Genetics Exam 3 Clicker Questions

Imagine that an RNA polymerase is transcribing a segment of DNA that contains the following sequence: 5′-AGTCTAGGCACTGA-3′3′-TCAGATCCGTGACT 5′What will be the sequence of that RNA? A. 5′-AGUCUAGGCACUGA-3′ B. 3′-AGUCUAGGCACUGA-5′ C. 5′-AGTCTAGGCACTGA-3′ D. 3′-AGTCTAGGCACTGA-5′

A. 5′-AGUCUAGGCACUGA-3′

1B. If the AraC protein works as a gene repressor, would you expect araA RNA levels to be high or low in the presence of arabinose in araC- mutant cells? A. High B. Low

A. High

2C. If the AraC protein works as a gene repressor, would you expect araA RNA levels to be high or low in the absence of arabinose in araC- mutant cells? A. High B. Low

A. High

The antibiotic tetracycline is useful for acne treatment, among other things. Tetracycline blocks the attachment of aminoacyl tRNAs (amino-acid bound tRNAs) to the A site of the bacterial ribosome. Which of the following would you expect to happen if tetracycline were added prior to initiation of translation? A. Translation would not happen. B. Translation would not be affected. C. The end product only has 2 amino acids. D. The end product only has 1 amino acid.

A. Translation would not happen

2c. What do you predict will happen to Tre-ase transcription in the presence of trehalose if you were to create a version of the TreA protein that will constitutively bind to the "A" site in the Tre-ase promoter? A. Tre-ase will not be transcribed B. Tre-ase will be transcribed.

A. Tre-ase will not be transcribed

Which of the following correctly completes the following statement? RNA interference (RNAi) ___________. A. triggers degradation of RNA transcripts containing homologous sequences B. aborts translation of the principal open reading frame because of the presence of a smaller open reading frame upstream in the mRNA C. initiates the lytic cycle of the bacteriophage D. activates transcription in yeast cells. E. affects alternative splicing in eukaryotes

A. triggers degradation of RNA transcripts containing homologous sequences

Which of the following is the start codon? tRNA mRNA rRNA ATG UGA CGA

ATG (AUG)

What is the most likely mode of inheritance of this speech disorder, given that the FOXP2 mutation is a rare allele? Autosomal dominant Autosomal recessive Sex-linked dominant Sex-linked recessive

Autosomal dominant

If the bacterial cell has abundant tryptophan in its environment, would it spend energy to make more? A. Yes B. No

B. No

Which of the following statements about RNAi is true? A. The RNAi mechanism is found only in plants and animals. B. RNAi is induced when double-stranded, foreign RNA is present in the cell. C. RISC uses the siRNA duplex to locate complementary foreign RNA molecules. D. siRNAs bind to miRNAs to induce RNAi.

B. RNAi is induced when double-stranded, foreign RNA is present in the cell.

Worksheet 3A. Why is glutamine-dependent binding to the operon a useful property for the glutamine repressor? Select the one that is FALSE. A. If sufficient glutamine is present in cells, the glutamine repressor will block the synthesis of enzymes that would make more glutamine. B. The results are consistent with glutamine acting as a gene activator for the glutamine operon. A gene activator must bind to the promoter regions of the so as to stimulate their transcription. C. If cells are starved for glutamine, the unoccupied repressor would not bind to the DNA, and the enzymes that synthesize glutamine would be induced. D. These conditions permit a direct connection between the levels of glutamine and the expression of glutamine-synthesizing enzymes.

B. The results are consistent with glutamine acting as a gene activator for the glutamine operon. A gene activator must bind to the promoter regions of the so as to stimulate their transcription.

Imagine that an RNA polymerase is transcribing a segment of DNA that contains the following sequence: 5′-AGTCTAGGCACTGA-3′3′-TCAGATCCGTGACT 5′ If the polymerase is transcribing from this segment of DNA from left to right, which strand (top or bottom) is the template? A. top B. bottom

B. bottom

Which of the following statements about iPS cells is false? A. iPS cells are created by adding a combination of transcription regulators to a fibroblast. B. iPS cells created from mouse cells can differentiate into almost any human cell type. C. Stimulation by extracellular signal molecules causes iPS cells to differentiate. D. During the de-differentiation process to become an iPS, the fibroblast will undergo changes to its gene expression profile.

B. iPS cells created from mouse cells can differentiate into almost any human cell type.

The distinct characteristics of different cell types in a multicellular organism result mainly from the differential regulation of the _________________. A. replication of specific genes. B. transcription of genes transcribed by RNA polymerase II. C. transcription of housekeeping genes. D. proteins that directly bind the TATA box of eukaryotic genes

B. transcription of genes transcribed by RNA polymerase II.

A promoter is important because: A. It is a RNA molecule that serves as a primer. B. It only has one strand that can easily be transcribed. C. It recruits the enzyme that produces RNA. D. It unwinds DNA strands and allows one strand to be transcribed.

C. It recruits the enzyme that produces RNA.

A biofuel company finds that the yeast strain they have been using becomes less tolerant to ethanol. The company also notices that the "bad" yeast strain contains no dehydrogenase protein, which is involved in ethanol tolerance and is present in a normal yeast strain. Interestingly, the dehydrogenase mRNA in the "bad" yeast strain is the same as the one in a normal yeast strain. Which of the following might result in decreased ethanol tolerance in the "bad" yeast strain? A. The promoter of the dehydrogenase gene in the "bad" yeast strain is absent. B. The "bad" yeast strain has a mutated RNA polymerase. C. Ribosomes in the 'bad' yeast strain are unable to bind to the dehydrogenase mRNA. D. The dehydrogenase gene can't replicate in the "bad" yeast strain.

C. Ribosomes in the 'bad' yeast strain are unable to bind to the dehydrogenase mRNA.

Why is the dogma "one gene—one protein" not always true for eukaryotic genes? A. There are multiple ways that a DNA sequence can be transcribed into RNA B. Introns are removed from the DNA transcript and some exons can be spliced differently C. The primary RNA transcript can be alternatively spliced, producing distinct mRNAs that are translated into distinct proteins. D. The same mRNA can be translated into different amino acid polypeptide chains.

C. The primary RNA transcript can be alternatively spliced, producing distinct mRNAs that are translated into distinct proteins.

Will the trp operon be transcribed when the Trp repressor is mutated (in a normal haploid bacterium) such that it:Can't bind tryptophan? A. Yes, but only when Trp levels are low B. Yes, but only when Trp levels are high C. Yes, always D. No, never

C. Yes, always

Which of the following statements about miRNAs is false? A. One miRNA can regulate the expression of many genes. B. miRNAs are transcribed in the nucleus from genomic DNA. C. miRNAs are produced from rRNAs. D. miRNAs are made by RNA polymerase.

C. miRNAs are produced from rRNAs

Worksheet 3B. What would you expect to happen to the regulation of the enzymes that synthesize glutamine in cells expressing a mutant form of the glutamine repressor that cannot bind to DNA? The genes of the operon would ___.

C. only be expressed when glutamine levels were low

What happens during transcription? A.DNA nucleotides duplicate. B. DNA nucleotides are converted to amino acids C. RNA nucleotides become double-stranded D. DNA nucleotides are converted into RNA nucleotides E. DNA nucleotides code for the genetic code

D. DNA nucleotides are converted into RNA nucleotides

Your employers find that mouse skin cells are more tolerant to high concentrations of ethanol than their stomach cells. How can you explain it? A. Stomach cells are more exposed to ethanol so that the ethanol tolerance proteins change back into mRNA. B. Skin cells contain extra DNA sequences that encode ethanol tolerance proteins. C. Stomach cells have fewer RNA polymerases. D. Ethanol stimulates the expression of ethanol tolerance genes in skin cells but not in stomach cells. E. Stomach cells don't have restriction enzymes that can digest ethanol.

D. Ethanol stimulates the expression of ethanol tolerance genes in skin cells but not in stomach cells.

Will the trp operon be transcribed when the Trp repressor is mutated such that it always binds the operator, even in absence of tryptophan? (in a bacterium with a second, normal copy of the Trp repressor) A. Yes, but only when Trp levels are low B. Yes, but only when Trp levels are high C. Yes, always D. No, never

D. No, never

FOXP2 protein is found in certain but not all brain cells in the same individual; how is this possible? A.Some brain cells don't have Chromosome 7. B.FOXP2 DNA is only present in some brain cells. C. Some brain cells don't have ribosomes. D. The transcription factor to initiate FOXP2 transcription is only produced in some brain cells. E. Some brain cells contain more DNA.

D. The transcription factor to initiate FOXP2 transcription is only produced in some brain cells.

You see large pharmaceutical market potential for ethanol tolerant mice. Since protein X (see previous question) is NOT found in normal mice, you decide to create X transgenic mice. A few months later, your employers make the X transgenic mice and perform an ethanol tolerance assay (feed mice with ethanol and record the illness rate after 6 hours). The results are shown in this table. Which of the following statements may be true? A. Your employers did a good job. B. The non-transgenic mice have mutations in the X DNA sequence. C. The transgenic mice contain thermophilic anaerobic bacteria in the cells. D. Your employers might have switched the mice labels. E. Your employers might have injected the X protein but not the X recombinant DNA in the zygotes.

E. Your employers might have injected the X protein but not the X recombinant DNA in the zygotes.

In the eukaryotic genome, which of the following contributes to the protein-coding portion of the gene? Exons Introns Promoters Enhancers

Exons

The quantity of protein that can be translated from a given mRNA depends in part on the mRNAs ______. Nucleotide number Longevity Sugar-phosphate backbone

Longevity

What is the amino acid sequence of the protein produced by the mRNA molecule:  5′ AUGUGCAUUGACGUG3′ Met-Cys-IIe-Asp-Val Val-Asp-Leu-Arg-Val Cys-IIe-Asp-Val

Met-Cys-IIe-Asp-Val

Which of the following is bound by RNA Polymerase and directs the beginning of transcription? Exons Introns Promoters Enhancers

Promoter

Which of the following is involved in translation? Promoter Ribosomes Cytoplasm Nucleus RNA Polymerase Double-stranded DNA RNA Protein

Ribosomes, Cytoplasm, RNA = PROTEIN IS PRODUCT

True/False: Gene expression can be regulated at the level of RNA processing, alternative patterns of splicing, or mRNA stability.

True

True/False: The transcription complex in eukaryotes consists of numerous protein components that are recruited to the promoter of a gene whose chromatin has been suitably reconfigured. True False

True

Which of the following would result from transcription of this DNA template strand: 3′ AAGTAATTAAC5′? a. 3′ AAGTAATTAAC5′ b. 5′ UUCAUUAAUUG3′ c. 5′ TTCATTAATTG3′ d. 3′ UUCAUUAAUUG5′

b. 5′ UUCAUUAAUUG3′

A regulatory base sequence in eukaryotic cells that increases the rate of transcription of nearby genes regardless of orientation is called a(n) _______________. enhancer promoter operator operon

enhancer

An operon consists of all of the following except the ____. structural genes operator enhancer promoter

enhancer

_______________________ refers to heritable changes in gene expression that are not due to changes in the DNA sequence itself, but to something "in addition to" the DNA sequence, usually either chemical modification of the bases, or protein factors bound with the DNA. Epigenetic Epistasis Incomplete dominance Codominance

epigenetic

True/False: When considering the role of a gene in a particular process, the same allele can behave as a loss-of-function and a gain-of function mutation.

false

Which of the following mutations refers to a gene which is expressed in an inappropriate location? A. execution mutations. B. transformation mutations. C. transection mutations. D. heterochronic mutations. E. gain-of function mutants.

gain of function mutants

The molecular attractions that induce RNA folding are _____. covalent bonds Van der Waals forces hydrogen bonds ionic bonds

hydrogen bonds

Which molecule involved in transcription or translation contains codons? mRNA tRNA rRNA protein DNA

mRNA

What would you expect to happen to the regulation of the enzymes that synthesize glutamine in cells expressing a mutant form of the glutamine repressor that binds to DNA even when no glutamine is bound to it?

never be expressed regardless of glutamine concentration

Which of the following is involved in transcription? Promoter Ribosomes Cytoplasm Nucleus RNA Polymerase Double-stranded DNA RNA

promoter, nucleus, RNA Polymerase, Double-stranded DNA = RNA IS PRODUCT

Which of the following is part of the ribosome? tRNA mRNA rRNA ATG UGA CGA

rRNA

A(n) _____, when bound to a region near the promoter termed the operator, keeps transcription off Activator Repressor Operon enhancer

repressor

An allele that is highly methylated cannot be accessed by transcription machinery. This allele is... expressed transcribed silenced active

silenced

The base-pairs shown in black type indicate a codon for amino acid #553. What kind of mutation in the FOXP2 gene did the scientists discover in the mutant allele through DNA sequencing? missense nonsense frameshift silent

silent

Which of the following allows for a given eukaryotic gene to encode for multiple protein products? Splicing Alternative splicing Translation in frame operons

splicing

Which of the following brings amino acids for transfer to the growing polypeptide chain? tRNA mRNA rRNA ATG UGA CGA

tRNA

True or False? Developmental genes are often controlled by gradients of gene products, either within cells or across parts of the embryo.

true