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What ’ s the Purpose of All This DNA Stuff?

What ’ s the Purpose of All This DNA Stuff?. *Sequence of nitrogen bases along the DNA strand (genes) code for an amino acid sequence (which make up proteins) - Proteins are responsible for the traits organisms possess. Mutations. A change in the genetic information. Kinds of Mutations.

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What ’ s the Purpose of All This DNA Stuff?

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  1. What’s the Purpose of All This DNA Stuff? *Sequence of nitrogen bases along the DNA strand (genes) code for an amino acid sequence (which make up proteins) - Proteins are responsible for the traits organisms possess.

  2. Mutations • A change in the genetic information

  3. Kinds of Mutations Point mutation: gene mutation involving a change in 1 or a few nucleotides Substitutions = 1 base is changed for another Ex: G toC or A to G insertions = 1 base is inserted in the sequence CGTACT - CGTAACT

  4. deletion = 1 base is deleted from the sequence • CGTACT - CTACT • Substitutions will usually only affect 1 amino acid • Insertions or deletions will change the reading frame of mRNA (how we decipher the mRNA into AA’s)

  5. Frameshift mutation: mutations that shift the reading frame of the genetic message - Will change the amino acid sequence of every AA that follows the mutation = protein probably won’t function correctly Insertion and deletion

  6. Significance of Mutations • Some mutations do not have any affect (silent mutation) • some change function of proteins produced; changing biological activities of an organism • some are beneficial and help an organism survive in a changing environment

  7. Mutations in body cells won’t be passed on to offspring • mutations in gametes will Polyploidy: condition in which an organism has extra sets of chromosomes - Can make some organisms stronger & larger

  8. Chromosomal Mutations 4 Types: • Deletion = loss of part or all of a chromosome • Duplication = produce extra copies of parts of a chromosome • Inversion = reverse the direction of parts of a chromosome

  9. 4. Translocation = part of a chromosome breaks off and reattaches to another

  10. Assignment: Work together with a partner (or by yourself) and analyze the DNA strands on the handout. You will decided what kind of mutation has occurred.

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