41) What is the benefit of mutations?

A) They eliminate unneeded regions of chromosomes.

B) They increase the shuffling of existing genetic information.

C) They create cancerous cells, which grow faster than others.

D) They add new genetic information upon which evolution can act.

42) What is the cause of Huntington disease?

A) a somatic cell mutation that causes cells to proliferate without control

B) a mutation that results in defective DNA polymerase

C) loss of the chromosome with the gene for a blood protein

D) a mutation in which there are repeating groups of three nucleotides

E) a mutation that results in defective amino acid synthesis

43) What happens if an incorrect nucleotide is not removed and replaced by the cell’s DNA-correcting machinery?

A) A point mutation has occurred.

B) The result is a chromosomal aberration.

C) The effect will be lethal, and the cell will die.

D) The cell will become cancerous.

E) The entire chromosome must be destroyed.

44) What is the difference between whole-chromosome aberrations and point mutations?

A) Point mutations are not permanent changes in the DNA; aberrations are permanent.

B) Aberrations are not permanent changes in the DNA; point mutations are permanent.

C) Point mutations are the loss of parts of chromosomes; aberrations are the loss of whole chromosomes.

D) Point mutations affect a single base pair in the genome; aberrations affect a large section.

45) What is the relationship between mutations and cancer?

A) Cells do not require mutations to become cancerous but acquire them as they divide.

B) Cells lose the ability to mutate their DNA and evolve once they become cancerous.

C) Some mutations cause cells to lose control over cell division, resulting in cancer.

D) Any point mutation will cause a cell to start proliferating without control, resulting in cancer.

E) Only a mutation can stop a cell once it becomes cancerous.

46) What is one mechanism by which a mutation can cause melanoma?

A) by causing the accumulation of Huntington protein in melanocytes, which keeps them moving through the cell cycle

B) by causing the accumulation of altered BRAF protein in germ-line cells

C) by the production of an altered BRAF protein that keeps melanocytes moving through the cell cycle

D) by preventing the BRAF protein from being able to repair damaged DNA

47) A trinucleotide repeat refers to:

A) a nucleotide that is made of three subunits: a sugar, a phosphate, and a nitrogenous base.

B) a sequence of three nucleotides that repeats and can be involved in genetic diseases.

C) the same nucleotide repeating three times in a row.

D) a nucleotide that contains three bases.

48) Any agent that can change the base sequence of DNA is known as a:

A) trinucleotide repeat.

B) free radical.

C) cancer.

D) mutagen.

E) spontaneous event.

49) Which of the following would be considered an environmental mutagen?

A) free radicals

B) ultraviolet light

C) spontaneous events

D) the collision of water molecules with DNA

E) DNA replication errors