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.
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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.
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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.