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DNA & RNA

DNA & RNA. THEIR ROLE IN PROTEIN SYNTHESIS. DNA – BASIC STRUCTURE. Polymer of nucleotides Deoxyribose (5 carbon sugar) Phosphate group Nitrogen base Adenine Guanine Thymine Cytosine Hydrogen bonds Double helix - two strands twisted. DNA – BASIC STRUCTURE.

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DNA & RNA

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  1. DNA & RNA THEIR ROLE IN PROTEIN SYNTHESIS

  2. DNA – BASIC STRUCTURE • Polymer of nucleotides • Deoxyribose (5 carbon sugar) • Phosphate group • Nitrogen base • Adenine • Guanine • Thymine • Cytosine • Hydrogen bonds • Double helix - two strands twisted

  3. DNA – BASIC STRUCTURE • Sides – alternating sugar & phosphate grps • 5’ end • phosphate • 3’ end • sugar • Steps – base pairs • Adenine – Thymine • Cytosine – Guanine • Connected by H-bonds

  4. DNASTRUCTURE & FUNCTION • Blue prints for life • Carries an organisms genetic code • Carries instructions for making proteins: • Immunology • Metabolism • Respiration • Energy/Storage • Found in nucleus of cell

  5. DNA - REPLICATION • Make a copy of DNA • Occur prior to cell division • Steps: • Enzyme DNA polymerase unzips DNA • Two new “complimentary” strands built

  6. RNA – BASIC STRUCTURE • Single strand • Sugar – ribose • Phosphate grp • Uracil replaces Thymine • 3 Types • Messenger (mRNA) • Ribosomal (rRNA) • Transfer (tRNA)

  7. TRANSCRIPTION • Process used to make mRNA from DNA • Occurs in nucleus • RNA polymerase • Enzyme splits DNA so RNA can form • Role of mRNA • Carries directions making protein to the ribosome

  8. TRANSCRIPTION • Promoter • Section DNA where enzyme attaches • TATA Box • Repeating sequence bases – signals where transcription should begin • Immediately followed by start codon AUG

  9. TRANSCRIPTION • CODONS – • Groups 3 bases code for an amino acid • AUG – “start” codon, codes for methianine • 64 different “3-letter” codes for 20 different amino acids • Terminator – stop signals • UGA, UAA, UAG

  10. TRANSLATION • Assembly of amino acids at the ribosome to produce a protein • Initiation – joining of mRNA, tRNA & ribosome

  11. TRANSLATION • Elongation – the joining of amino acids • tRNA bring A. acids to ribosomes • Anticodons on tRNA match to codons on mRNA • Termination – production A. acid stops – no tRNA to match STOP codon

  12. PROTEIN SYNTHESIS

  13. PROTEIN SYNTHESIS • DNA TAC GCT AAG ACT • MRNA • A. ACIDS • TRNA

  14. POINT MUTATIONS • Single base is changed – change in 1 a. acid • Silent (no change A.Acid) or result in disease

  15. FRAMESHIFT MUTATION • Insertion • Addition of base • Deletion • Removal of base • Both types result in change of entire amino acid sequence • Cytosine insertion on chrom. 16 believed cause Crohn’s disease

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