Intro to Genetics Final Exam Questions with Verified Answers

Intro to Genetics Final Exam
Questions with Verified Answers

1. Mendel's first and second laws state that:
A) linked loci do not assort independently
B) unlinked loci segregate equally and alleles assort independently.
C) homologous chromosomes pair in meiosis and assort independently
D) linked loci are often inherited together
E) alleles segregate equally and unlinked loci assort independently - ANSWERSE)
alleles segregate equally and unlinked loci assort independently

In humans, ABO blood groups are determined by three alleles: alleles IA and IB are
codominant and both are dominant to the third allele i. MN blood groups are determined
by two codominant alleles M and N. A mistake happened in a big hospital, and parents
with phenotypes AB M and B N cannot identify their new born. Below are given
phenotypes of five new born kids, one of which belongs to this couple. Which one?
A) AB M
B) B N
C) O MN
D) B M
E) A MN - ANSWERSE) A MN

Parents of genotypes AABBCC and aabbcc (all loci are linked) are crossed to produce
F1. An F1 individual is test crossed to produce the following F2 phenotypes: abc, 244;
AbC, 93; ABc 156; aBC, 5; abC 151; ABC, 250; Abc, 6; aBc, 95. What was the
genotype (including gene order) of the F1 individual?
A) CAB / cab
B) aBc / AbC
C) BCA / bca
D) AbC / aBc
E) ABC / abc - ANSWERSA) CAB / cab

With regards to the previous question, what is a map distance from A to B?
A) 51.7 m. u.
B) 49.4 m. u.
C) 31.8 m. u.
D) 19.9 m. u.
E) 18.6 m. u. - ANSWERSD) 19.9 m. u.

With regards to the previous two questions what is a map distance from B to C?
A) 51.7 m. u.
B) 49.4 m. u.

,C) 31.8 m. u.
D) 19.9 m. u.
E) 18.6 m. u. - ANSWERSA) 51.7 m. u.

With regards to the previous three questions, how much interference was observed in
this cross?
A) 0%<I<20%
B) 20% < I < 40%
C) 40% < I < 60%
D) 60% < I < 80%
E) 80% < I < 100% - ANSWERSE) 80% < I < 100%

7. In partially diploid cells of E. coli created by conjugation, there are two copies of lac
operon: one copy on the chromosome and another on the F' factor. The genotype of
cells is:
+-++--++-+I P O Z Y / I P O Z Y . In the presence of an inducer, which of the following
statements
is true?
A) Both Z and Y proteins are produced
B) Neither Z, nor Y proteins are produced
C) Z protein is not produced, but Y protein is produced
D) Z protein is produced, but Y protein is not
E) Both proteins are produced, but only if IPTG and not lactose is an inducer -
ANSWERSC) Z protein is not produced, but Y protein is produced

Suppose you perform a cross AB x ab and analyze asci produced by a meiocyte. Which
of the following statements IS NOT true?
A) 10% of individual spores will indicate recombination between A and B
B) 20% of asci will have an MII segregation pattern for the B locus
C) 40% of asci will have an MII segregation pattern for the A locus
D) 20% of individual spores will indicate recombination between A and B
E) the number of cross-overs between the loci A and B equals to the number of cross-
overs between the centromere and the locus B. - ANSWERSD) 20% of individual
spores will indicate recombination between A and B

DNA fingerprint of a child represents:
A) an exact copy of the father's fingerprint.
B) an exact copy of the mother's fingerprint
C) a sum of the two partial parental fingerprints
D) a sum of the two parental fingerprints
E) has no resemblance with parental fingerprints - ANSWERSC) a sum of the two
partial parental fingerprints

Suppose that the following enzymatic pathway is used to synthesize amino acid
histidine in Neurospora:

, enzyme A enzyme B enzyme C Precursor ------------> Imidazole ---------> Histidinol
-----------> Histidine
These enzymes are encoded by three unlinked genes A, B and C respectively. A
prototrophic strain with the genotype ABC is crossed to an auxotroph (triple mutant
abc). What proportion of spores do you expect to produce a colony on a minimal
medium without any of these three substances?
A) 0
B) 1/16
C) 1/8
D) 1/4
E) 1/2 - ANSWERSC) 1/8

With regards to the previous question, what proportion of spores do you expect to
produce a colony on a minimal medium supplemented with histidinol?
A) 0
B) 1/16
C) 1/8
D) 1/4
E) 1/2 - ANSWERSE) 1/2

With regards to the previous two questions, if you were to analyze results of the above
cross (ABC to abc with all loci unlinked) using a chi-square test, how many degrees of
freedom would you determine?
A) 1
B) 3
C) 7
D) 9
E) 11 - ANSWERSC) 7

The haploid chromosome number in humans is 23. What is the total number of
CHROMATIDS per a cell immediately after telophase I of meiosis (assuming there was
a cell division)?
A) 23
B) 46
C) 69
D) 92
E) 184 - ANSWERSB) 46

You cross two plants with the following genotypes AaBBDdEeff x aaBbDDEeFf.
Assuming that all loci are unlinked, what proportion of their progeny is going to have the
genotype AaBbDdeeff?
A) 0%
B) 1.0%
C) 1.6%
D) 3.5%
E) 3.6% - ANSWERSC) 1.6%