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Deoxyribonucleic Acid
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History:
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1. Theory of Evolution: 1859; Darwin
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2. Science of Genetics: 1870; Mendel
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3. Chromosomes Discovered: 1910; T.H. Morgan
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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
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DNA Structure -Shaped like a twisted ladder -Called double helix
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DNA Structure -Nucleotide: monomer of DNA made of a sugar (deoxyribose), a base and a phosphate
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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
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How to Draw DNA
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Nucleic Acid Processes: 1.Replication: DNA copying and making new DNA 2.Transcription: DNA making RNA 3.Translation: RNA synthesizes proteins
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Central Dogma:
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Review Complete the following: Transcription: DNA making __________ Translation: RNA making ___________ Replication: DNA making _____________
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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
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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
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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): comprises the ribosome
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Transcription: DNA makes RNA 3 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
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Translation: protein synthesis Protein: -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
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mRNA Coding Chart
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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
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Steps of Translation 1.mRNA attaches to the ribosome 2.tRNA brings the amino acids to the ribosome 3.Protein is built one amino acid/codon at a time 4.Until it reaches a “stop” codon
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Mutations -Mutation: a change in base sequence -Not always bad; some good; most neutral
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Protein Expression 1.True or False: All cells in an individual have the same DNA 2.How are cells in the same individual different? (liver cells, bone cells, skin cells, etc.)
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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.
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DNA Technology
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The Genome:
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- 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
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Sequenced Genomes 1.Human 2.Chimpanzee 3.Rice 4.Malaria parasite 5.E. coli 6.Lab mouse 7.Drosophila melanogaster
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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
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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
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Genome is the future of medicine -Pre-treat disease and illness before it manifests itself -Changed our legal system, medical science, understanding evolution
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DNA Technology and Criminology
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Polymerase Chain Reaction -Process of amplifying a sample of DNA -Uses: criminal convictions, ID human remains, new species, taxonomy, evolution
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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
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