is always inside the nucleus of each cell Summary: 1DNA  2 identical DNA

DNA Replication Def: Process where DNA makes an exact copy of itself to pass along to new cells

Steps of DNA Replication 1. DNA unwinds 2. Enzyme (helicase) breaks the bonds between the A, T, C, Gs 3. Extra A,T,C,Gs pair up with unmatched sides by enzyme (DNA polymerase) 4. End product is 2 strands identical to each other and exactly the same as the original