11.1 Genes are made of DNA. Griffith Experiment Avery Experiment -Destroyed proteins -Mice still died with mix

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11.1 Genes are made of DNA Slide 2 Griffith Experiment Slide 3 Avery Experiment -Destroyed proteins -Mice still died with mix Slide 4 Hershey Chase Experiement Virus- nucleic acid wrapped in protein; needs host to reproduce Bacteriophage- virus that infects bacteria Slide 5 Hershey Chase Experiment Slide 6 Question 1 & 2 1.Explain how experiments done by Griffith, Avery & Hershey and Chase supported that genes are made of DNA? [4 points] 2. Identify the parts of DNA and how the double helix is put together (bases)? [4 points] Slide 7 11.2 Nucleic acids store information in their sequences of chemical units Slide 8 DNA into chromosomes Slide 9 Nitrogenous Bases Slide 10 DNA- structures Slide 11 DNA Nucleotide Slide 12 Rosalind Franklin & Maurice Wilkins 1950s photographs of the DNA molecule using X-ray crystallography which showed the shape to be a helix Slide 13 Erwin Chargaff 1951, proved that the % of A = T and % of G = C Slide 14 Watson &Crick 1953, used data from the other scientists and built models to finally figure out the exact structure of DNA 1962 won the nobel prize in Medicine Slide 15 11.3 DNA replication is the molecular mechanism of inheritance Slide 16 DNA Replication Slide 17 Enzymes are protein molecules that catalyze chemical reactions in a cell usually any protein ending in ase is an enzyme Helicase- unwinds DNA DNA Polymerase 3 ( ) - Adds complementary nucleotide DNA Polymerase 1 ( )- Checks for error Single strand bind proteins- help hold open DNA Slide 18 DNA Replication DNA primase- makes an initiation (starting) site for replication RNA primer- short segment of RNA where DNA replication starts DNA ligase- binds two nucleotides together Topoisomerase (gyrase)- relaxes and recoils helix Slide 19 DNA Replication Slide 20 11.4 A gene provides the information for making a specific protein Slide 21 DNA & RNA Deoxyribose sugar A,T,C,G Double strand Stays in Nucleus DNA Ribose sugar A,U,C,G Uracil pairs with adenine Single strand Nucleus to cytoplasm Messenger (mRNA), transfer (tRNA), ribosomal (rRNA) Slide 22 Types of RNA mRNA - Messenger RNA: Encodes amino acid sequence of a polypeptide. tRNA - Transfer RNA: Brings amino acids to ribosomes during translation. rRNA - Ribosomal RNA: With ribosomal proteins, makes up the ribosomes, the organelles that translate the mRNA. snRNA - Small nuclear RNA: With proteins, forms complexes that are used in RNA processing in eukaryotes. (Not found in prokaryotes.) Slide 23 DNA & RNA Slide 24 Beadle and Tatum Beadle and Tatum discovered when looking at mutant Neurospora crassa (bread mold) Individual gene produces a specific enzyme One gene - one polypeptide (combinaiton of amino acids) Slide 25 DNA to Protein Slide 26 Table of Codons Slide 27 11.5 There are two main steps from genes to proteins Slide 28 Transcription: Base Pairing of mRNA with DNA Slide 29 RNA Transcription Slide 30 Steps of Transcription 1. DNA double helix unwound and separated by RNA polymerase 2. RNA polymerase adds RNA nucleotides together, making a single strand of mRNA which is complementary to 1 strand of the DNA Slide 31 Steps of Transcription 3. mRNA is processed (modified) before leaving the nucleus a.introns (non coding regions) are cut out of the mRNA b.exons (coding regions) are spliced together to form the final mRNA product 4. Introns are cut out and exons are spliced together to form the final copy of messenger RNA (mRNA) Slide 32 RNA editing Slide 33 Most eukaryotic protein-coding genes contain segments called introns, which break up the amino acid coding sequence into segments called exons. The transcript of these genes is the pre-mRNA (precursor-mRNA). The pre-mRNA is processed in the nucleus to remove the introns and splice the exons together into a translatable mRNA. That mRNA exits the nucleus and is translated in the cytoplasm. Slide 34 Transfer RNA (tRNA) Slide 35 Adding Amino Acids to a Polypeptide Chain Slide 36 Initiation Translation Slide 37 Elongation Translation Slide 38 Termination Translation Slide 39 Steps of Translation 1. mRNA leaves the nucleus and is transported to the ribosome where translation takes place 2. Ribosome holds onto the mRNA, the mRNA codon AUG is located in the P site of the ribosome 3. tRNA carries an amino acid to the P site of the ribosome 4. Another tRNA carries the next amino acid to the A site of the ribosome Slide 40 Steps of Translation 5. Two amino acids are joined together with a peptide bond 6. tRNA in the P site leaves 7. Ribosome moves along the mRNA until the next codon is located in the A site (the tRNA which was located in the A site is now in the P site and is holding the peptide chain) 8.tRNA carries the next amino acid to the A site Slide 41 Steps of Translation 9.New amino acid is joined to the peptide chain (the polypeptide is made of 3 amino acids) 10.tRNA in the P site leaves 11.Process continues until a stop codon appears in the A site of the ribosome 12. Polypeptide is now complete Slide 42 Rules for translation 1. Codon is a three-base word that codes for one amino acid 2. Determine the amino acid coded for by an mRNA codon use the genetic code 3. Genetic code is universal all species use the same genetic code, the same 20 amino acids are used in all living organisms Slide 43 Summary of Translation Process Slide 44 11.6 Mutations can change the meaning of genes Slide 45 Point vs. Frameshift Mutations Slide 46 Chromosome Mutations Slide 47 How mutations affect genes 1. A mutation is any change in the nucleotide sequence of DNA. 2.Two categories of mutations a.Base substitutions (point) replacement of one nucleotide with another i.This can change the protein or not change the protein b.Base insertions or base deletions (frameshift) addition of an extra nucleotide or subtracting a nucleotide i. Have more effect on the protein than a substitution Slide 48 What causes mutations? 1. Mistakes during DNA replication can cause mutations 2. Mutagens physical or chemical agents that cause mutations a. Physical mutagens high energy radiation, X- rays, Ultraviolet light b. Chemical mutagens chemicals that are similar to DNA bases and cause incorrect base- pairing Slide 49 Mutations Effects Body Cells Cancers Gametes Birth defects Genetic disorders Slide 50 Ch. 11 Test Vocabulary DNA & RNA structure Replication, transcription, translation- content and problems Scientists & experiments involved Mutations & mutagens- types and effects