Genetics Chapter 17 Multiple Choice

21. Which of the following statements about response elements is INCORRECT? a. A single eukaryotic gene is regulated by only one unique response element. b. Response elements are composed of specific consensus sequences that are unique from one another. c. Different genes can possess a common regulatory element upstream of their start site. d. Multiple response elements allow the same gene to be activated by different stimuli. e. Response elements allow complex biochemical responses in eukaryotic cells.

a. A single eukaryotic gene is regulated by only one unique response element.

2. Which of the following statements about histone and gene expression is correct? a. In a general sense, highly condensed DNA bound with histone proteins represses gene expression. b. Acetylation involves the addition of acetyl groups to histone proteins, and it usually results in repression of transcription. c. Addition of methyl groups to the tails of histone proteins always results in activation of transcription. d. Histone code is referring to the modification that takes place on the globular domain of the octomeric histone core. e. All statements above are correct.

a. In a general sense, highly condensed DNA bound with histone proteins represses gene expression.

5. When regions around genes become sensitive to the enzyme DNase I, this is an indication that those regions are a. becoming transcriptionally active. b. becoming more condensed. c. binding to the single-strand binding proteins. d. destabilizing and transcriptionally inactive. e. becoming highly methylated by a methylase.

a. becoming transcriptionally active.

19. Insulators can block the effects of enhancers only when they lie a. between an enhancer and a promoter. b. upstream of a promoter. c. adjacent to a promoter. d. within the structural genes. e. within a consensus sequence.

a. between an enhancer and a promoter.

14. A boundary element is also known as a(n) a. insulator. b. repressor. c. enhancer. d. coactivator. e. mediator.

a. insulator.

29. RITS consists of a. siRNAs and proteins. b. miRNAs and proteins. c. RISCs and mRNAs. d. methyl groups and histone proteins. e. DNA, histone proteins, and mRNAs.

a. siRNAs and proteins.

25. In which part of the mRNA does degradation generally begin? a. At the 5′ end with the removal of the poly(A) tail b. At the 5′ end with the removal of the methyl cap c. At the 3′ end with the removal of the poly(A) tail d. At the 3′ end with the removal of the methyl cap e. Removal from either end is equally likely.

b. At the 5′ end with the removal of the methyl cap

1. Which of the following statements about regulation of the eukaryotic gene expression is INCORRECT? a. The presence of a nuclear membrane separating transcription and translation in eukaryotes led to the evolution of additional mechanisms of gene regulation. b. In eukaryotes, most structural genes are found within operons. c. Eukaryotic mRNAs are generally more stable than prokaryotic mRNAs. d. The rate of degradation of mRNAs is important in regulation in eukaryotes. e. Post-translational regulation of histones is unique to the eukaryotes.

b. In eukaryotes, most structural genes are found within operons.

6. What is the consequence of methylation of DNA sequence called CpG islands? a. Active transcription b. Transcription repression c. Recruitment of chromosome remodeling complex d. Transcriptional stalling e. Insulator sequence formation

b. Transcription repression

4. Proteins that affect the structure of DNA bound to histones without altering histone chemical structure are called a. RISCs. b. chromatin-remodeling complexes. c. splicing complexes. d. MRE activator proteins. e. Dicers.

b. chromatin-remodeling complexes.

28. Regulation of gene expression using siRNAs is found in a. prokaryotes only. b. eukaryotes only. c. prokaryotes and eukaryotes.

b. eukaryotes only.

31. When siRNAs are present, the rate of mRNA degradation ________ and the rate of protein production ____________. a. increases; increases b. increases; decreases c. decreases; decreases d. decreases; increases e. stays constant; decreases

b. increases; decreases

26. Alternative splicing is known to be important in the regulation of the a. production of heat-shock elements. b. mammalian SV40 virus. c. lac operon in E. coli. d. metallothionein gene. e. None of the above

b. mammalian SV40 virus.

7. Which of the following events is known to make DNA to become more sensitive to digestion by DNase I? a. DNA methylation b. Deacetylation of histone c. Acetylation of histone d. Formation of heterochromatin e. All of the above

c. Acetylation of histone

11. In Arabidopsis, FLD (a deacetylase enzyme) stimulates flowering. Which of the following is TRUE? a. FLD deacetylates histones that bind to regions of FLC gene and stimulates its transcription. b. FLD deaceylates histones surrounding FLD gene, causing suppression of FLD transcription. c. FLD deacetylates histones that bind to FLC gene, causing repression of FLC transcription. d. FLD causes repression of FLC translation.

c. FLD deacetylates histones that bind to FLC gene, causing repression of FLC transcription.

18. A mutation in the gene for the yeast regulatory protein GAL4 causes yeast to grow poorly on galactose. What is the function of GAL4? a. It is a substrate that binds and activates a transcriptional activator. b. It is a product that binds and activates a transcriptional repressor. c. It is a transcription activator for the galactose-digesting enzyme gene. d. It is a transcription repressor that prevents expression of yeast galactose-digesting enzymes. e. It is an enzyme that metabolizes galactose.

c. It is a transcription activator for the galactose-digesting enzyme gene.

10. Which of the following statements about CpG islands is correct? a. CpG islands are commonly found at the 3′ UTR regions. b. The CpG island methylation is universal across both prokaryotes and eukaryotes. c. Methylated CpG islands is associated with long term gene repression. d. Transcriptionally active DNA has higher frequency of methylated CpG. e. There is an association exists between DNA methylation at the CpG island and acetylation of histone via recruitment of acetylases.

c. Methylated CpG islands is associated with long term gene repression.

17. Choose the type of control illustrated by GAL4 in the control of genes for yeast galactose-metabolizing enzymes. a. Negative inducible b. Negative repressible c. Positive inducible d. Positive repressible

c. Positive inducible

32. Which of the mechanisms involving siRNA- and miRNA-based gene regulation is INCORRECT? a. Cleavage of mRNA b. Inhibition of translation c. Post-translational modification d. Degradation of mRNA e. Transcriptional silencing

c. Post-translational modification

24. What type of cellular activity is known to occur within P bodies? a. Active transcription b. Active translation c. RNA degradation d. Transcriptional stalling e. DNA hypermethylation

c. RNA degradation

16. Although operons are not common in eukaryotes, eukaryotic genes may be activated by the same stimulus. Which of the following DNA regulatory sequence makes this coordinated gene expression possible? a. Core promoter b. Enhancer element c. Response element d. Boundary element e. Silencer element

c. Response element

23. Degradation of a eukaryotic mRNA is generally initiated by a. cleavage of the 5′ end. b. random cleavages throughout the mRNA strand. c. shortening of poly(A) tail. d. recruitment of chromosome remodeling complex. e. removal of the 5′ cap.

c. shortening of poly(A) tail.

9. Choose the correct order of procedure in performing chromatin immunoprecipitation (ChIP). 1. DNA sequencing and fragment identification 2. Removal of crosslinking and separation of DNA and proteins 3. Crosslinking proteins and chromosomes via UV 4. Antibody incubation for immunoprecipitation 5. Protein degradation via proteases 6. Cell lysis and chromosome fragmentation a. 1, 3, 2, 4, 5, 6 b. 2, 6, 5, 1, 3, 4 c. 4, 3, 2, 5, 1, 5 d. 3, 6, 4, 2, 5, 1 e. 5, 1, 3, 6, 4, 2

d. 3, 6, 4, 2, 5, 1

20. Which of the following eukaryotic gene regulatory mechanisms acts after transcription has been initiated? a. Changes in chromatin structure b. Changes in transcription regulatory proteins c. Assembly of basal transcription apparatus d. Factors that increase RNA polymerase stalling e. Association of transcriptional coactivators

d. Factors that increase RNA polymerase stalling

12. Which of the following facts about eukaryotic gene regulation is TRUE? a. Transcriptional activator proteins bind to the DNA in non specific manner. b. Eukaryotic enhancers are a part of basal transcription apparatus. c. The eukaryotic regulatory promoters are highly conserved with the same consensus sequences throughout the genome. d. Mediators are protein complexes involved in regulating transcription rates. e. The transcriptional repressors always bind to the insulator elements.

d. Mediators are protein complexes involved in regulating transcription rates.

3. Which of the following molecules is capable of targeting chromatin remodeling complexes to specific DNA sequences to modify chromatin structure and activate gene expression? a. Transcriptional repressor b. Enhancer c. DNAse I d. Transcriptional activators e. Histone deacetylase

d. Transcriptional activators

30. siRNAs and miRNAs are produced by the a. cleavage of RISCs by endonucleases. b. cleavage of functional mRNA within the cytoplasm. c. cleavage of pre-mRNA in the nucleus. d. cutting and processing of double-stranded RNA by Dicer enzymes. e. cutting and processing of double-stranded RNA by Slicer enzymes.

d. cutting and processing of double-stranded RNA by Dicer enzymes.

15. A eukaryotic DNA sequence that affects transcription at distant promoters is called a(n) a. insulator. b. silencer. c. mediator. d. enhancer. e. repressor.

d. enhancer.

33. After translation, eukaryotic proteins can be modified by a. acetylation. b. the addition of phosphate groups. c. the removal of amino acids. d. the addition of methyl groups. e. All of the above

e. All of the above

8. Which of the following is NOT addressed by performing chromatin immunoprecipitation (ChIP) technique? a. The types of modification done on the DNA-binding proteins b. The location of modified histones that activate or repress transcription c. The position of transcription factors and associated regulators on the chromosome d. Identification of active promoters on genome-wide level e. All of the above

e. All of the above

13. Which of the following terms is least relevant to the assembly of basal transcription apparatus for transcription? a. Core promoter b. General transcription factors c. TATA box d. RNA polymerase. e. Enhancer

e. Enhancer

27. Which of the following process is also known as RNA silencing and post-transcriptional gene silencing? a. Protein degradation b. Transcriptional stalling c. RNA splicing d. Transcriptional repression e. RNA interference

e. RNA interference

22. mRNAs are degraded by enzymes called a. DNAse I. b. ribozymes. c. heat-shock proteins. d. silencers. e. ribonucleases.

e. ribonucleases.