Genetics Exam questions and
answers graded A+
For the following two questions, consider the following double-stranded DNA sequence:
5'-ATCATGCCATG-3'
3'-TAGTACGGTAC-5'
1) How many hydrogen bonds are represented in this double helix?
A) 16 B) 9 C) 20 D) 27 E) 8 - ANS✅✅D
5'-ATCATGCCATG-3'
3'-TAGTACGGTAC-5'
2) How many phosphodiester bonds are represented in this double helix?
A) 9 B) 23 C) 8 D) 20 E) 16 - ANS✅✅D
aa Bb Cc DD Ee FF
3) How many different gametes can this individual produce?
A) 10 B) 6 C) 12 D) 8 E) 24 - ANS✅✅D
4) Suppose only one of the gametes is randomly selected. What is the probability that the gamete
with the following combination of alleles is selected?
abCDeF
A) 1/12 B) 1/24 C) 1/8 D) 1/4 E) 1/6 - ANS✅✅C
5) InDrosophila virilis, nuclei of somatic cells contain 12 chromosomes while nuclei of sperm cells
contain only 6 chromosomes. What does "n" equal for this species?
A) 12
B) 24
C) 3
D) 6 or 12, depending on cell type
E) 6 - ANS✅✅E
, 6) Which evolutionary process relies on the premises that individuals with the best adaptations are
most successful at reproducing and leave more offspring than those with less adaptive forms
and that those adaptations have genetic basis?
A) migration
B) natural selection
C) mutation
D) population genetics
E) random genetic drift - ANS✅✅B
7) Consider a cross between two individuals with the following genotypes at three traits that assort
independently:
Rr Ss TT x rr Ss Tt
What is the probability that an offspring will be R/r; s/s; T/T?
A) 5/8 B) 1/16 C) 1/4 D) 1/8 E) 3/8 - ANS✅✅B
8) Consider the cross of the previous question , and assume all capital alleles are dominant. What is
the probability of having an offspring that shows all the dominant traits?
A) 3/4 B) 3/8 C) 1/4 D) 1/8 E) 3/16 - ANS✅✅B
9) Mutations at theRb gene lead to dominant cancer that has incomplete penetrance. How is the
penetrance explained?
A) Cancer will develop in Rb+Rb- individuals when cells become homozygoues for the Rballele
after rare mitotic recombination events.
B) Penetrance is due to the interaction with the environment.
C) Rb-Rb- is lethal
D) Incomplete penetrance is due to interactions with other genes.
E) There is codominance. - ANS✅✅A
10) Crossingover involves the breakage and reunion of DNA molecules from...
A) non-homologous nonsister chromatids
answers graded A+
For the following two questions, consider the following double-stranded DNA sequence:
5'-ATCATGCCATG-3'
3'-TAGTACGGTAC-5'
1) How many hydrogen bonds are represented in this double helix?
A) 16 B) 9 C) 20 D) 27 E) 8 - ANS✅✅D
5'-ATCATGCCATG-3'
3'-TAGTACGGTAC-5'
2) How many phosphodiester bonds are represented in this double helix?
A) 9 B) 23 C) 8 D) 20 E) 16 - ANS✅✅D
aa Bb Cc DD Ee FF
3) How many different gametes can this individual produce?
A) 10 B) 6 C) 12 D) 8 E) 24 - ANS✅✅D
4) Suppose only one of the gametes is randomly selected. What is the probability that the gamete
with the following combination of alleles is selected?
abCDeF
A) 1/12 B) 1/24 C) 1/8 D) 1/4 E) 1/6 - ANS✅✅C
5) InDrosophila virilis, nuclei of somatic cells contain 12 chromosomes while nuclei of sperm cells
contain only 6 chromosomes. What does "n" equal for this species?
A) 12
B) 24
C) 3
D) 6 or 12, depending on cell type
E) 6 - ANS✅✅E
, 6) Which evolutionary process relies on the premises that individuals with the best adaptations are
most successful at reproducing and leave more offspring than those with less adaptive forms
and that those adaptations have genetic basis?
A) migration
B) natural selection
C) mutation
D) population genetics
E) random genetic drift - ANS✅✅B
7) Consider a cross between two individuals with the following genotypes at three traits that assort
independently:
Rr Ss TT x rr Ss Tt
What is the probability that an offspring will be R/r; s/s; T/T?
A) 5/8 B) 1/16 C) 1/4 D) 1/8 E) 3/8 - ANS✅✅B
8) Consider the cross of the previous question , and assume all capital alleles are dominant. What is
the probability of having an offspring that shows all the dominant traits?
A) 3/4 B) 3/8 C) 1/4 D) 1/8 E) 3/16 - ANS✅✅B
9) Mutations at theRb gene lead to dominant cancer that has incomplete penetrance. How is the
penetrance explained?
A) Cancer will develop in Rb+Rb- individuals when cells become homozygoues for the Rballele
after rare mitotic recombination events.
B) Penetrance is due to the interaction with the environment.
C) Rb-Rb- is lethal
D) Incomplete penetrance is due to interactions with other genes.
E) There is codominance. - ANS✅✅A
10) Crossingover involves the breakage and reunion of DNA molecules from...
A) non-homologous nonsister chromatids
