BIO 208 Worksheet for Exam 4

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BIO 208 Worksheet 4
The review is not comprehensive
2011
1. Match the mutation with the best answer A – J. Each answer is used once.
_______G__ occurs in sperm or egg
A. point mutation
_________C occurs due to no particular agent
B. any mutation
____E_____ occurs due to chemical or environment C. spontaneous mutation
__F_______ does not result in an amino acid changeD. frameshift mutation
____H_____ causes the protein to be too short
E. induced mutation
____D____ shifts the reading frame of the message F. silent mutation
______A__ involves one DNA base only
G. germinal mutation
____B____ heritable change in DNA
H. nonsense mutation
______I_ DNA triplet expansion
I. trinucleotide repeat
2.
Compare sequences # 1 and #2. Characterize each mutation (there are 4) as to position in the
codon(1st, 2nd, or 3rd) and whether it is a transition (TS) or transversion (TV)
Sequence #1
Sequence #2 (mutant)
ATG GGA CCT ACA TAT GCC
ATG GCA TTT ACA TAA GCC
G-> C is a second position TV
C-> T is a 1st position TS, the other is a 2nd position
T-> A is a 3rd position TV
3. Characterize the mutations (a – e) using the following terms: Some of the mutations are described
with more than one term
Deletion
Nonsense mutation
a. TTC CAG AAA 
Point mutation
Frameshift mutation
Missense mutation
Trinucleotide Repeat
TTC CAG CAG CAG CAG CAG CAG CAG CAG AAA TRINUCLEOTIDE
REPEAT
b. ACTTTTGTTAAT 
c.
ACTGTTAAT DELETION
AUG CAG AUU AAC GCU GCA UAA 
met gln
ile
asn
ala
ala
stop
d. AUG CAG UCA AAC GCU GCA 
met gln ile asn
ala ala
e. AUG GAC UCA GCU 
met gln
ile
asn
AUG AGA UUA ACG CUG CAU AA FRAMESHIFT +
met
arg
leu
thr
leu
his
POINT MUT.
AUG CAG UAA NONSENSE + POINT MUT
met gln stop
AUG
met
CAC
his
UCA
ile
GCU
asn
MISSENSE + POINT
4. What do the following acronyms stand for?
UV
SNP
TS and TV
5. Fill in the correct number:
1
46
Cdk
XP
RB
DNA
SARS
2
2
20
4
3 billion
20,000
a. ____46__ chromosomes in a human somatic cell
b. ___1___ human genomes in a single human cell
c. ____2__ types of transitions that can occur
d. ___3 billion___ nucleotide base pairs in the human genome
e. __4-5____ approximate mutational events in the etiology of familial colorectal cancer
f. ___4___ types of transversions that can occur
g. ___2___ alleles mutated of RB to cause a loss of function
h. ___1___mutations in the beta globin gene that cause sickle cell disease
i. ___20___ amino acids in nature
j. ___20,000___ genes in a human genome
6.
Fill in - may use answer more than once or not at all
Benign
Apoptosis
Oncogene
Sickle cell
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
m.
n.
o.
p.
q.
r.
s.
Retinoblastoma
Metastasis
Angiogenesis
Colon cancer
Li Fraumeni
Xeroderma pigmentosum
Proto-oncogene
Fragile X syndrome
ANGIOGENESIS tumor releases molecule that interacts with blood vessel to promote vascularization
RETINOBLASTOMA childhood eye cancer initiated when two alleles of RB gene are mutated
BENIGN cancer forms in a connective capsule and is excised easily
RETINOBL. sporadic and familial forms
FRAGILE X trinucleotide repeat in gene promoter regions inactivates gene
COLON CANCER cancer requires ~ 4 separate mutations to develop
PROTOONCOGENE gene encodes a normal protein involved in cellular growth
APOPTOSIS cell suffers DNA damage that is irreparable and is this pathway is initiated
LI F. predisposition to cancer due to mutant p53 gene
XERODERMA P. A number of malignant melanomas form due to mutant DNA repair system
COLON CANCER, RETINOBLAS. Two cancers that involve mutant tumor suppressors
SICKLE CELL occurs due to mutation in 6th codon of beta globin gene
METASTASIS Movement of cancer cell from primary tumor to secondary location
ONCOGENE A normal gene involved in cellular growth is mutated to this form
XERODERMA P. extreme sensitivity to UV light
SICKLE CELL misshapen red blood cells block capillaries
XERODERMA P. mutation in DNA excision repair pathway
FRAGILE X defect in signaling between neurons, lessens synaptic plasticity
COLON CANCER polyp type tumor forms
7. Proteins. Fill in
Telomerase
p53
pRB
Cdk
cyclin
ras
EF2
Growth factor
Growth factor receptor
a. Telomerase enzyme immortalizes cells
b. Ras a signal transducer involved in stimulating cell growth
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c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
m.
n.
o.
p.
q.
E2F
bound by pRB in inactive form
Cyclin
binds a CdK
Ras
a kinase that phosphorylates other proteins
Growth factor, GF receptor, ras 3 proteins involved in stimulating cells to grow that when
mutant are called oncogenes
Growth factor receptor a transmembrane protein
Telomerase acts at the ends of chromosomes
Telomerase, p53, pRB, CDk, cyclin, ras E2F, GF, GFR = 9 proteins, a mutation in which can
lead to cancer
Growth factor
a hormone is one type
p53
can signal the cell to move to apoptotic pathway
p53 pRB
2 tumor suppressor proteins
Omit this one
binds to mdm2 to target for degradation
p53
mutations of gene encoding this protein observed in ~50% of cancers
p53 and pRB
knockout mice develop cancers early in life
pRB
interacts with E2F transcription factor
omit this one
free form results in an increase in the expression of p21 protein
8. Are the following associated with SNP or a gene (choose one for each) ?
a. 90% of all human genetic variation
SNP
b. 20,000 estimated in human genome
GENE
c. 3 million estimated in human genome
SNP
d. contains introns and exons
GENE
e. transcribed as a unit of mRNA
GENE
f. may not be responsible for disease but may be used as a genetic marker SNP
g. polymorphism
SNP
h. contains a promoter
GENE
9. Fill in using the appropriate letter – each letter is used once
A. Human Genome Project D. Pharmacogenomics
G. DNA polymorphism
B. Genetic predisposition E. Non-genetic factors
H. Personalized medicine
F. Presymptomatic testing
D the study of how an individual’s genetic inheritance affects the body’s response to drugs
H the ability to target a specific drug and dose to those individuals most likely to benefit
B An allele which may predispose an individual to a developing a particular disease
F A microarray test to test a person for disease before the development of noticeable disease symptoms
A Governmental and private effort to determine the sequence of 3 billion nucleotides of human DNA
G A small genetic change, or variation, that can occur within a person's DNA sequence
E Behavior, lifestyle, diet, physical activity that influence gene expression and disease progression
10. Discuss the following cellular situations with respect to cell growth
a. The cell cycle occurs too rapidly – will lead to abnormal, fast cell growth, too many cells, a
benign tumor or a malignant tumor
b. A DNA repair enzyme gene is mutated – mutations cannot be fixed. Because mutations are
occurring and being fixed all of the time, this is serious. XP is an example of a disease in which a
DNA repair system does not work.
c. A tumor suppressor is overproduced. The cell will not divide. This is not related to cancer
d. A growth factor receptor is overproduced. Too much growth factor will bind to the receptors and
the cell may receive extra growth signal. Could lead to cancer.
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e. A mutation in a growth factor gene causes too little growth factor to be produced. The cell will
not divide. Not cancer related
f. Angiogenesis is blocked. The tumor will not receive an adequate blood supply. It will shrink.
g. Apoptosis does not occur in an abnormal cell. The abnormal cell will persist, can divide to 2
abnormal cells and so on.
h. Normal mitosis occurs. Normal cell growth.
i. A cell becomes transformed – it is a cancer cell. Exhibits the cancer phenotype.
j. The RB gene promoter is nonfunctional due to a mutation. No promoter, no RB mRNA, n RB
protein. No suppression of tumors – the cell will not arrest at the checkpoint and will continue
without control in the cell cycle.
k. A knockout mouse has 2 copies of a non-functional p53 gene
l. A mouse is born with 1 functional copy of the p53 gene. One copy leads to enough p53 for the
cell to remain normal in terms of phenotype. This mouse is at a high risk of developing cancer as
if the other copy is mutated, it will lose the ability to regulate the G1-S checkpoint.
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