Modern Genetics Final Exam Review
Questions and Answers 100% Pass.
A child with Turner Syndrome is found to be colorblind (an X linked recessive trait). The child's
mother and father both have a normal chromosome number and have normal vision (i.e., are not
colorblind). The sex chromosome number makeup of this child is _________. The
nondisjunction resulting in the child with Turner Syndrome must have occurred in her
_________. - answer✔XO; father
The Class ______ transposable elements typically comprise the largest fraction of eukaryotic
genomes because their ______ mode of transposition enables them to become more abundant -
answer✔1; copy-and-paste
Dicentric bridges and acentric fragments are produced during meiosis in a(n) -
answer✔paracentric inversion heterozygote
A displacement loop (D-loop) is most likely to form during - answer✔synthesis-dependent
strand annealing (SDSA)
The figure below illustrates mispairing that can arise when DNA is treated with EMS. Which of
the following represents the specific mutation that would result? ADD IMAGE - answer✔TA >
CG
The figure below illustrates the chromosome structure and cross-shaped pairing configuration for
a reciprocal translocation heterozygote. Which of the following is correct with regard to
segregation patterns and meiotic products? (up, upward movement to the cell on top; down,
downward movement to the cell on bottom) ADD IMAGE - answer✔T1 + T2 up; N1 + N2
down = complete and viable gametes
For nonautonomous DNA transposons to be mobile, they require a functional __________
enzyme encoded by a __________. - answer✔transposase; different DNA transposon
The genome of a cancer patient was investigated. This patient has a couple of potential cancer-
causing mutations that are genetically inherited. The genome of the patient's cancer tissue
showed that the copy number of the gene with the mutation was decreased from the normal
number of 2 to 1 - a phenomenon called loss of heterozygosity. The ____ of the wild-type gene
appeared to uncover the ______ phenotype. This gene is a candidate for _______. -
answer✔deletion, recessive, tumor suppressor gene
In Drosophila, individual X-linked genes are expressed at an approximately 2-fold higher level in
males versus in females. A consequence of this is that X-linked genes are expressed at similar
levels in males (XY) and females (XX). This phenomenon is known as - answer✔dosage
compensation
In humans, what kind of mutations would most likely cause cancer? - answer✔genetically
inherited mutation(s) and induced mutation(s).
In hybrid dysgenesis of fruit flies, the cytoplasm of ______ female does not carry RNA
interference against _______. As a consequence, the progeny with ______ male is sterile. -
answer✔laboratory, P-elements, wild
In one method of RNA interference, short hairpin (sh) RNA is transcribed from a plasmid DNA.
Yet, the final effective product for RNAi is short double-stranded (ds) RNA. How is shRNA
converted into short dsRNA? - answer✔An endonucleolytic cleavage activity removes a loop
from shRNA.
A ______ introduced to the third position of a tyrosine codon leads to a _______ mutation. Use
the genetic code to answer this question. - answer✔transversion, nonsense
The Luria and Delbruck fluctuation test demonstrated that mutations in E. coli that convey
resistance to T1 phage occur in response to exposure of E. coli to the T1 phage. - answer✔False
A negative consequence of transposable element activity for the host genome can be the
mutagenic effects of new transposable element insertions. In Drosophila, the R1 and R2 LINE
elements preferentially insert into the genes encoding ribosomal RNA. These genes are found in
long tandem arrays on the chromosome. The preferential insertion of R1 and R2 LINE elements
into these ribosomal RNA genes tends not to have a highly deleterious effect on the host because
- answer✔the long tandem arrays of ribosomal RNA genes typically consist of many copies, and
insertions into some of these copies is tolerated by the host
An organism that is trisomic would be best described by which of the following chromosomal
constitutions? - answer✔AABBCCC
A plant scientist studies a diploid species with 20 chromosomes in a haploid set. All the possible
_____ monosomic lines missing each chromosome were generated and found to be viable. The
resulting lines are expected to carry ______ chromosomes. Each monosomic line was crossed to
a homozygous recessive mutant (a/a). The cross with chromosome 8 monosomic line generated
______ % progeny with the mutant phenotype. It was concluded that the mutant gene a is located
on chromosome 8. - answer✔20, 39, 50
Proflavin and ICR-191 are ___________ that can cause ___________ mutations -
answer✔intercalating agents; INDEL
Recently, CRISPR/cas system is frequently used to delete or change a specific site of the
genome. Based on this description, the CRISPR/cas system is an example of methods used in -
answer✔targeted mutagenesis
Replicative transposition in bacteria involves transposition via an RNA intermediate. -
answer✔False
A researcher found two paralogous proteins, A and B, in the human genome. The protein A is an
enzyme involved in chromosome methylation, whereas the protein B has lost the enzyme
activity, but is a repressor for transcription of some genes. What is the most likely scenario? -
answer✔The protein B has lost the methylation activity due to mutation and yet retains DNA-
binding activity for genes that it regulates.
A researcher frequently uses transposon for genetic screening. Which is the FALSE explanation
why he or she does so? - answer✔Transposons are more readily inserted into genic regions.
The RNAi pathway can serve as a transposable element suppression mechanism by degrading -
answer✔the mRNAs produced by active transposable elements
The term 'sequencing coverage' (e.g., 3X coverage, 20X coverage), when applied in a genomics
context, refers to sequencing - answer✔the same base pair multiple times
This question provides you with an answer and requires you choose the best question.
Answer: Where two species (together with their common ancestor) share chromosomal structural
patterns in which chromosomal blocks possess the same genes in the same order. -
answer✔What is conserved synteny?
Which is FALSE about the mental disease caused by alteration in the FMR1 gene? -
answer✔During DNA replication, a loop structure in the template strand causes repeat
expansion.
Which is NOT a part of pyrosequencing in nextgen WGS sequencing? - answer✔The sequencing
products are separated in a gel.
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