Mutations and Gene Regulation

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Mutations and Gene Regulation

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Slide Content
  1. Mutations and Gene Regulation

    Slide 1 - Mutations and Gene Regulation

  2. Review of Genetic Code

    Slide 2 - Review of Genetic Code

    • Genes are the instructions for making specific proteins.
    • Genes are made of DNA.
    • A single strand of DNA contains hundreds of genes.
    • Humans have 46 pieces of DNA in each cell, and 20,000-25,000 genes (still figuring that out!)
  3. DNA and the Genetic Code

    Slide 3 - DNA and the Genetic Code

  4. Examples of Human Genes

    Slide 4 - Examples of Human Genes

    • 1
    • 2
    • Hemoglobin
    • 3
    • BRCA-1
    • Lactase Enzyme
  5. Lactase Enzyme

    Slide 5 - Lactase Enzyme

  6. GENE 1- Lactase Enzyme

    Slide 6 - GENE 1- Lactase Enzyme

    • DNA Sequence 1: --CCC-CTG-GGC-
    • RNA Sequence 1: --GGG-GAC-CCG
    • Protein 1: -GLYCINE-ASPARTIC ACID-PROLINE
    • Variation 1: Lactose Intolertant (cannot digest)
    • DNA Sequence 2: -TCC-CTG-GGC
    • RNA Sequence 2: -AGG-GAC-CCG
    • Protein 2: -ARGININE-ASPARTIC ACID-PROLINE
    • Variation 2: Lactose Tolerant (can digest)
  7. Gene 2- Hemoglobin Protein

    Slide 7 - Gene 2- Hemoglobin Protein

  8. Hemoglobin Gene

    Slide 8 - Hemoglobin Gene

    • Sequence 1: --GGA-CTC-CTC-
    • Protein 1: -PRO-GLT-GLT-
    • Variation 1: Normal Hemoglobin
    • Sequence 2: --GGA-CAC-CTC-
    • Protein 2: -PRO-VAL-GLT-
    • Variation 2: Abnormal Hemoglobin = SICKLE CELL
  9. BRCA-1 and Cancer

    Slide 9 - BRCA-1 and Cancer

  10. Change in Sequence, Change in Trait?

    Slide 10 - Change in Sequence, Change in Trait?

    • Changing the DNA sequence does not necessarily change the form of the trait
    • There is ONLY a problem if the PROTEIN is affected (amino acid sequence gets changed)
    • Ex: CTT  CTC
    • CODONS: GAA  GAG
    • Amino Acids = GLT = GLT
    • = NOT A PROBLEM!!!
  11. MUTATIONS

    Slide 11 - MUTATIONS

    • A mutation is any change in the DNA.
    • Some mutations are silent (do not change the protein)
    • Mutations may be harmful if they change the amino acid sequence.
    • Examples of Mutations:
    • Substitution-
    • GAG  GAC
    • Insertion-
    • GAATC  GAAATC
    • Deletion-
    • GAATC  GATC
  12. What CAUSES Mutations?

    Slide 12 - What CAUSES Mutations?

    • Many / most mutations are RANDOM
    • Errors during replication (copying DNA)
    • Some mutations are caused by mutagens = any substance that causes a change to DNA
    • Radiation (X-rays, UV rays)
    • Chemicals (many carcinogens are mutagens)
  13. Gene Regulation

    Slide 13 - Gene Regulation

    • In any individual cell, only a small fraction of the total genes are working; most of the genes are silent.
    • How does a cell “know” whether to turn a gene “on” or “off”?
    • Certain triggers cause genes to turn “on” (start making protein) or turn “off” (stop making protein)
    • Macrophage, Skin Cells
    • Rods and Cones
  14. Gene Activation: Genes Turned “on” or “off”

    Slide 14 - Gene Activation: Genes Turned “on” or “off”