Reference no: EM131051932

Remember to read all of the possible answers for each question before choosing the BEST ANSWER.

1. The first gene was mapped to a specific chromosome by:

a. Mendel.
b. Thomas Morgan.
c. Emil Krebs.
d. Walther Flemming.
e. Alfred Sturtevant.

2. A character [phenotype] is said to be multifactoral. In the context of modern genetics this means that:

a. the locus that controls the character exhibits more than two alleles.
b. the expression of an allele at one locus is affecting the expression of the alleles at another locus.
c. the character/phenotype is influenced by both genetic and environmental factors.
d. it is expressed equally in both males and females.
e. the protein which controls the phenotype has multiple subunits, such as hemoglobin.

3. The first genetic map denoting the relative locations of specific genes on a single chromosome was constructed by:

a. Mendel.
b. Thomas Morgan.
c. Emil Krebs.
d. Walther Flemming.
e. Alfred Sturtevant.

4. A protein that binds to the DNA encoding a bacterial operon, and thus prevents RNA polymerase from transcribing the genes, would be most likely classified as a/an:

a. repressor.
b. CAP protein.
c. operator.
d. transcription factor.
e. post-transcriptional regulator.

5. The experiments that clearly showed that DNA from every organism studied had an amount of adenine equal to the amount of thymine and a cytosine content equal to the content of guanine were conducted by:

a. E. M. Sutton.
b. Cohen and Boyer.
c. Hershey and Chase.
d. Erwin Chargaff.
e. Rosalind Franklin.

6. Which of the following properties are not true in the context of the presently accepted model for DNA structure:

a. DNA is a helical molecule.
b. Two strands of molecule are held to each other by hydrogen bonds.
c. The two strands of the molecule are described as running parallel to each other.
d. Nucleotides are connected to each other by phosphodiester bonds.
e. All of the above statements are true of the presently accepted model for the structure of DNA molecules.

7. In the presence of relatively high levels of tryptophan, transcription of the E. coli trp operon would be:

a. fully on to provide the enzymes to effectively use tryptophan as a carbon source.
b. completely off.
c. expressed normally because the operon is expressed in a constitutive fashion.
d. expressed normally because the enzymes encoded by this operon are all controlled allosterically at the post expression level.
e. likely to be relatively low unless cAMP levels are also elevated.

8. Splicesomes are involved in:

a. translation.
b. DNA replication.
c. prokaryotic transcription.
d. eukaryotic RNA processing.
e. posttranslational modification of polypeptides.

9. The experiments which used DNase, RNase, protease, lipase and cell-free extracts of S. pneumoniae (or Pneumococcus if you prefer) to show that DNA was the genetic material were carried out by:

a. Watson and Crick.
b. Erwin Chargaff.
c. Frederick Griffith.
d. Avery, McCarty and MacLeod.
e. Messelson and Stahl.

10. The portion of a tRNA that interacts with an mRNA while in the ribosome is called the:

a. anticodon.
b. 3' terminus.
c. codon.
d. acceptor terminus.
e. D loop.

11. The genetic code as we now know it is said to have all of the properties given below EXCEPT:

a. triplet.
b. non-overlapping.
c. universal (or nearly so).
d. degenerate.
e. All of the above are properties of the genetic code..

12. When ATP levels fall in an E. coli cell due to a lack of suitable carbon molecules to catabolize, the cell responds by:

a. releasing ubiquitin.
b. activating all available operons encoding catabolic pathways.
c. synthesizing cAMP.
d. releasing calcium into the cytoplasm.
e. making additional general transcription factors.

13. RNAi describes one or more strategies to:

a. splice RNA transcripts.
b. repair damaged genes.
c. inhibit gene expression in higher eukaryotes.
d. introduce the original introns into early genes.
e. clone eukaryotic genes into bacterial cells.

14. The individual(s) who obtained the high quality X-ray diffraction photographs, using crystals of DNA, that was essential of working out the structure of the DNA molecule was/were:

a. Watson and Crick.
b. Cohen and Boyer.
c. Hershey and Chase.
d. Erwin Chargaff.
e. Rosalind Franklin.

15. The semiconservative nature of DNA replication was demonstrated by Messelson and Stahl using:

a. Drosophila melanogaster.
b. E. coli, 14N, 15N, CsCl and an ultracentrifuge.
c. E. coli, 35S, 32P, T2 bacteriophage and a Waring blender.
d. two strains of Pneumococcus.
e. electron microscopy.

16. The RNA molecule which is first released from a eukaryotic gene during the process of transcription is best described as:

a. a monocistronic mRNA.
b. a polycistronic mRNA..
c. an intron.
d. a primary transcript.
e. an exon.

17. The initiation codon for nearly all protein encoding sequences in mRNAs is:

a. AUG.
b. UGA.
c. AUA.
d. UAA.
e. UAG.

18. The E. coli lac operon is best described as being:

a. repressible.
b. constitutive.
c. inducible.
d. All of the above are correct, depending upon the glucose, lactose and galactose concentrations.
e. None of the above is correct answers.

19. The first amino acid utilized in the synthesis of nearly all proteins is:

a. lysine.
b. tryptophan.
c. arginine.
d. glycine.
e. methionine.

20. The E. coli enzyme which synthesizes most of a new DNA strand during replication is:

a. DNA polymerase I.
b. DNA polymerase III.
c. primase.
d. DNA gyrase.
e. DNA ligase.

21. During the process of DNA replication in E. coli, the enzyme primase:

a. connects short segments of DNA together.
b. connects the first few nucleotides of each new molecule.
c. Opens the helix at the replication fork.
d. removes the "over winding" caused by the opening of the DNA helix.
e. binds to single-stranded regions at the fork to keep them from reforming base pairs.

22. Immediately after a new peptide bond is formed in the ribosome, the growing polypeptide chain is attached to:

a. a tRNA in the "P" site.
b. peptidyl synthetase.
c. a tRNA in the "A" site.
d. elongation factor 2.
e. a tRNA in the "E" site.

23. The two strands of a DNA helix are initially separated during the process of DNA replication by:

a. DNA polymerase I.
b. DNA polymerase III.
c. a topoisomerase.
d. primase.
e. helicase.

24. Some bacterial genes are expressed in a constitutive fashion. An example of a group of genes that would be expected to be expressed in this fashion would be:

a. the genes for repressors.
b. the genes encoding catabolic pathways.
c. the genes encoding anabolic pathways.
d. All of the above would be expected to be expressed constitutively.
e. None of the above is a correct answer.

25. The "new" aminoacyl tRNA (charged tRNA) enters the ribosome via the:

a. "P" site.
b. peptidyl transferase.
c. "A" site.
d. elongation site.
e. "E" site.

26. Anabolic operons (operons that encode anabolic pathways such as the trp operon) are commonly regulated by:

a. a repressor protein and the pathway's substrate.
b. a repressor protein and the pathway's product.
c. CAP protein.
d. Answers "a" and "c" are both correct.
e. Answers "b" and "c" are both correct.

27. You are suffering from diphtheria and your cells are dying. The primary problem that is leading to the death of your cells is that they can no longer:

a. replicate their DNA.
b. carry out transcription.
c. properly splice RNA transcripts.
d. regulate gene expression.
e. carry out protein synthesis.

28. At an early stage of development, individual cells become committed to a particular pathway of specialized development, but do not at this time express the proteins required for carrying out the function(s) of the specialized cells their progeny will become. These "committed" cells have undergone the process we call [be sure and choose the most specific answer here]:

a. blastulation.
b. gastrulation.
c. determination.
d. apoptosis.
e. differentiation.

29. DNA synthesis in all organisms occurs:

a. in the 5' to 3' direction..
b. in the 3' to 5' direction..
c. in the 5' to 3' direction on the leading strand but in the 3' to 5' direction on the lagging strand.
d. in the 3' to 5' direction on the leading strand but in the 5' to 3' direction on the lagging strand.
e. at night.

30. Extensive methylation of cytosine bases (in the dinucleotide sequence CG) in a human gene would suggest that the gene is:

a. turned on at a high level.
b. protected from human nucleases.
c. packaged into nucleosomes like other active chromatin.
d. undergoing replication.
e. transcriptionally inactive (turned off) and will likely remain inactive.

31. The enzyme involved in DNA replication which uses ATP as an energy source to remove excess torque in the duplex (over winding or supercoiling) is:

a. DNA ligase.
b. helicase.
c. Ssb.
d. gyrase.
e. DNA polymerase I.

32. Genes of multicellular eukaryotic genomes, essential to normal development and other processes, which when/if "appropriately" mutated can act to promote uncontrolled cell division in a dominant fashion are often:

a. tumor suppressors.
b. proto-oncogenes.
c. oncogenes.
d. cyclins.
e. p53s.

33. Eukaryotic mRNAs nearly always have what at their 5'termini?

a. polyA.
b. AUG.
c. a Cap structure..
d. UAA.
e. TATA.

34. An allele at one locus affects several phenotypic traits (e.g. cystic fibrosis is caused by a single defective gene which causes clogged blood vessels, sticky mucus, salty sweat, liver failure, etc.). This is an example of:

a. continuous variation.
b. codominance.
c. incomplete dominance
d. epistasis.
e. pleiotropic effects.

35. Primer removal by a DNA polymerase during the process of DNA replication requires:

a. a 5'phosphorylase activity.
b. a 5'exonuclease activity.
c. a 3' topoisomerase activity.
d. a 3'exonuclease activity.
e. a 5' helicase activity.

36. The correct model of the structure of a DNA molecule was first elucidated by:

a. Franklin and Wilkins.
b. Linus Pauling.
c. Hershey and Chase.
d. Erwin Chargaff.
e. Watson and Crick.

37. A single nucleotide is added into the coding region of an E. coli gene that encodes Beta-galactosidase. This would like be called:

a. an insertion.
b. a frame-shift mutation.
c. a point mutation.
d. All of the above answers are correct.
e. Answers "a"-"c" are all incorrect.

38. The majority of the genes that are associated with an inherited increased risk of cancer are:

a. an oncogene.
b. a protooncogene.
c. found in viruses.
d. tumor suppressors.
e. Ras proteins.

39. The relatively recent hypothesis that proposes that specific combinations of chromosomal protein modifications, as well as the order in which they have occurred, helps determine chromatin structure/configuration (e.g. remodeling) and this in turn influences gene expression is often referred to as:

a. the histone code hypothesis.
b. the central dogma of gene expression.
c. the transcriptome genesis theory.
d. the rule of histone acetylation.
e. the phosphorylation-acetylation hypothesis.

40. The in the context of the trp operon of E. coli, tryptophan is:

a. an inducer.
b. a repressor.
c. a substrate.
d. apositive regulator.
e. a corepressor.

41. The inheritance of traits transmitted by mechanism not directly involving the nucleotide sequence of DNA molecules is called:

a. linkage effects.
b. maternal inheritance.
c. epigenetic inheritance.
d. Mendelian inheritance, as is all inheritance involving nuclear DNA/chromatin.
e. posttranscriptional regulation.

42. Control elements in the "promoter region" of a eukaryotic gene are commonly bound by:

a. restriction enzymes.
b. protein kinases.
c. topoisomerases.
d. transcription factors.
e. enhancers.

43. The "lagging strand" at a replication fork is made in a series of smaller fragments commonly called:

a. transcriptomes.
b. primers.
c. replisomes.
d. origins.
e. Okazaki fragments.

44. RNA synthesis as carried out by an RNA polymerase is always in the _____ direction.

a. N-terminal to C-terminal
b. G to A.
c. 3' to 5'.
d. 5' to 3'.
e. It occurs in two potential directions, depending upon the strand of the duplex and the direction of the gene being expressed.

45. In 1973 an experiment was performed where the gene encoding amphibian rRNA was spliced into a plasmid and transferred to an E. coli cell, creating the first man made recombinant DNA molecule. This experiment was carried out by:

a. Kary Mullis.
b. Cohen and Boyer.
c. Bruce Ames.
d. Peyton Rous.
e. E. M. Southern.

46. From the perspective of molecular biology, a promoter is BEST described as:

a. developmental regulator.
b. where ribosomes bind to an mRNA.
c. an initiator of apoptosis.
d. an initiator of metamorphosis.
e. the location on DNA where the RNA polymerase binds.

47. The tumor suppressor gene that has been found to be lost or inactivated in more that 50% of all human cancers encodes:

a. a G protein.
b. p53.
c. Rb.
d. a cyclic dependent kinase.
e. No such gene exists since cancers all involve a unique set of mutated genes.

48. An intron-free copy of a eukaryotic mRNA in a DNA form is called a/an:

a. transposon.
b. exon.
c. recombinant DNA molecule.
d. RFLP
e. cDNA.

49. An enzyme is isolated that is found to cut DNA, but only if the target DNA molecule has the sequence GAATTC. This enzyme is likely an example of a/an:

a. restriction endonuclease.
b. DNA ligase.
c. helicase.
d. ribonuclease H.
e. reverse transcriptase.

50. A group of bacterial genes are expressed as a single expression unit and are encoded by a single mRNA. These genes are likely to be part of a/an:

a. regulon.
b. alternative splicing unit.
c. operon.
d. monocistronic unit.
e. multigenic response element.

51. The protein that binds to the control region of the lac operon and increases the level of the operon's expression is called:

a. the lac repressor.
b. the operator.
c. CAP.
d. The aporepressor.
e. the initiation factor.

52. An example of a eukaryotic DNA element to which proteins can bind and activate a gene or genes located up to 1000's of nucleotides upstream or downstream from the element is called:

a. a promoter.
b. an operator.
c. a transcription factor.
d. a methylation site.
e. an enhancer.

53. The specific location where the repressor protein that regulates an operon binds is called the:

a. promoter.
b. terminator.
c. telomere.
d. operator.
e. represson.

54. You have a very small amount of biological evidence (i.e. DNA) left at the scene of a violent crime. You would like to perform a genetic analysis of this evidence but it would seem that there might not be enough to successfully analyze. The forensic DNA tech assures you there will be no problem with a very small amount of sample because the test they perform will incorporate the process of _____ into the procedure (which will amplify the genetic material in the sample by a hundred million fold...).

a. PCR.
b. hybridization.
c. restriction analysis.
d. reverse transcription.
e. microarray analysis.