Question

1. a dna segment originally reads tac gaa cta. after replication, it reads tac gga cta. which type of mutation occurred, and what is its likely effect? a. substitution; may or may not change one amino acid b. deletion; since it will cause a frameshift mutation c. insertion; may or may not cause a nonsense mutation d. duplication; since it will result in no change to the protein 6. which environmental factor is most likely to cause a heritable mutation? a. high sugar diet; because it can cause weight gain b. radiation exposure; because it can directly change the dna in gametes c. exercise; because it can break down muscle fibers d. lack of sleep; because it can result in a loss of brain function

Explanation:

For question 5:

• In the DNA segment, the original 'GAA' changed to 'GGA'. This is a substitution mutation (one base is replaced by another).
• Substitution mutations may or may not change the amino - acid because of the degeneracy of the genetic code (multiple codons can code for the same amino - acid).

For question 6:

• Heritable mutations are those that occur in gametes (sperm and eggs).
• Radiation exposure can directly damage the DNA in gametes. A high - sugar diet, exercise, and lack of sleep do not directly change the DNA in gametes in a way that would lead to heritable mutations.

Answer:

1. A. Substitution; may or may not change one amino acid
2. B. Radiation exposure; because it can directly change the DNA in gametes