22 Computer Simulation of DNA Replication and Expression (continued)

Genetic Code
  1. INTRODUCTION TO MUTATIONS

    A mutation in this DNA sequence
    ATA CTG AGT CTT CAC yields this new sequence:
    ATA CTG ATT CTT CAC.

    1. What type of mutation occurred?
      1. Point
      2. Addition
      3. Deletion
      (Answer: A)

    2. How did the mutation affect the amino acid sequence?
      1. Missense - the substitution of one amino acid for another
      2. A large alteration of the amino acid sequence
      3. Nonsense - premature termination of the amino acid sequence
      4. No change - a base change that does not affect the amino acid sequence
      (Answer: C. The mutated DNA sequence ATT transcribes to the triplet UAA on the mRNA, which is a STOP codon.)

  2. PROMOTERS AND PROTEIN FOLD STRUCTURE

    The amino acids of a protein are linked together by a process called dehydration synthesis. The acid group of one amino acid bonds to the amino group of the next, forming a peptide bond and releasing a molecule of water.

    Wool is a protein with alpha helix secondary structure, giving it flexibility and elasticity.

    Silk is a protein fiber with beta sheet secondary structure, containing at least four amino acids linked together by hydrogen bonds.

    A beta bend allows an amino acid chain to reverse direction by folding back on itself, producing a hairpin turn.

    Some amino acid sequences in a protein do not have a structure and take on a random form.

  3. MUTATIONS AND PROTEIN FOLD SIMULATION

    Choose one of these genes:

    • Short Gene- Somatostatin
    • Long Gene - Glucagon
    • Custom Gene - Enter up to 105 bases

    Perform each of these mutations: (within the promoter TATAATG, or 25-30 bases after the promoter)

    • Point
    • Addition
    • Deletion

Lab notes made Jul 12, 2010 by Peter Chen