73) What mechanism can introduce new genetic information into a species?

74) Individuals who have a disease such as melanoma do not necessarily have offspring with melanoma. However, individuals with Huntington disease often do pass it on to their offspring. What accounts for the difference in the heritability of the two diseases?

Refer to the figure below, and then answer the question that follows.

75) A G-C base pair holds the double helix together more strongly than an A-T base pair. Can you suggest a reason why?

Refer to the figure below, and then answer the question that follows.

76) A mistake is made during DNA replication, so there is incorrect base pairing in the DNA. Depending on how the replication repair mechanism fixes this problem, a point mutation may or may not result. What might the replication repair mechanism do, and would it result in a point mutation?

A) The repair mechanism might replace the T with a C, which would result in a point mutation.

B) The repair mechanism might replace the G with an A, which would result in a point mutation.

C) The repair mechanism might replace the G with a C, which would result in a point mutation.

D) The repair mechanism might replace the T with a G, which would not result in a point mutation.