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1. Which of the following mutations results in constitutive repression of the lac operon?

A. Oc

B. I-

C. Is

D. I- and Is

C. Is

In the presence of the repressor molecule and free tryptophan, the trp operon is

A. induced.

B. constitutively transcribed.

C. repressed.

D. transcribed but not translated.

C. repressed.

The lac repressor can bind to

A. allolactose and DNA.

B. RNA polymerase.

C. RNA polymerase and DNA.

.D. B-galactosidase, permease, and transacetylase.

A. allolactose and DNA.

Compared to heterochromatin, euchromatin is nucleosomes.

_ in genes and comprised of

A. rich; densely-packed rich; loosely-packed

B. poor; densely-packed

D. poor; loosely-packed

A. rich; densely-packed rich; loosely-packed

Which of the following histone modifications neutralizes their charge?

A. methylation

B. phosphorylation

C. acetylation

D. All alter their charge.

C. acetylation

Histones, CpG islands, and imprinting control regions are similar in that they all can be

A. acetylated.

B. methylated

C. phosphorylated.

D. used as reporter genes.

B. methylated.

The expression of a single allele is associated with which of the following?

A. X-inactivation

B. Genomic imprinting

C. heterochromatin

D. euchromatin

B. Genomic imprinting

Which of the following are molecular mechanisms used in epigenetic gene regulation?

A. DNA methylation

B. covalent histone modification

C. chromatin remodeling

D. All of these choices are correct.

D .All of these choices are correct.

Into which gene of the CRISPR-Cas system are fragments of bacteriophage DNA inserted?

A. tracr

B. Crispr

C. Cas1

D. Cas2

E. Cas9

B. Crispr

What is the correct order of steps of the the CRISPR-Cas system?

A. adaptation, interference, expression

B. expression, adaptation, interference

C. adaptation, expression, interference

D. interference, adaptation, expression

C. adaptation, expression, interference

Assuming that glucose is absent and lactose is present, how would expression of the lac operon be affected if lacO was missing?

A. down-regulated

B. up-regulated

C. not affected

B. up-regulated

Suppose that a bacterial operon is repressible. Which combination of effector molecules and regulatory proteins could be involved?

A. inhibitor and repressor

B. inducer and repressor

C. corepressor and activator

D. inhibitor and activator

A. inhibitor and repressor

Which of the following conditions would account for the presence of both the cAMP-CAP complex and allolactose?

A. lactose present, glucose present

B. lactose present, glucose absent

C. lactose absent, glucose present

D. lactose absent, glucose absent

B. lactose present, glucose absent

The hypoxia-inducible factor-1 (HIF-1) can be modulated by

A. phosphorylation and dimerization.

B. binding of a hormone and phosphorylation.

C. binding of a hormone and dimerization.

D. binding of a hormone, phosphorylation, and dimerization.

A. phosphorylation and dimerization.

Which of the following is FALSE regarding the histones of nucleosomes?

A. They bind to the major groove of DNA.

B. They are positively charged.

C. They form an octamer.

D. They can be covalently modified by functional groups.

A. They bind to the major groove of DNA.

Histone acetyltransferases ------ acetyl groups on lysine residues, resulting in a(n) -------- of DNA compaction.

A. add; decrease

B. add; increase

C. remove; increase

D. remove; decrease

A. add; decrease

Which of the following is NOT a mechanism by which DNA methylation of CpG islands inhibits transcription?

A. Preventing the binding of an activator

B. Recruiting HDACs to compact the DNA

C. causing the binding of methyl-CpG-binding proteins

D. All are possible mechanisms

D. All are possible mechanisms.

Expression of both the paternal and maternal H19 genes may be the cause of Silver-Russell syndrome, characterized by the undergrowth of body tissues.

A. Beckwith-Wiedemann syndrome is characterized by the overgrowth of body tissues.

B. Rett syndrome, a neurodevelopmental disorder.

C. Duchenne muscular dystrophy, characterized by progressive muscle degeneration.

A. Beckwith-Wiedemann syndrome is characterized by the overgrowth of body tissues.

If you wanted to determine if two proteins interact, you should use

A. a DNA microarray.

B. in situ hybridization.

C. the yeast two-hybrid system.

D. the chromatin immunoprecipitation (ChIP) assay.

C. The yeast two-hybrid system.

siRNA is ---------- and is ------ by Drosha

A. endogenous; processed

MiRNA

B. endogenous; not processed

C. exogenous; processed

by Drosha.

D. exogenous; not processed

D. exogenous; not processed

If the binding of RISC to mRNA is exactly complementary, then

A. The mRNA is degraded.

B. Translation is inhibited.

C. The result is a gene knockdown.

D. The mRNA is degraded, and the result is a gene knockdown.

E. translation is inhibited, and the result is a gene knockdown

D. The mRNA is degraded, and the result is a gene knockdown.

In the following diagram of the mex-3 experiment, what was injected into the C. elegans embryos in figure C, resulting in the mRNA knockdown pattern shown?

A. mex-3 sense RNA

B mex-3 antisense RNA

C. mex-3 sense and antisense RNA

D. Nothing; this sample was a negative control

B. mex-3 antisense RNA.

In a Western blot, the purpose of adding SDS is to

A. Denature the proteins and coat them with a negative charge.

B. Denature proteins and make them susceptible to antibody binding.

C. Activate the enzyme linked to the 2° antibody.

D. Facilitate the interaction between the 1° antibody and the 2° antibody.

A. to denature the proteins and coat them with a negative charge.

Which of the following about plasmid vectors is TRUE? Plasmid vectors must

A. Have an origin of replication.

B. have a multiple cloning site.

C. Carry a selectable marker for selection.

D. All of the above.

D. All of the above

Which of the following statements is FALSE regarding DNA or its synthesis?

A. The mRNA must be from a prokaryote.

B. The mRNA must contain a poly-A tail.

C. The cDNA contains exons but not introns.

D. The cDNA will have less nucleotides than the gene it was derived from.

A. The mRNA must be from a prokaryote.

The DNA for a eukaryotic gene X is 900 base pairs long. A cDNA clone is used to isolate a genomic clone of gene X, and the gene is sequenced. From start to stop codon, the gene is found to be 1800 base pairs long. The most probable reason for the discrepancy is that

A. The mRNA broke during DNA synthesis.

B. The gene is present as a tandem duplication.

C. The gene has 900 base pairs of introns.

D. The genomic clone is not really gene X, just a related gene.

C. The gene has 900 base pairs of introns.

The drawing below shows the restriction sites of a segment of DNA. E and P refer to locations where EcoRI and PstI cut the DNA, respectively. The restricted sites are numbered 1-

6. Distances between restriction sites are shown on the bottom scale in base pairs (bp). The asterisks represent the part of the DNA that has homology with a probe.

Supposing there was a mutation at site 5, what banding pattern would be present in a Southern blot after digesting the DNA with both EcoRI and Pstl?

A. 2 bands: 4 kb, 7 kb

B. 3 bands: 2 kb, 4 kb, 5 kb

C. 3 bands: 3 kb, 5 kb, 6 kb

D. no bands

B. 3 bands: 2 kb, 4 kb, 5 kb

Suppose you insert a gene of interest (GOI) into a plasmid cloning vector. You then transform E. coli with your cloning vector and plate the cells on media containing ampicillin and X-gal to get the result shown below. The colony on the right is blue.

A. The white colonies contain your GOI because the insertion of the GOI results in a functional B-galactosidase that converts X-gal into a white product.

B. The white colonies contain your GOI because the insertion of the GOI results in a nonfunctional B-galactosidase, so that X-gal cannot be converted into a blue product.

C. The blue colonies contain your GOI because the insertion of the GOI results in a functional β-galactosidase that converts X-gal into a blue product.

D. The blue colonies contain your GOI because the insertion of the GOI results in a nonfunctional -galactosidase, so that X-gal remains blue

B. The white colonies contain your GOI because the insertion of the GOI results in a nonfunctional β-galactosidase, so that X-gal cannot be converted into a blue product.

The following are four processes common to most cloning experiments:

transforming bacteria

plating bacteria on selective medium 4, 3412 cutting DNA with restriction endonucleases 1 ligating DNA fragments Place the components of this list in the order in which they would most likely occur.

A. 3, 4, 1, 2

B. 1, 2, 3, 4

C. 2, 1, 4, 3

C. 3, 4, 1, 2.

It is possible to make DNA from bacterial mRNA.

A. True

B) False

A. True

In quantitative PCR, the more DNA, the ----------- fluorescence.

A. less

B. more

B. more

Expression of -------- promotes X-inactivation.

A. Xist

B. Tsix

C. Xic

A. Xist.

Real-time PCR is also known as

A. RT-PCR.

B. FISH.

C. quantitative PCR.

D. DNA sequencing

C. quantitative PCR

Northern blot and colony hybridization are similar in that they both use

A. bacteria. B. restriction enzymes.

C. Radioactive probes.

D. DNA polymerase

C. Radioactive probes.

Which of the following RNA molecules are involved in RNA interference?

A. miRNA

B. dRNA

C. siRNA

D. All of the above.

D. All of the above.

Which of the following is used in the in vivo method of gene cloning but NOT the in vitro method?

A. ligase

B. dNTPs

C. DNA polymerase

D. All are used in both methods.

A. ligase

After performing a blue-white screening for gene cloning, the technique known as _ will allow you to determine which bacteria have your gene of interest.

A. RT-PCR

B. Southern blot

C. in situ hybridization

D. colony hybridization

D. colony hybridization

Which of the following is NOT used to detect or quantify protein?

A. Western blot

B. immunohistochemistry

C. In situ hybridization

D. immunofluorescence

C. In situ hybridization.

Which of the following is NOT used to detect or quantify nucleic acids?

A. Southern blot

B. Northern blot

C. Western blot

D. RT-PCR

E. real-time PCR

C. western blot

The discovery of RNA interference (RNAi) led to its use in biotechnology and medicine. All of the following are examples of how RNAi could be used in biotechnology or medicine. EXCEPT

A. to treat a disease characterized by the buildup of a specific protein.

B. to treat a disease characterized by the normal expression of a mutated gene.

C. to treat a disease characterized by the overexpression of a nonmutated gene.

D. to treat a disease characterized by a gene that is not expressed

D. to treat a disease characterized by a gene that is not expressed.