Mini-Test for Genetics
Exercise 1
Each column in the table below represents three nucleotides. Within each, fill in the
cells that are blank by using information from the cell that is not blank. Use the table
on the next page to help you
Template
strand
Nontemplate
strand
GGG
TAC
mRNA
tRNA
Amino Acid
CCU
UCG
Leu
First
Base
U
C
A
G
Second Base
Third
Base
U
C
A
G
UUU
phenylalanine
UCU
serine
UAU
tyrosine
UGU
cysteine
U
UUC
phenylalanine
UCC
serine
UAC
tyrosine
UGC
cysteine
C
UUA
leucine
UCA
serine
UAA
stop
UGA
stop
A
UUG
leucine
UCG
serine
UAG
stop
UGG
tryptophan
G
CUU
leucine
CCU
proline
CAU
histidine
CGU
arginine
U
CUC
leucine
CCC
proline
CAC
histidine
CGC
arginine
C
CUA
leucine
CCA
CAA
proline glutamine
CGA
arginine
A
CUG
leucine
CCG
CAG
proline glutamine
CGG
arginine
G
AUU
isoleucine
ACU
AAU
threonine asparagine
AGU
serine
U
AUC
isoleucine
ACC
AAC
threonine asparagine
AGC
serine
C
AUA
isoleucine
ACA
threonine
AAA
lysine
AGA
arginine
A
AUG (start)
ACG
methionine threonine
AAG
lysine
AGG
arginine
G
GUU
valine
GCU
alanine
GAU
aspartate
GGU
glycine
U
GUC
valine
GCC
alanine
GAC
aspartate
GGC
glycine
C
GUA
valine
GCA
alanine
GAA
glutamate
GGA
glycine
A
GUG
valine
GCG
alanine
GAG
glutamate
GGG
glycine
G
2. In pea plants, spherical seeds (S) are dominant to dented seeds (s). In a genetic
cross of two plants that are heterozygous for the seed shape trait, what fraction of the
offspring should have spherical seeds?
A None
B¼
C½
D¾
E All
3. A phenotypic ration of 3:1 in the offspring of a mating of two organisms
heterozygous for a single trait is expected when:
A the alleles segregate during meiosis
B each allele contains two mutations
C the alleles are identical
D the alleles are incompletely dominant
E only recessive traits are scored
4. Human blood type is determined by codominant alleles. There are 3 different
alleles known as IA, IB , and i. The IA and IB alleles are co-dominant and the i allele is
recessive.
The possible human phenotypes for blood group are type A, type B, type AB, and
type O. Type A and type B individuals can be either homozygous (IA IA or IB IB
respectively), or heterozygous (IAi or IBi, respectively).
A woman with type A blood and a man with type B blood could potentially have
offspring with which of the following blood types?
A type A
B type B
C type O
D all of the above
5. Hemophilia in humans is due to an X-chromosome mutation. What will be the
results of a mating between a normal (non-carrier) female and a hemophilic mlae?
A half of the daughters are normal and half of the sons are hemophilic
B all sons are normal and all daughters are carriers
C half of sons are normal and half are hemophilic: all daughters are carriers
D all daughters are normal and all sons are carriers
E half of daughters are hemophilic and half of daughters are carriers: all sons are
normal
6. Women have sex chromosomes of XX and men have sex chromosomes of XY.
Which of a man’s grandparents could not be the source of any of the genes on his Y
chromosome?
A Father’s mother
B Mother’s father
C Father’s father
D Mother’s mother, mother’s father, and father’s mother
E Mother’s mother
7. Which of the following describes a type of polymorphism that occurs within the
gene that causes Huntington’s disease?
A RFLP’s, “restriction fragment length polymorphisms”
B EST’s, “expressed sequence tags”
C STRP’s, “short tandem repeat polymorphisms”
D STS’s, “sequence tagged sites”
E None of the above
8. Which of the following is not one of the objectives of the Human Genome Project?
A Create a detailed genetic map of every human chromosome, with an average of 25% recombination frequency between markers
B Obtain a detailed physical map of every human chromosome, based on overlapping
recombinant DNA molecules cloned as yeast artificial chromosomes
C Clone human beings
D Determine the sequence of all expressed human genes by cDNA cloning and
sequencing
E Determine the complete DNA sequence of each human chromosome
9. When RFLP analysis is used to search for a human gene, the strategy is to first
locate?
A a known gene on the same chromosome
B an homozygous individual with a simple RFLP pattern
C a DNA sequence anywhere on the same chromosome
D any DNA marker co-inherited with the genetic trait of interest
E an exon of the disease gene
10. DNA fingerprint analysis is based on the “Southern” hybridisation technique. In
this method:
A Non-radioactive cellular RNA, separated by electrophoresis and blotted onto a
membrane filter, is tested for hybridisation with a radioactive gene-specific probe of
either RNA or DNA
B Radioactive DNA restriction fragments, separated by electrophoresis and blotted
onto a membrane filter are tested for hybridisation with a non-radioactive, genespecific probe of either RNA or DNA|
C Radioactive cellular RNA, separated by electrophoresis and blotted onto a
membrane filter is tested for hybridisation with a radioactive, gene specific probe of
either RNA or DNA
D DNA research is done south of the equator
E Non-radioactive DNA restriction fragments, separated by electrophoresis and
blotted onto a membrane filter are tested for hybridisation with a radioactive, gene
specific probe of either DNA or RNA
11. Probability calculations are used in forensic applications of DNA fingerprinting to
determine if:
A DNA from two different sources have matching alleles
B DNA samples were degraded before analysis
C A match between alleles of different DNA samples may have occurred by chance
D An unknown DNA sample is from a male or a female
E Alleles in the suspect’s DNA are different from alleles of a victim’s DNA
12. Results from a single locus probe DNA fingerprint analysis for a man and woman
and their four children are shown in the illustration. Which child, if any, can be
excluded as being the biological offspring of the father?
A Child 1
B Child 2
C Child 3
D Child 4
E None of the children can be excluded
13. Which of the following is NOT a potential source of DNA for forensic analysis?
A hair roots
B red blood cells
C epithelial cells in urine
D muscle tissue
E saliva
14. “Gene library” is a term used to describe:
A a computerised listing of known DNA sequences
B bacteria with plasmids containing DNA fragments representing the majority of the
genetic information from a plant or animal
C a collection of books about recombinant DNA technology
D a compilation of the amino acid sequences of protein coding genes
E a store that specialises in the sale of Levi’s
15. Which of the following tools of recombinant DNA technology is
INCORRECTLY paired with one of its uses?
A restriction endonuclease – production of DNA fragments for gene cloning
B DNA ligase – enzyme that cuts DNA, creating sticky ends
C DNA polymerase – copies DNA sequences in the polymerase chain reaction
D reverse transcriptase – production of cDNA from mRNA
E electrophoresis – RFLP analysis
16. The data below shows the results of electrophoresis of PCR fragments amplified
using probes for the site which has been shown to be altered in Huntington’s disease.
The male parent, as shown by the black box, got Huntington’s disease when he was
40 years old. His children include 6 (3,5,7,8,10,11) with Huntington’s disease, and
the age at which the symptoms first began is shown by the number above the band
from the PCR fragment.
What is the prognosis for the normal children, 4,6, and 9?
A 4 and 9 do not have the trait, and will not get Huntington’s disease, but 6 is likely to
start the disease when he reaches his father’s age of 40
B 4,6,and 9 are lucky and have not inherited the defect causing Huntington’s disease
C 4,6 and 9 will still develop Huntington’s disease at some point in their lives, since
the disease is inherited as a dominant trait
D Two of the three will develop the disease, since it is inherited as a dominant trait,
but the data does not allow you to predict which two
E 4,6 and 9 must be children of a different father and thus do not carry the trait for
Huntington’s disease
17. You have obtained a sample of DNA, and you transcribe mRNA from thisDNA
and purify it. You then separate the two strands of the DNA and analyse the base
composition of each strand and of the mRNA. You obtain the data shown in the table
below. Which strand of the DNA is the coding strand, serving as a template for
mRNA synthesis?
A G C T U
DNA strand #1 19.1 26.0 31.0 23.9 0
DNA strand #2 24.2 30.8 25.7 19.3 0
mRNA 19.0 25.9 30.8
A Strand 1
B Strand 2
C Both strands 1 and 2
D Neither strand 1 or 2
E Too little information to tell
0
24.3
18. Patient A’s karyotype is the nearly full-term fetus of a forty year old female.
Chromosomes were obtained from fetal epithelial cells acquired through
amniocentesis
Patient A’s karyotype
_______ ________ ________
1
2
3
________ ________
4
5
________ ________ ________ ________
6
7
8
9
________ ________ ________
10
11
12
________ ________ ________
13
14
15
________ ________
19
20
What diagnosis would you give patient A?
What clinical features would you expect?
________ ________ ________
16
17
18
________ ________
21
22
________
XX/XY
19. Patient B died shortly after birth, with a multitude of anomalies, including
polydactyly and a cleft lip. Chromosomes were obtained from a tissue sample
_______ ________ ________
1
2
3
________ ________
4
5
________ ________ ________ ________
6
7
8
9
________ ________ ________
10
11
12
________ ________ ________
13
14
15
________ ________
19
20
________ ________ ________
16
17
18
________ ________
21
22
________
XX/XY
What is the diagnosis?
20. A human geneticist determined the pedigree shown in the diagram with filled
symbols showing the affected individuals. How is this pattern of inheritance
described?
A autosomal dominant
B autosomal recessive
C sex-linked recessive
D sex-linked dominant
E none of these
21. For each of the following, tell whether it is an example of incomplete/partial
dominance, codominance, multiple alleles, genomic imprinting, polygenic
inheritance, epistasis, pleiotropy or none of these
A eye colour in humans/ polygenic
B ABO blood groups in humans/ codominance/ multiple alleles
C height in humans/ polygenic
D pink flowers in heterozygous snapdragons/ incomplete partial dominance
E Marfan syndrome/ pleiotropy
22. In humans, short fingers is dominant and long fingers is recessive. Widow’s peak
is dominant and straight hairline is recessive. A short-fingered man with a straight
hairline whose mother had long fingers married a long fingered woman with a
widow’s peak. The woman’s mother had a straight hairline. What proportion of the
offspring will be heterozygous for both traits? Hint- draw a pedigree
23. How many different DNA molecules 10 base pairs long are possible?
A 40
B 160
C 4,000
D 16,000
E 1,048,576
24. A man's grandfather had galactosemia. This is a rare autosomal recessive disease
caused by the inability to process galactose, leading to muscle, nerve, and kidney
malfunction. The man married a woman whose sister had galactosemia. The woman is now
pregnant with their first child.
a. Draw the pedigree as described.
b. What is the apparent mode of inheritance in this pedigree?
A autosomal dominant
B autosomal recessive
C sex-linked dominant
D sex-linked recessive
c. What is the genotype of the man’s father?
A AA
B Aa
C aa
D A_
d. What is the genotype of the man?
A AA
B Aa
C aa
D A_
e. What is the probability of the man carrying the recessive allele for galactosaemia?
A1
B½
C 2/3
D¾
f What is the genotype of the man’s wife?
A AA
B Aa
C aa
D A_
g What is the probability of the man’s wife carrying the recessive allele for galactosaemia?
A¼
B½
C 2/3
D¾
h. What is the combined probability of both the man and his wife being carriers of the
galactosaemia allele?
A 1/6
B¼
C 1/3
D½
i What is the probability their first child has galactosaemia?
A 1/6
B 1/3
C½
D 1/12
25. What is the site in the eukaryotic cell in which transcription takes place?
A endoplasmic reticulum
B nucleus
C ribosome
D plasma membrane
E all of the above
F none of the above