| Activity #4: Gene Mutations
Text: pg. 252-255 Sometimes the nitrogen base sequencing in a DNA strand changes. When this happens, protein synthesis goes awry. 1) What is a point mutation? How do they affect protein synthesis? 2) What are INSERTIONS and DELETIONS? How do they affect protein synthesis? NOTES: Luckily, gene mutations are often caught and then not used in protein synthesis AND more than one codon gives rise to the same amino acid so the correct protein is still made in some cases with the mutations AND remember that if gene mutations occur in areas of pre-mRNA that is cut out (INTRONS) then these mutations won�t affect the proteins that are made. Still, gene mutation can cause proteins that are different and thus would lose their original functionality. 3) What are several causes of gene mutations? Briefly explain how each work to mutate your genes. a) Naturally occurring b) Ionizing radiation (exposure of x-rays over a period of time) c) Nonionizing radiation (UV light) d) Chemicals/ Carcinogens 4) BUT can a gene mutation produce POSITIVE effects? You bet! Let me quote from our text, �A protein that is specified by a heritable mutation may have harmful, neutral, or beneficial effects on the individual�s ability to function in the prevailing environment.� Since naturally occurring mutations don�t happen very often (0.0001 to 0.000001 per gene per generation) it would take a LONG, LONG time to see products of any gene mutation let alone products of gene mutation that�s been passes down from generation to generation. We call this EVOLUTION. 5) Explain how moths �evolve� from one color to another in the post-industrial world. Activity #5: Review Questions Answer in complete sentences please. Pg. 255 assessment questions #1-5 |