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WorksheetsQuiz 7: Topic MUTATION
Total questions: 35
Worksheet time: 26mins
Errors during DNA replication, repair or recombination can lead to base-pair substitutions. Such changes are called ____________________
conditional mutations.
mutagens.
spontaneous mutations.
saltatory changes.
Colchicine acts as a mutagen which
stimulates DNA replication.
inhibits formation of spindle fibres.
causes breaking up of chromosomes into fragments.
changing the sequence of bases in DNA.
Sickle cell anaemia shows the changes in the DNA base sequence which is also called as ____________mutation.
point
nonsense
chromosomal
frameshift
In sickle-cell anaemia, ________________
glutamic acid is substituted with valine.
glutamic acid is substituted with proline.
valine is substituted with glutamic acid.
valine is substituted with proline.
Hydroxylamine is a mutagen. It converts cytosine to a compound which pairs up with adenine. If DNA is treated with hydroxylamine, the mutation which results is an example of a base ________
deletion.
insertion.
inversion.
substitution.
A mutation that replaces one amino acid in a protein with another is called a ____________ mutation.
frameshift
recombinant
nonsense
missense
What is the effect of a nonsense mutation in a gene?
It changes an amino acid in the encoded protein.
It has no effect on the amino acid sequence of the encoded protein.
It introduces a stop codon into the mRNA.
It alters the reading frame of the mRNA.
Substitution of one base pair for another can result in a ____________ mutation that results in the conversion of an amino acid specifying codon to a termination codon.
nonsense
frameshift
chromosomal
missense
A frameshift mutation could result from
a base insertion only.
a base deletion only.
a base substitution only.
either an insertion or a deletion of a base pair.
Frameshift mutation is caused by base insertion or deletion EXCEPT in the case where the number of base pair involved is
one.
two.
six
seven.
Which point mutation would be most likely to have catastrophic effect on the functioning of a protein?
A base-pair substitution
A base deletion near the start of a gene
A base insertion or deletion near the end of the coding sequence, but not in the terminator codon
Deletion of three bases near the start of the coding sequence, but not in the initiator codon
The normal human karyotype contains ________________ autosomes.
22
23
44
46
Karyotyping is useful for determining:
the number of chromosomes in an individual.
if a specific gene or trait is missing from a chromosome.
if gene mutations have occurred.
the presence of sickle cell anemia.
A normal gene sequence in a chromosomal sequence is ABCDEFGH. If it is changed to ABCGH, a _______________ has occur; if changed to ABCABCDEFGH, a ______________ has occurred; and if changed to ABCFEDGH, an ______________ has occurred.
Deletion; duplication; inversion
Duplication;deletion;inversion
Inversion;deletion;duplication
None of the above.
One possible result of chromosomal breakage can be that a fragment reattaches to the original chromosome in a reverse orientation. This is called _______________
disjunction.
translocation.
deletion.
inversion.
Which of the following causes chromosomes duplication?
A chromosomal segment attaches to its homolog
Homologous chromosomes do not separate during meiosis II
A chromatid from a chromosomes fails to separate during meiosis II
Deletion of chromosomal segment
Translocation occurs when:
part of a chromosome breaks off and attaches to a non-homologous chromosome.
part of a chromosome breaks off and attaches to a homologous chromosome.
crossing-over events occur.
genes move from one area on a chromosome to another area on the same chromosome.
Aneuploidies describe:
a phenomenon that only occurs in plants.
a condition in which an extra chromosome is present or one is absent.
a defect that is always fatal in humans and an uncommon condition in humans.
mutations that almost always have a beneficial effect on an individual.
Autosomal aneuploidies arise by:
chromosome breakage and rejoining.
non-disjunction.
errors in crossing-over.
mistakes in chromosome replication and mutation.
Cri-du-chat syndrome arises from:
trisomy for chromosome 5.
deletion of part of chromosome 5.
a 14/21reciprocal translocation.
nondisjunction and a duplication of part of chromosome 15.
Nondisjunction involving the X chromosomes occurs during oogenesis and produces two kinds of eggs, XX and O (no X chromosomes). If normal sperms fertilize the two types of eggs, which are the possible genotypes produced?
XX and XY
XXY and XO
XYY and XO
YY and XO
Which of the following statements is FALSE regarding non-disjunction?
Non-disjunction only happens during anaphase I meiosis.
Abnormalities in the number of sex chromosomes can happen.
Turner syndrome is a result of non-disjunction.
It may produce a polyploidy.
Turner syndrome is an example of a _____________ condition.
monosomic
disomic
trisomic
polyploid
Autosomal monosomy is NOT seen in live births because:
its effects are so small as to be overlooked and its effects do not set in until adulthood.
its effects are so lethal as to cause spontaneous abortion early in pregnancy.
it only occurs in sex chromosomes and therefore does affect non-reproductive function.
None of the above.
Down syndrome is an example of a _____________ condition.
monosomic
disomic
trisomic
polyploidy
Persons having an XXY karyotype are nearly normal males but produce few or no sperm. They have _____________ syndrome.
Turner
Klinefelter
Down (trisomy form)
Phenylketonuria
Persons having an XO karyotype are sterile females. They have __________ syndrome.
Turner
Klinefelter
Down (trisomy form)
Phenylketonuria
Which syndrome is represented by the following variation in chromosome number?
( 47, +21 ) : Klinefelter syndrome
( 47, XXY ) : Turner syndrome
( 45, X ) : Down syndrome
( 47, +21 ) : Klinefelter syndrome
( 47, XXY ) : Down syndrome
( 45, X ) : Turner syndrome
( 47, +21 ) : Down syndrome
( 47, XXY ) : Klinefelter syndrome
( 45, X ) : Turner syndrome
( 47, +21 ) : Down syndrome
( 47, XXY ) : Turner syndrome
( 45, X ) : Klinefelter syndrome
Polyploidy:
may be the result of more than one sperm fertilizing an egg.
is not lethal in humans.
may be the result of the failure of a chromosome to separate during meiosis.
can be due to non-disjunction for a chromosome.
Polyploidy is:
the presence of more than two of a certain chromosome.
more than two of a certain chromosome.
the presence of multiple sets of chromosomes.
the general term for conditions such as Down or Turner syndrome.
An organism with multiple sets of chromosomes from different species is called….
an autopolyploid.
an allopolyploid.
a hybrid polyploidy.
a sterile hybrid.
Which of the following may result in polyploidy?
I Treatment with colchicine
II Crossing over
III Independent assortment of chromosomes
IV Nondisjunction
I and II
I and IV
II and III
II and IV
What type of mutation has chromosomes PQRSTUVWXY undergo to become PRSTUWVXY?
Deletion
Inversion
Substitution
Insertion
If a gamete with chromosome number (n+1) is fertilized by a normal gamete, the resulting zygote is known as
Aneuploidy
Trisomy
Monosomy
Polyploidy
Which of the following types of gene mutation causes frame shift mutation?
Single base insertion
Two base inversion
Single base deletion
Single base substitution
