Gene Mutations and Chromosomal Aberrations

Which of the following best defines a gene mutation?

• A change in the chromosome number

• A permanent alteration in the DNA sequence of a gene

• A change in the structure of the nucleus

• A mutation that affects an entire organ

What is aneuploidy?

• A condition where an organism has one or more extra or missing chromosomes

• The loss of a portion of a chromosome

• The doubling of an entire set of chromosomes

• The formation of an abnormal chromosomal structure

Which of the following is an example of a chromosomal aberration?

• 
• 
• 
• 

Which one is not the effect due to a change in a single nucleotide in the DNA sequence?

• Missense mutation

• Nonsense mutation

• Silent mutation

• Frameshift mutation

Which of the following is an effect of a missense mutation?

• A change in the amino acid sequence of a protein

• Premature termination of the protein

• Duplication of a portion of a chromosome

• Complete deletion of a gene

Which of the following conditions is most likely caused by a trisomy in chromosome 21?

• Turner syndrome

• Klinefelter syndrome

• Down syndrome

• Trisomy X syndrome

Which of the following statements about polyploidy is/are correct?

• Polyploidy is common in plants but rare in animals.

• Polyploid organisms have multiple sets of chromosomes.

• Polyploidy is often associated with increased size and vigor in plants.

If a point mutation changes a codon from UUU to UAA, which of the following effects would occur?

• Silent mutation with no effect on the protein

• Missense mutation changing one amino acid

• Nonsense mutation causing premature termination

• Frameshift mutation altering the reading frame

Which of the following scenarios would most likely occur if a chromosome underwent an inversion mutation?

• I only

• I and II only

• II and III only

• I, II, and III

Which of the following statements about sickle cell anemia is/are correct?

• I only

• I and II only

• II and III only

• I, II, and III