Deoxyribonucleic Acid

History:

1. Theory of Evolution: 1859; Darwin

2. Science of Genetics: 1870; Mendel

3. Chromosomes Discovered: 1910; T.H. Morgan

4. DNA discovered: 1953; James Watson, Francis Crick and Rosalind Franklyn -used x-ray crystallography to see DNA shape -died at age 38 -used Franklyn’s to write their paper -received the Nobel prize in 1962

DNA Structure -Shaped like a twisted ladder -Called double helix

DNA Structure -Nucleotide: monomer of DNA made of a sugar (deoxyribose), a base and a phosphate

Bases of DNA Purines (large bases): -adenine (A) -guanine (G) Pyrimidines (small bases): -thymine (T) -cytosine (C) *Adenine with thymine *Cytosine with Guanine -bonded with weak hydrogen bonds

How to Draw DNA

Nucleic Acid Processes: 1.Replication: DNA copying and making new DNA 2.Transcription: DNA making RNA 3.Translation: RNA synthesizes proteins

Central Dogma:

DNA Replication -cell divide and must replicate DNA -happens before mitosis 3 Steps: 1.The enzyme helicase moves over DNA and unzips it at the hydrogen bonds 2.DNA polymerase (enzyme) moves along the exposed strand and adds the complimentary nucleotide 3.Two daughter strands are formed

DNA Replication -One mistake for every 10,000 base pairs -Mutation: a change in nucleotide sequence -Not always bad; some good; most neutral

DNA vs. RNA Comparison DNA 1.FX: stores genetic information 2.Double helix structure 3.Base: A, C, G, and T 4.Sugar: deoxyribose RNA 1.FX: synthesizes proteins 2.Single helix structure 3.A,C,G, and Uracil 4.Sugar: ribose

Three Types of RNA 1. Messenger RNA (mRNA): provides the code for amino acids 2.Transfer RNA (tRNA): carries amino acids to ribosome 3.Ribosomal RNA (rRNA): unknown function

Transcription: DNA makes RNA 4 Steps: 1.RNA polymerase opens DNA and adds complimentary RNA nucleotides to the DNA 2.RNA reaches a “stop” sequence 3.mRNA leaves the nucleus to build proteins

Translation: protein synthesis Protein: What are they? -amino acids are the monomers -20 different amino acids -peptide bonds between amino acids -codon: a three base code on mRNA that codes for amino acids -each codon is specific for an amino acid

mRNA Coding Chart

Decode the following strand of DNA in mRNA then into a protein Protein: “START”- Phe – Asn – Ala – Thr – His – “stop” mRNA: AUG UUU AAC GCU ACA CAC UAA DNA: TAC AAA TTG CGA TGT GTG ATT

Translation: Steps 1.mRNA leaves the nucleus, enters cytoplasm, attaches to a ribosome. 2.tRNA attaches to the mRNA with an “anticodon”, carrying an amino acid 3.Amino acid attaches to a ribosome and starts the protein. tRNA leaves to get a new amino acid 4.Ribosome moves down the mRNA picking up a new amino acid at each codon. 5.Reaches the stop codon and ends translation 6.Protein is released for a metabolic process.

DNA Technology

The Genome:

- The totality of DNA base pairs in the cells of a species -exact sequence of DNA bases -All the ACTGs on each chomosome -One of the greatest discoveries of all time

Sequenced Genomes 1.Human 2.Chimpanzee 3.Rice 4.Malaria parasite 5.E. coli 6.Lab mouse 7.Drosophila melanogaster

National Genome Project -Director: Francis Collins -“blue print” of human body: the “holy grail” -12 year project -Fully funded by U.S. Government -Life changing

How it will change our lives: - Gene screening at an early age -Know diseases in advance -Designer drugs -Design babies -Genetic counselors -Lifespan expanded -Genetically modified organisms

Genome is the future of medicine -Pre-treat disease and illness before it manifests itself -Changed our legal system, medical science, understanding evolution

DNA Technology and Criminology

Polymerase Chain Reaction -Process of amplifying a sample of DNA -Uses: criminal convictions, ID human remains, new species, taxonomy, evolution

Gel Electrophoresis: DNA fingerprinting 1.DNA is put into a gel 2.Stained with methyl or violet 3.Moved through gel with electricity 4.Separate by size 5.The more matching bands the more likely a sample and an unknown are related