CHALLENGE QUESTION ANSWERS
- Question: How many cells in the eight-celled Slooze worm will have mutations
if the DNA repair enzymes change the G-T base pair back to a G-C base pair before
the third cell division? Assume that the G looks normal to the cell after repair occurs.
Answer: None of the cells will have the mutation. The mutation was fixed before
the next cell division occurred, so the mutation was not passed to the next
generation of cells.
Question: How many Slooze worm cells will be mutated if the DNA repair enzyme
only corrects the G-T mismatch to G-C after the third cell division?
Answer: One cell will be mutated. It will carry the A-T mutation.
Question: How many cells in the Slooze worm will be mutated if the DNA repair
enzyme changes the G-T to an A-T before the third cell division? (The enzyme
might do this if it treats A-T as the correct nucleotide base pair and fixes the G.)
Answer: Two cells will be mutated. They will both carry the A-T mutation.