Chapter 12.3 dna,rna and protein


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Chapter 12.3 dna,rna and protein

  1. 1. 12.3 DNA, RNA, & Protein
  2. 2. <ul><li>Chain of events: </li></ul><ul><li>DNA -> RNA-> Synthesis of Protein </li></ul><ul><li>Occurs in ALL living things – from bacteria to humans </li></ul>
  3. 3. RNA – Ribonucleic Acid <ul><li>Single stranded helix </li></ul><ul><li>Contains ribose sugar (not deoxyribose) </li></ul><ul><li>Uracil replaces thymine </li></ul><ul><li>3 types of RNA </li></ul><ul><li>1. mRNA (messenger RNA) </li></ul><ul><li>2. rRNA (ribosomal RNA) </li></ul><ul><li>3. tRNA (transfer RNA) </li></ul>
  4. 4. Messenger RNA (mRNA) <ul><li>Carries genetic information from DNA </li></ul><ul><li>Travel from nucleus to the ribosome </li></ul><ul><li>Direct protein synthesis </li></ul><ul><li>Ribosomal RNA (rRNA) </li></ul><ul><li>Helps join the mRNA codons to the tRNA anticodons in the ribosome s. It produce enzymes needed to bond amino acids together during protein synthesis </li></ul><ul><li>Transfer RNA (tRNA) </li></ul><ul><li>Transport amino acids to the ribosome </li></ul>
  5. 5. <ul><li>Transcription- The process of transferring genetic information from DNA to RNA </li></ul><ul><li>forms one single-stranded RNA molecule </li></ul>
  6. 6. Steps of Transcription <ul><li>Step 1: DNA molecule unzips. RNA polymerase binds where mRNA will be synthesized. </li></ul><ul><li>Step 2: Free RNA nucleotides attach to DNA nucleotides by base pairing </li></ul><ul><li>Step 3: mRNA strand breaks from DNA </li></ul><ul><li>Step 4: mRNA leaves nucleus and goes to cytoplasm to the ribosomes </li></ul>
  7. 7. Transcription Clip
  8. 8. <ul><li>Codon- 3 base code in DNA or mRNA. Each base of a codon in DNA is transcribed in to the mRNA code. </li></ul>
  9. 9. <ul><li>The order of nitrogen bases in mRNA will determine the type and order of amino acids in a protein </li></ul><ul><li>The code is universal - the codons represent the same amino acids in all organisms </li></ul><ul><li>Three nucleotides code for one amino acid </li></ul><ul><li>Example – UUU codes for phenylalanine </li></ul>
  10. 10. Codons <ul><li>64 possible codons </li></ul><ul><li>20 different amino acids </li></ul>
  11. 11. Codons <ul><li>Start Codon </li></ul><ul><li>AUG </li></ul><ul><li>Stop Codons </li></ul><ul><li>UGA </li></ul><ul><li>UAA </li></ul><ul><li>UAG </li></ul>
  12. 12. <ul><li>Translation- the process of converting the information in mRNA into amino </li></ul><ul><li>acid chains (proteins) </li></ul><ul><li>It occurs at the ribosome in the cytoplasm </li></ul><ul><li>tRNA - brings amino acids to the ribosomes </li></ul><ul><li>Each mRNA codon joins to the correct tRNA anticodon (complement to the mRNA codon) </li></ul><ul><li>the end result of translation is the formation of an amino acid chain (protein) </li></ul>
  13. 14. Steps of Translation <ul><li>Step 1: tRNA picks up amino acids in cytoplasm and takes to mRNA attached to the ribosome </li></ul><ul><li>Step 2: The anticodon on the tRNA connects to the complementary codon on the mRNA strand </li></ul><ul><li>Step 3: The amino acids attach to one another by peptide bonds forming long chains </li></ul><ul><li>Step 4: When stop codon is reached, translation ends and amino acid strand released </li></ul>
  14. 15. Nitrogen Base Sequence
  15. 17. Quick Molecular Genetic Terminology <ul><li>Replication = DNA  DNA </li></ul><ul><li>Transcription = DNA  RNA </li></ul><ul><li>Translation = RNA  Amino Acids </li></ul><ul><li>Polypeptide = Chain of amino acids </li></ul><ul><li>Adenine, cytosine, & guanine = DNA & RNA </li></ul><ul><li>Thymine = DNA Only </li></ul><ul><li>Uracil = RNA Only </li></ul>
  16. 18. Transcription/Translation Clip
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