BIOL 3301 Exam 3 Review Questions 2026/27 Update - UH
1. Holliday junctions can be resolved by different combinations of north-south and east-west
cuts. Two examples are shown below. What type of resolution would result in a gene conversion
at the site of the Holliday junction, but no crossing over?
A. One east-west cut and one north-south cut.
B. Two east-west cuts.
C. Two north-south cuts.
D. Holliday junctions cannot be resolved to produce gene conversion without crossing over.
2. A gene mutates into a dominant disease causing allele in 1 out of every 100,000 gametes. If
you observe 1,000,000 births, how many babies do you expect to be born with the disease?
A. 5 babies
B. 10 baby
C. 20 babies
D. 40 babies
E. 50 babies
3. A dominant lethal allele appears in 1 out of 100,000 gametes. About how many affected
individuals are expected per 100,000 births?
A. 1
B. 2
C. 4
D. 8
BIOL 3301 Exam 3
, 4. Consider the following DNA sequence:
5'-ATGCATGGT-3'
Which of the following sequences is most likely to result from mutation to the sequence above?
A. 5'-ATGATGGT-3'
B. 5'-ATGGCATGGT-3'
C. 5'-ATGGATGGT-3'
D. 5'-ATGAATGGT-3'
E. 5'-ATGTATGGT-3'
5. What is the inbreeding coefficient (F) between an uncle and his niece (shown in the pedigree
below)?
A. (1/2)5 = 0.03125
B. 2(1/2)5 = 0.0625
C. 4(1/2)5 = 0.125
D. 2(1/2)3 = 0.25
E. 2(1/2)2 = 0.5
6. Gene X has two alleles (X1 and X2). X2X2 homozygotes are half as likely to survive from birth
to reproductive age as heterozygotes or X1X1 homozygotes (w11=1.0, w12=1.0, w22=0.5). A
population starts with 50 individuals of each genotype, and they survive with a probability given
BIOL 3301 Exam 3
1. Holliday junctions can be resolved by different combinations of north-south and east-west
cuts. Two examples are shown below. What type of resolution would result in a gene conversion
at the site of the Holliday junction, but no crossing over?
A. One east-west cut and one north-south cut.
B. Two east-west cuts.
C. Two north-south cuts.
D. Holliday junctions cannot be resolved to produce gene conversion without crossing over.
2. A gene mutates into a dominant disease causing allele in 1 out of every 100,000 gametes. If
you observe 1,000,000 births, how many babies do you expect to be born with the disease?
A. 5 babies
B. 10 baby
C. 20 babies
D. 40 babies
E. 50 babies
3. A dominant lethal allele appears in 1 out of 100,000 gametes. About how many affected
individuals are expected per 100,000 births?
A. 1
B. 2
C. 4
D. 8
BIOL 3301 Exam 3
, 4. Consider the following DNA sequence:
5'-ATGCATGGT-3'
Which of the following sequences is most likely to result from mutation to the sequence above?
A. 5'-ATGATGGT-3'
B. 5'-ATGGCATGGT-3'
C. 5'-ATGGATGGT-3'
D. 5'-ATGAATGGT-3'
E. 5'-ATGTATGGT-3'
5. What is the inbreeding coefficient (F) between an uncle and his niece (shown in the pedigree
below)?
A. (1/2)5 = 0.03125
B. 2(1/2)5 = 0.0625
C. 4(1/2)5 = 0.125
D. 2(1/2)3 = 0.25
E. 2(1/2)2 = 0.5
6. Gene X has two alleles (X1 and X2). X2X2 homozygotes are half as likely to survive from birth
to reproductive age as heterozygotes or X1X1 homozygotes (w11=1.0, w12=1.0, w22=0.5). A
population starts with 50 individuals of each genotype, and they survive with a probability given
BIOL 3301 Exam 3
