genetics test 4
In cancer cells, one allele of a tumor suppressor gene called p53 is frequently mutated so that the protein is inactive, not produced, or deleted. The other allele usually has a normal sequence, and the promoter remains intact, but the gene is not expressed. Sequencing with sodium bisulfite modification of DNA can be used to detect which cytosines are methylated. If cancer cell DNA is sequenced, which of the following results would be expected? - Cytosines in or near the promoter will not be methylated -Cytosines in the coding region will have an increased methylation -Cytosines in or near the promoter region will be methylated -There will be no differences in the methylation pattern of the promoter of p53 from a cancer cell and a normal cell
- Cytosines in or near the promoter region will be methylated.
For a recessive single-gene disorder, the concordance among dizygotic twins should be -25%. -0%. -50%. -75%.
- 25%
Consider the following DNA sequence, which codes the first portion of a long protein beginning at the ATG (AUG in mRNA) start codon. 5' ATG CCC CGC AGT AGG GGG TGG AGA 3' Which of the mutated sequences listed is most likely to be a deleterious mutation? -5' ATG CCC CGC AGT AGG GGG TGA AGA3' -5' ATG CCG CGC AGT AGG GGG TGG AGA3' -5' ATG CCC CGC AGT AGG GAG TGG AGA3'
- 5' ATG CCC CGC AGT AGG GGG TGA AGA 3'
Which of the following is an example of a base analog? -nitrous acid -nitrogen mustards -5BU -EMS -acridine dyes
- 5BU
Where is the IRE located in the regulation of ferritin translation? -3′ end of DNA -5′ end of DNA -5′ end of mRNA -3′ end of mRNA
- 5′ end of mRNA
A translocation that moves a gene from an area of euchromatin to heterochromatin would typically cause _____ in the expression of the gene. -a reduction -no change -an increase
- A reduction
What gene(s) is/are encoded in the Xic? -Xce -Xist -Tsix -Both the Tsix and Xist are genes are in the Xic region
- Both the Tsix and Xist are genes are in the Xic region
Epigenetics may play a role in cancer by -directly resulting in gene deletions. -causing translocations. -directly inducing inversion mutations. -causing a change in gene expression patterns.
- Causing a change in gene expression patterns.
The conversion of cytosine to uracil in DNA is an example of _____. -depurination -tautomeric shifts -deamination -none of the answers are correct.
- Deamination
An example of personalized medicine would be -treatment of diabetics with synthetic instead of natural insulin. -performing an appendectomy on a patient with appendicitis. -treatment of an infection based on the drug resistance of the bacterium. -determining the CYP2C9 alleles present to help set the patient's coumarin dose.
- Determining the CYP2C9 alleles present to help set the patients coumarin dose.
What are the general ways that tumor suppressors and oncogenes act? -Tumor suppressors inhibit the cell cycle and oncogenes stimulate the cell cycle. -Oncogenes inhibit the cell cycle and tumor suppressors stimulate the cell cycle. -Both tumor suppressors and oncogenes stimulate the cell cycle. -Both tumor suppressors and oncogenes inhibit the cell cycle.
- Tumor suppressors inhibit the cell cycle and oncogenes stimulate the cell cycle.
In the nucleotide excision repair system, which of the following proteins is responsible for recognizing a thymine dimer to be repaired? -UvrA/UvrB -UvrC -UvrD -None of the answers are correct.
- UvrA/UvrB
Regions of chromatin that are more compact are called __________; they are usually found __________ in the nucleus.
- heterochromatin; at the periphery
Translocations and inversions may cause which of the following?
- position effect
The results of the replica plating experiments by the Lederbergs supported which of the following theories?
- random mutation theory
For a single-gene disorder, the concordance among monozygotic twins should be -25% -100% -0% -75%
-100%
The term that refers to the linkage of alleles or molecular markers along a single chromosome is -dizygotic -diplotype -haplotype -monozygotic
-Haplotype
The term that indicates that cancer has begun to migrate to other parts of the body is ______. -metastatic -migration -epistasis -extravasation
-metastatic
The process of _______ removes amniotic fluid from a pregnant mother to examine fetal cells for genetic problems. -amniocentesis -in vitro fertilization -chorionic villus sampling -preimplantation genetic diagnosis
Amniocentesis
Most genes imprinted by methylation are silenced. What is one exception to this rule?
Igf2
Combinatorial factors include activators and repressors as well as -small effector molecules - proteins that alter the composition of nucleosomes -DNA methylation -all of the above
small effector molecules, proteins that alter the composition of nucleosomes, and DNA methylation.
You are working in a lab where you are studying a disease that is known to be caused by a single nucleotide change, although the effect this change ultimately has on the protein's structure/function is unknown. You have DNA samples from multiple patients that you suspect of having this disease. What is the most efficient way to test the samples for the relevant mutation? -DNA marking -DNA sampling -DNA sequencing -DNA analyzing
- DNA Sequencing
Which of the following are molecular mechanisms used in epigenetic gene regulation? -Dna Methylation -Covalent Histone modification -Chromatin Remodeling -all of the above
- Dna Methylation, Covalent Histone modification, Chromatin Remodeling
Which of the following statements are correct? -Environmental epigenetic changes can vary due to the exposure of the organism to different environmental conditions, while those programmed during development are the result of stimuli generated by the organism itself. -Environmental epigenetic gene regulation is typically reversible while developmental epigenetic gene regulation is typically not reversible. -Environmental epigenetic gene regulation only occurs in reptiles and insects, while developmental epigenetic regulation occurs in all animals. -Changes in gene expression based on environmental conditions are not considered normal while developmental changes are.
- Environmental epigenetic changes can vary due to the exposure of the organism to different environmental conditions, while those programmed during development are the result of stimuli generated by the organism itself.
What would be the result of a mutation in HSP90 that prevented its binding to the glucocorticoid receptor?
- Expression of the regulated genes would become constitutive.
What is the difference between genetic testing and genetic screening? -They use different tests and techniques to detect genetic mutations. -Genetic testing is concerned more with individuals and genetic screening is concerned with populations. -Genetic screening is concerned more with individuals and genetic testing is concerned with populations. -Genetic testing is concerned more with nonlethal syndromes and diseases, and genetic screening is concerned with lethal diseases and syndromes.
- Genetic testing is concerned more with individuals and genetic screening is concerned with populations.
The differentially methylated region (DMR) is associated with which of the following
- Genomic imprinting
What are histone variants? -histone proteins that have been modified by acetylation -histone proteins that have slightly different amino acid sequences and have specialized functions -histone proteins that have slightly different amino acid sequences but are found in nucleosomes throughout the chromosomes -histone proteins that have been modified by acetylation and phosphorylation
- Histone proteins that have slightly different amino acid sequences and have specialized functions.
In humans, a recent study has shown that maternal anxiety during pregnancy can diminish the methylation of the ICR located between the H19 and Igf2 genes of the embryo and fetus. How would this affect the expression of the maternal and paternal alleles of the Igf2 gene after the baby is born? -It would not affect the expression of the paternal allele, but the maternal allele would be inhibited. -It would not affect the expression of the paternal allele, but the maternal allele would be overexpressed. -It would not affect the expression of the maternal allele, but the paternal allele would be inhibited. -It would not affect the expression of the maternal allele, but the paternal allele would be overexpressed.
- It would not affect the expression of the maternal allele, but the paternal allele would be inhibited.
Which DNA repair process utilizes MutL, MutH, and MutS proteins in E. coli? -direct repair -mismatch repair -homologous recombination repair -base excision repair
- Mismatch repair
What kind of mutation would be expected both within oncogenes and tumor suppressor genes that would result in gain-of-function or loss-of-function, respectively? -neutral -silent -amplifications -missense
- Missense
What general transcription factor is most often affected by regulatory transcription factors? -TFIIF -TFIID -TFIIB -TFIIF
- TFIID
Gene methylation can be detected through the use of restriction endonucleases. Usually these are used in pairs where one enzyme will digest only unmethylated DNA in its recognition sequence while the other is insensitive to methylation. Which of the following statements is correct?
- The enzyme that is insensitive to methylation serves as a control to make sure the inability of the other enzyme to digest DNA is not due to a mutation.
A particular gene has a mutation in its NFR that causes it to bind abnormally tightly to histones. What effect would you expect this mutation has on the expression of this gene?
- The expression of the gene would be abnormally low or absent.
Locus heterogeneity can cause difficulties in pedigree analysis since - The inheritance of one gene is being analyzed - The inheritance of no genes are being analyzed - The inheritance of more than one gene is being analyzed
- The inheritance of more than one gene is being analyzed
A queen bee is larger than the female worker bees in a hive. The queen develops functional ovaries that allow her to produce up to 2000 eggs a day. What determines which bees become queen bees?
- The larvae raised on a diet of royal jelly
How would a mutation that increases the rate of GTP hydrolysis by the Ras protein affect the EGF signaling pathway and how would it affect cell growth? -The signaling pathway would be turned off faster and cell growth would be inhibited. -The signaling pathway would be turned off faster and cell growth would be stimulated. -The signaling pathway would stay turned on and cell growth would be stimulated. -The signaling pathway would stay turned on and cell growth would be inhibited.
- The signaling pathway would be turned off faster and cell growth would be inhibited.
The Avy allele of the Agouti gene involves the insertion of a transposable element upstream from the normal Agouti promoter. The transposable element carries a promoter that causes the overexpression of the Agouti gene. Mice carrying this allele tend to have coat colors that are more yellow than mice that don't have this transposable element. If pregnant female mice are fed a diet that contains chemicals that increase DNA methylation, how would you expect that this diet would affect the coat color of offspring carrying the Avy allele? -Their fur would be more yellow because the Agouti gene would tend to be over expressed. -Their fur would be less yellow (darker brown) because the Agouti gene would tend to be over expressed. -Their fur would be less yellow (darker brown) because the Agouti gene would tend to be under expressed. -Their fur would be more yellow because the Agouti gene would tend to be under expressed.
- Their fur would be less yellow (darker brown) because the Agouti gene would tend to be under expressed.
Which of the following is incorrect regarding the glucocorticoid hormones? -After interacting with the receptor, they release HSP90. -They interact with receptors located in the plasma membrane of the cell. -The receptors form a homodimer that travels to the nucleus. -The homodimer interacts with GRE, activating transcription.
- They interact with receptors located in the plasma membrane of the cell.
Genome wide association studies are used __________. -to describe the number of alleles for a specific gene -to identify the mutation that causes a disease -to find the total variation that occurs in human genomes -to identify single nucleotide polymorphisms that are near disease causing genes
- To identify single nucleotide polymorphisms that are near disease causing genes.
What would be a set of anticipated results from a "Lederberg" experiment? -Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 0 -Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 15 -Total number of colonies on a plate: 500 Total number of resistant colonies on replica plate with T1: 1500 -Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 1500
- Total number of colonies on plate: 1500. Total number of resistant colonies on replica plate with T1: 15
In the analysis of a family, you notice that males are more likely to contract a certain disease, and the daughters of affected males produce 50% of their sons affected with the disease. This disease is displaying which of the following patterns of inheritance? -X-linked recessive -autosomal recessive -autosomal dominant -None of these choices are correct.
- X-linked recessive
A temporary change in the structure of a nitrogenous base is called ______.
- a tautomeric shift
Which of the following integrate into the double-helix of DNA, interfering with DNA replication?
- acridine dyes
Mutations that change the configuration of a protein at a specific temperature are called ____ mutations.
- conditional
The complete loss of either a guanine or adenine from DNA is an example of _____. -depurination -tautomeric shifts -deamination -none of the answers are correct.
- depurination
How does position effect influence gene expression? -The movement of the genetic material on the chromosome by inversions or translocations may place a coding sequence near a new regulatory region, thus activating the expression of the gene. -The movement of the gene may place it into a region that is highly condensed. -The movement of a gene may remove it from its normal promoter, thus silencing the gene. -All of the answers are correct.
-All of the answers are correct.
After screening a colony of bacteria for a given gene, you discover 100 mutant colonies out of 3 million total colonies. What is the mutation rate for this gene in the population? - 3.0x10^5 - 1.0 x 10^-5 - 1.0 x 10^5 - 3.3 x 10^-5
3.3E-5
Following mitosis, the two daughter cells usually have __________ pattern of facultative heterochromatin and __________ pattern of constitutive heterochromatin as was present in the mother cell. -a different; the same -the same; a different -the same; the same -a different; a different
the same; the same