Questions from All Exams and Quizzes

Question 1

Which of the following are NOT characteristics of a DNA double helix?

a. nitrogenous bases on the inside of the helix
b. strands antiparallel
c. 25 bases per one turn of the helix
d. A-T base pairs contain two hydrogen bonds, C-G base pairs contain 3 hydrogen bonds

Answer 1

c. 25 bases per one turn of the helix

Question 2

How do purines and pyrimidines differ?

a. pyrimidines have a double ring while purines have a single ring structure
b. purines are the components of RNA; pyrimidines are only found in DNA
c. purines have double ring while pyrimidines have a sing ring structure
d. pyrimidines are only found in RNA; purines are the components of DNA

Answer 2

c. Purines have the double ring while pyrimidines have a single ring structure

Question 3

Which of the following statements about the major groove of double stranded DNA is true?

a. It is narrower than the minor groove.
b. It refers to the space between the sugar and the phosphate on the DNA backbone.
c. It allows proteins to ‘read’ the DNA sequence without disrupting the double helix.
d. All of the statements are correct.
e. None of the statements are correct

Answer 3

c. It allows proteins to ‘read’ the DNA sequence without disrupting the double helix

Question 4

One function of DNA pol I during replication in prokaryotes is to:

a. join the ends of adjacent Okazaki fragments together
b. separate the double-stranded DNA into single-stranded regions
c. replicate the lagging strand of DNA in eukaryotic cells
d. relieve tension induced by supercoiling
e. remove the RNA primers that initiate replication

Answer 4

e. Remove the RNA primers that initiate replication

Question 5

Which of the following is NOT a property of DNA polymerase III?

a. It is responsible for incorporating most of the nucleotides in the leading strand.
b. It contains a 3’ to 5’ proofreading activity.
c. It is responsible for incorporating most of the nucleotides in the lagging strand.
d. It does not require primers to extend the leading strand.
e. It has a very low error rate.

Answer 5

d. It does not require primers to extend the leading strand

Question 6

If the sequence GTGAT mutates to become GTAAT, the G to A alteration is called a:

a. depurination
b. transversion
c. transition
d. tautomeric shift

Answer 6

c. Transition

Question 7

Which of the following is NOT a step in the repair of a deaminated cytosine?

a. N-glycosylase to remove the damages base
b. primase to synthesize an RNA primer
c. apyrimidinic endonuclease to nick the backbone at the damaged base
d. DNA polymerase to add the correct base
e. DNA ligase to seal the nick in the backbone

Answer 7

b. Primase to synthesize an RNA primer

Question 8

Site-directed mutagenesis:

a. can be used to produce a specific allele of a gene
b. can be used to modify the function of a gene
c. can be used to modify the binding site for a repressor in the 5’ untranslated region of a gene
d. can be used to restore a mutant gene back to wild-type sequence
e. all of the above

Answer 8

e. All of the above

Question 9

Restriction enzymes usually only cut foreign viral DNA and ignore their own bacterial DNA. The
reason for this behavior is:
a. their bacterial DNA is methylated
b. transcriptional repression of the restriction enzyme’s structural gene
c. translational modification of the restriction enzyme
d. the heterochromatin state of the bacterial DNA
e. the foreign viral DNA is methylated

Answer 9

a. Their bacterial DNA is methylated

Question 10

The enzyme used in PCR is:

a. DNA ligase
b. a thermostable DNA polymerase
c. reverse transcriptase
d. the restriction endonuclease PvuII
e. the single-stranded binding protein PCNA

Answer 10

b. A thermostable DNA polymerase

Question 11

A tautomeric shift during replication can cause the following type of mutation:
 True / False 11. missense mutation
 True / False 12. repeat tract expansion
 True / False 13. silent mutation
 True / False 14. frameshift mutation
 True / False 15. neutral mutation

Answer 11

True  11. missense mutation
 False 12. repeat tract expansion
 True 13. silent mutation
 False 14. frameshift mutation
 True 15. neutral mutation

Question 12

Which of the following statements about RNA and DNA are true and which are false?
True / False 16. RNA contains ribose rather than deoxyribose sugars
True / False 17. DNA secondary structure is less variable than RNA
True / False 18. RNA polymers incorporate uracil
True / False 19. RNA has a –OH group on the 2’ carbon that DNA lacks
True / False 20. RNA cannot serve as the genetic information storage medium

Answer 12

True 16. RNA contains ribose rather than deoxyribose sugars
True 17. DNA secondary structure is less variable than RNA
True 18. RNA polymers incorporate uracil
True 19. RNA has a –OH group on the 2’ carbon that DNA lacks
False 20. RNA cannot serve as the genetic information storage medium

Question 13

The function of topoisomerases during replication is to:
True / False 21. join the ends of adjacent Okazaki fragments together
True / False 22. separate the DNA strands from each other
True / False 23. relieve tension induced by supercoiling
True / False 24. remove the RNA primers that initiate replication
True / False 25. generate the primer used to initiate synthesis

Answer 13

The function of topoisomerases during replication is to:
False 21. join the ends of adjacent Okazaki fragments together
False 22. separate the DNA strands from each other
True 23. relieve tension induced by supercoiling
False 24. remove the RNA primers that initiate replication
False 25. generate the primer used to initiate synthesis

Question 14

Which repair mechanism acts on an apurinic site?

Answer 14

Base excision repair

Question 15

Which repair mechanism acts on a thymine dimer?

Answer 15

Nucleotide excision repair OR Photolyase

Question 16

Which repair mechanism acts on a T:C base pair in interphase?

Answer 16

Mismatch repair OR DNA Proofreading

Question 17

Which repair mechanism acts on a double-stranded break?

Answer 17

Recombinational repair

Question 18

Which repair mechanism acts on an A:G base pair during DNA synthesis?

Answer 18

DNA Proofreading

Question 19

Which statement about DNA polymerase III is FALSE?

a. It is responsible for incorporating most of the nucleotides in the leading strand.
b. It contains a 3’ to 5’ proofreading activity.
c. It is responsible for incorporating most of the nucleotides in the lagging strand.
d. It does not require primers to extend the leading strand.
e. It has a very low error rate.

Answer 19

d. It does not require primers to extend the leading strand

Question 20

One function of DNA pol I during replication in prokaryotes is to:

a. join the ends of adjacent Okazaki fragments together
b. separate the double-stranded DNA into single-stranded regions
c. replicate the lagging strand of DNA in eukaryotic cells
d. relieve tension induced by supercoiling
e. remove the RNA primers that initiate replication

Answer 20

e. Remove the RNA primers that initiate replication

Question 21

The enzyme used in making cDNA is:

a. DNA ligase
b. a thermostable DNA polymerase
c. reverse transcriptase
d. polynucleotide kinase
e. the single-stranded binding protein PCNA

Answer 21

c. Reverse transcriptase

Question 22

7-methyl-guanosine is added to mRNA molecules during a processing reaction in eukaryotes. The
unique processing event is a:
a. 3’-5’ triphosphate linkage at the 3’ end of the RNA
b. 2’-5’ triphosphate linkage at the 5’ end of the RNA
c. 3’-5’ triphosphate linkage at the 5’ end of the RNA
d. 3’-2’ triphosphate linkage at the 3’ end of the RNA
e. 5’-5’ triphosphate linkage at the 5’ end of the RNA

Answer 22

e. 5’-5’ triphosphate linkage at the 5’ end of the RNA

Question 23

The reduced expression of the lac operon in the presence of glucose is an example of :

a. transcriptional activation
b. catabolite repression
c. operon silencing
d. regulatory dominance
e. anabolic repression

Answer 23

b. Catabolite repression

Question 24

Attenuation at the trp operon in E. coli occurs when:

a. translation and transcription become uncoupled
b. high tryptophan levels inhibit the binding of a repressor protein
c. low tryptophan levels increase the rate of RNA polymerase progression
d. high tryptophan levels allow the formation of a terminator stem-loop in the trpL mRNA
e. the tryptophan membrane transporter increases the rate of tryptophan import

Answer 24

d. High tryptophan levels allow the formation of a terminator stem-loop in the trpL mRNA

Question 25

Which is most commonly found in the P site of ribosomes? a. a tRNA with the growing peptide chain attached b. a tRNA with no amino acid attached c. a tRNA with a single amino acid attached d. ribosome releasing factor e. termination factor

Answer 25

a. A tRNA with the growing peptide chain attached

Question 26

Which statement about the Shine-Delgarno sequence is FALSE? a. it is found near the 5’ end of prokaryotic mRNAs. b. it is complementary to a sequence near the 3’ end of the 16S rRNA. c. it helps position the small ribosomal subunit near the translation start site. d. it contains the AUG initiator codon. e. it is required for efficient translation.

Answer 26

d. It contains the AUG initiator codon

Question 27

Which of the following methods would be used to determine the amino acid sequence of a peptide? a. polymerase chain reaction b. western blotting c. organism cloning d. gel shift assay e. mass spectrometry

Answer 27

e. Mass spectrometry

Question 28

Mass spectrometry can detect all of these EXCEPT: a. proteins that have been post-translationally modified. b. proteins made from mRNAs that have been alternatively spliced. c. proteins made from mRNAs that have used alternate polyadenylation sites. d. proteins present in cancer cells but not in normal cells. e. proteins that have been localized in the wrong cellular compartment.

Answer 28

e. Proteins that have been localized in the wrong cellular compartment.

Question 29

Which of the following types of mutation is likely to have the greatest consequence to the cell? a. a G => A change that creates a stop codon within a gene b. trisomy of an autosome c. an insertion of a T in a homopolymeric run of Ts d. an inversion of the long arm of the X chromosome e. a reciprocal translocation between two autosomes

Answer 29

b. Trisomy of a autosome

Question 30

A scientist suspects that a short translocation has occurred that might involve a gene that she is studying. What is the fastest way to determine if the cells carry the translocation? a. sequence the genome with DNA from the cells b. use PCR to amplify the gene c. use a labeled probe of the gene to do in situ hybridization d. do a chromosome walk with the gene as an initial probe e. construct a YAC library from the cell’s DNA

Answer 30

c. Use a labeled probe of the gene to do in situ hybridization

Question 31

Which statement about RNA interference is FALSE? a. it occurs only in plants. b. it involves short RNAs that are complementary to the target mRNA. c. it can inhibit the transcription of the target mRNA. d. it can cause the degradation of the target mRNA. e. it can inhibit the translation of the target mRNA.

Answer 31

a. It occurs only in plants

Question 32

The function of helicases during replication is to: True / False 14. join the ends of adjacent Okazaki fragments together True / False 15. separate the DNA strands from each other True / False 16. relieve tension induced by supercoiling True / False 17. remove the RNA primers that initiate replication

Answer 32

False 14. join the ends of adjacent Okazaki fragments together True 15. separate the DNA strands from each other False 16. relieve tension induced by supercoiling False 17. remove the RNA primers that initiate replication

Question 33

Microarrays are useful when studying the gene expression in cancer cells because: True / False 18. they can identify all of the genes that are overexpressed. True / False 19. they can identify all of the genes that are underexpressed. True / False 20. they can identify all of the genes that have point mutations.

Answer 33

True 18. they can identify all of the genes that are overexpressed. True 19. they can identify all of the genes that are underexpressed. False 20. they can identify all of the genes that have point mutations.

Question 34

In partially diploid E. coli cells with the genotype F' i+ o- z- y+ a-/ chromosome i- o+ z+ y- a+, which functional gene product(s) would be expressed at high level in the absence of lactose? True / False 27. β-galactosidase only True / False 28. β-galactosidase, permease, and transacetylase True / False 29. permease only True / False 30. permease and transacetylase

Answer 34

False 27. β-galactosidase only False 28. β-galactosidase, permease, and transacetylase True 29. permease only False 30. permease and transacetylase

Question 35

Which of the following statements about nucleotides are true and which are false? True / False 31. The phosphate group is attached to the nitrogenous base. True / False 32. A nucleotide contains a base, a sugar, and a phosphate group. True / False 33. The sugar contains two nitrogen atoms. True / False 34. The nitrogenous base is attached to the sugar by a glycosidic bond.

Answer 35

False 31. The phosphate group is attached to the nitrogenous base. True 32. A nucleotide contains a base, a sugar, and a phosphate group. False 33. The sugar contains two nitrogen atoms. True 34. The nitrogenous base is attached to the sugar by a glycosidic bond.

Question 36

Histone acetyltransferases act to: True / False 35. eliminate the positive charge of lysines in histones True / False 36. increase the compaction of DNA around histones True / False 37. help the histones reassemble following DNA replication True / False 38. prevent the translation of histone mRNA molecules True / False 39. remove covalent modifications on the lysine residues of histones

Answer 36

True 35. eliminate the positive charge of lysines in histones False 36. increase the compaction of DNA around histones False 37. help the histones reassemble following DNA replication False 38. prevent the translation of histone mRNA molecules False 39. remove covalent modifications on the lysine residues of histones

Question 37

During protein synthesis, the tRNA synthetase acts to: True / False 40. attach an amino acid to the anticodon of the tRNA True / False 41. transcribe the genes encoding tRNAs to produce tRNA molecules True / False 42. serve as the first initiation factor during ribosome assembly True / False 43. covalently bind an amino acid to the acceptor stem of the tRNA True / False 44. cause precursor tRNA molecules to adopt their proper final structure

Answer 37

False 40. attach an amino acid to the anticodon of the tRNA False 41. transcribe the genes encoding tRNAs to produce tRNA molecules False 42. serve as the first initiation factor during ribosome assembly True 43. covalently bind an amino acid to the acceptor stem of the tRNA False 44. cause precursor tRNA molecules to adopt their proper final structure

Question 38

``` The following are tRNA binding sites found within ribosomes: True / False 45. peptidyl site True / False 46. exit site True / False 47. elongation site True / False 48. aminoacyl site ```

Answer 38

True 45. peptidyl site True 46. exit site False 47. elongation site True 48. aminoacyl site

Question 39

For which of the following experiments would a DNA microarray be useful? True / False 49. identifying the binding site for a transcription factor True / False 50. determining which genes are induced when a chemical is added to a cell’s growth medium True / False 51. determining which genes are down-regulated in response to heat shock True / False 52. identifying the site of a DNA inversion True / False 53. distinguishing between two closely related bacterial subspecies

Answer 39

True 49. identifying the binding site for a transcription factor True 50. determining which genes are induced when a chemical is added to a cell’s growth medium True 51. determining which genes are down-regulated in response to heat shock False 52. identifying the site of a DNA inversion True 53. distinguishing between two closely related bacterial subspecies

Question 40

URE is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 40

D. Transcription

Question 41

Shine-Dalgarno Sequence is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 41

E. Translation

Question 42

tRNA is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 42

E. Translation

Question 43

Non-Template strand is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 43

D. Transcription

Question 44

AUG codon is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 44

E. Translation

Question 45

Primase is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 45

B. DNA Replication

Question 46

TATA Box is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 46

D. Transcription

Question 47

Splicing is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 47

C. RNA Processing

Question 48

Pribnow Box is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 48

D. Transcription

Question 49

Hemi-methylated DNA is most closely associated with which of the following? a. DNA repair b. DNA replication c. RNA processing d. transcription e. translation

Answer 49

A. DNA Repair

Question 50

In a gene, the DNA strand that has the same sequence of nucleotides as the mRNA transcribed from that gene is known as the ________ strand.

Answer 50

non-template OR sense OR coding

Question 51

The coding sequences in eukaryotic genes that are joined during pre m-RNA splicing are called ________.

Answer 51

Exons

Question 52

Thymine crosslinked dimers in DNA are usually fixed by which repair mechanism?

Answer 52

Nucleotide excision repair

Question 53

A Northern blot is used to detect what type of molecule?

Answer 53

RNA

Question 54

What type of probe(s) is used in a Northern blot?

Answer 54

Nucleic acid: DNA, RNA, oligo, etc

Question 55

A Southern blot is used to detect what type of molecule?

Answer 55

DNA

Question 56

What type of probe(s) is used in a Southern blot?

Answer 56

Nucleic acid: DNA, RNA, oligo, etc

Question 57

A Western blot is used to detect what type of molecule?

Answer 57

Protein

Question 58

What type of probe(s) is used in a Western blot?

Answer 58

Antibody

Question 59

In dideoxy DNA sequencing, which carbons on the sugar portion of the nucleotide lack OH groups?

Answer 59

2' and 3'

Question 60

Which base is not found in DNA? a. adenine b. cytosine c. guanine d. uracil e. thymine

Answer 60

d. Uracil

Question 61

Which statements best describe a nucleotide? (More than one may be correct) a. the phosphate group is attached to the base b. a nucleotide contains a base, a sugar, and a phosphate group c. the sugar contains two nitrogen atoms d. the bases contain extra-cyclic groups such as NH2 or O e. the base is attached to the sugar by a glycosidic bond

Answer 61

b. a nucleotide contains a base, a sugar, and a phosphate group d. the bases contain extra-cyclic groups such as NH2 or O e. the base is attached to the sugar by a glycosidic bond

Question 62

Which are features of a DNA double helix? (More than one may be correct) a. the bases interact by covalent bonding b. the sugar-phosphate backbone is on the outside of the helix c. each base pair contains either two purines or two pyrimidines d. the backbones of the two strands run in opposite directions e. bases are positioned perpendicular to the overall axis of the DNA strand

Answer 62

b. the sugar-phosphate backbone is on the outside of the helix d. the backbones of the two strands run in opposite directions e. bases are positioned perpendicular to the overall axis of the DNA strand

Question 63

Which statements about RNA are false? a. RNA differs from DNA by containing ribose, not deoxyribose sugars b. RNA contains uracil instead of thymine c. RNA secondary structure is more variable than DNA d. none of these statements are false

Answer 63

d. None of these statements are false

Question 64

Which RNA polymerase component is required for promoter recognition? a. alpha (α) b. beta (β) c. beta prime (β’) d. sigma (σ) e. omega (ω)

Answer 64

d. Sigma (σ)

Question 65

Attenuation of the trp operon occurs when: a. the trp repressor binds to the operator b. the corepressor molecules are released from the repressor c. specific stem-loop structures form in the RNA d. the cell lacks charged tryptophan tRNA molecules e. All of these

Answer 65

c. Specific stem-loop structures form in the RNA

Question 66

E. coli DNA replication and transcription are similar in that: a. both use DNA Polymerase III b. both use dNTPs c. both require formation of an open bubble to initiate synthesis d. both require primers to initiate synthesis e. both make copies of each strand during synthesis

Answer 66

c. Both require the formation of an open bubble to initiate synthesis

Question 67

Which of the following is the small effector molecule that binds to CAP (catabolic activator protein)? a. allolactose b. glucose c. tryptophan d. cAMP e. mediator

Answer 67

d. cAMP

Question 68

Separating the double helix into single strands during replication requires which protein? a. DNA polymerase I b. DNA polymerase II c. helicase d. topoisomerase e. primase

Answer 68

c. Helicase

Question 69

Leading and lagging strand synthesis differs in that: a. On the leading strand, synthesis is 5’ to 3’ but 3’ to 5’ on the lagging b. Leading strand synthesis does not require topoisomerase, unlike lagging strand synthesis c. The leading strand requires only a single primer, while the lagging strand requires multiple primers d. Helicases open the leading strand faster than the lagging strand

Answer 69

c. The leading strand requires only a single primer, while the lagging strand requires multiple primers

Question 70

The technique used to determine that DNA replication occurs semi-conservatively was: a. X-ray crystallography b. electron microscopy c. sequencing d. equilibrium density-gradient centrifugation e. microarray analysis

Answer 70

d. Equilibrium density-gradient centrifugation

Question 71

All of the following are properties of DNA polymerase III except: a. It completes synthesis of the leading strand before beginning synthesis of the lagging strand b. It is responsible for incorporating most of the nucleotides in the lagging strand c. It is responsible for incorporating most of the nucleotides in the leading strand d. It contains a 3’ to 5’ proofreading activity e. It has a very low error rate

Answer 71

a. It completes synthesis of the leading strand before beginning synthesis of the lagging strand

Question 72

If the sequence ACATA mutates to become ACTTA, the A to T alteration is called a: a. depurination b. transversion c. transition d. tautomeric shift

Answer 72

b. Transversion

Question 73

Which of these DNA repair mechanisms does not use DNA polymerase during repair? a. homologous recombinational repair of a double-strand break b. base excision repair of an apurinic site c. mitotic mismatch repair d. photolyase repair of a thymine dimer e. nucleotide excision repair of a thymine dimer

Answer 73

d. Photolyase repair of a thymine dimer

Question 74

A tautomeric shift during replication most likely results in a: a. missense mutation b. deletion mutation c. frameshift mutation d. insertion mutation e. inversion mutation

Answer 74

a. Missense mutation

Question 75

Site-directed mutagenesis: a. can be used to restore a mutant gene back to wild-type sequence b. can be used to modify the function of a gene c. can be used to modify the binding site for a repressor in the 5’ untranslated region of a gene d. all of the above e. none of the

Answer 75

d. All of the above

Question 76

Steroids act in transcription regulation by: a. directly binding and activating RNA Polymerase II b. binding to and inactivating repressor proteins c. displacing inhibitor proteins from transcription factors d. binding to a surface receptor that activates a transcription factor e. none of the above

Answer 76

c. Displacing inhibitor proteins from transcription factors

Question 77

Histone acetyltransferases act by: a. adding phosphate groups to serines of histone proteins b. adding acetyl groups to serines of histone proteins c. adding phosphate groups to lysines of histone proteins d. adding acetyl groups to lysines of histone proteins e. moving acetyl groups from histone proteins to transcription factors

Answer 77

d. Adding acetyl groups to lysines of histone proteins

Question 78

Which of the following is not a domain found within transcription factors? a. zinc finger b. basic domain c. cytosine zipper d. helix-turn-helix e. glutamine-rich domain

Answer 78

c. Cytosine zipper

Question 79

A single nucleosome is composed of: a. Eight histone proteins, linker proteins, and about 146 bp of DNA b. Eight histone proteins and about 146 bp of DNA c. Six histone proteins and about 146 bp of DNA d. Four histone proteins and about 146 bp of DNA

Answer 79

b. Eight histone proteins and about 146 bp of DNA

Question 80

Which of the following processing events are not used with prokaryotic tRNAs: a. endonucleolytic cleavage b. exonucleolytic cleavage c. base modifications d. poly-A tailing

Answer 80

d. Poly-A tailing

Question 81

7-methyl-guanosine is added to mRNA molecules during a processing reaction in eukaryotes. The unique processing event is a: a. 3'-5' triphosphate linkage at the 3’ end of the RNA b. 2'-5' triphophate linkage at the 5’ end of the RNA c. 3'-5' triphosphate linkage at the 5’ end of the RNA d. 3'-2' triphosphate linkage at the 3’ end of the RNA e. 5'-5' triphosphate linkage at the 5’ end of the RNA

Answer 81

e. 5'-5' triphosphate linkage at the 5' end of the RNA

Question 82

During splicing in precursor mRNA in mammalian cells, the first RNA cleavage step involves: a. the covalent linkage of the branch site adenine to the 5’ end of the intron b. covalent linkage of the 5’ end of the second exon with the 3’ end of the branch site c. hydrogen bonding of the guanosine at the branch site with the 3’ exon end d. hydrogen bonding of the adenine at the branch site with the 5’ intron e. disulfide bridging of the 5’ and 3’ ends of the intron

Answer 82

a. The covalent linkage of the branch site adenine to the 5' end of the intron

Question 83

Eukaryotic tRNA molecules have a CCA sequence at their 3’ terminus because: a. that sequence is the anticodon sequence b. that sequence is added by a nucleotidyl transferase c. that sequence is a signal sequence for RNA polymerase binding d. that sequence is a termination signal for the RNaseD exonuclease e. that sequence is required for an internal hairpin to form

Answer 83

b. The sequence is added by a nucleotidyl transferase

Question 84

Tandem mass spectrometry can be used to find out: a. the nucleotide sequence of an mRNA b. the nucleotide sequence of a gene c. the amino acid sequence of a protein d. the composition of a multi-protein complex

Answer 84

c. The amino acid sequence of a protein

Question 85

How many different reading frames are present in a DNA sequence? a. one b. two c. three d. six e. none of the above

Answer 85

d. Six

Question 86

A microarray used to study gene expression is hybridized with: a. total RNA from a specific cell type b. protein from a specific cell type c. cDNA from a specific cell type d. PCR-generated oligonucleotides using genomic DNA templates

Answer 86

c. cDNA from a specific cell type

Question 87

``` You are investigating a protein complex, and have isolated one protein and raised antibodies to it. You suspect it interacts directly with another protein. The easiest and fastest way to determine if the interaction does occur is to do a: a. ChIP-chip b. tandem mass spectrometry analysis c. Western blot d. immunoprecipitation e. two-hybrid analysis ```

Answer 87

d. Immunoprecipitation

Question 88

What is the role of sigma factor? a. it recognizes the termination signal b. it stays associated with RNA polymerase at all times c. it recognizes conserved sequences in the promoter d. all these are roles of sigma factor.

Answer 88

c. It recognizes conserved sequences in the promoter

Question 89

In E. coli cells, the level of cyclic AMP is determined by: a. the presence of an F factor
 b. the glucose concentration
 c. the lactose concentration
 d. the allolactose concentration e. the total amount of cellular RNA

Answer 89

b. The glucose concentration

Question 90

E. coli cells that are growing in a medium that is rich in glucose cannot be induced to express the enzyme β-galactosidase, even when lactose is added to the medium. This repression is due to: a. irreversible binding of the lac repressor protein to the operator
 b. failure of the transcription termination mechanism
 c. induction of the lacI gene by glucose
 d. failure of the Catabolite Activator Protein/cyclic AMP complex to bind the lac promoter e. a conformational change in the lac repressor protein due to an interaction with glucose

Answer 90

d. Failure of the Catabolite Activator Protein/cyclic AMP complex to bind the lac promoter

Question 91

Attenuation at the trp operon in E. coli occurs when: a. translation and transcription become uncoupled b. high tryptophan levels inhibit the binding of a repressor protein c. low tryptophan levels increase the rate of RNA polymerase progression d. high tryptophan levels allow the formation of a terminator stem-loop in the trpL mRNA e. the tryptophan membrane transporter increases the rate of tryptophan import

Answer 91

d. High tryptophan levels allow the formation of a terminator stem-loop in the trpL mRNA

Question 92

Which of the following is NOT a common method of gene regulation in eukaryotes? a. histone modification b. attenuation c. nucleosome spacing alterations d. RNA processing

Answer 92

b. Attentuation

Question 93

Which of the following statements is NOT correct? a. the consensus sequence for the eukaryotic polyadenylation signal is AAUAAA b. the typical length of a poly A tail in humans is 200-250 nucleotides c. polyA polymerase adds adenine nucleotides to the 5' end d. polyadenylation is important for the stability of a mRNA e. endonuclease cleavage occurs about 20 nucleotides downstream of the polyadenylation signal

Answer 93

c. polyA polymerase adds adenine nucleotides to the 5' end

Question 94

Which statement about pre-mRNA introns is true? a. They are removed by cutting and joining the DNA b. They are never removed; the ribosome skips them when making protein c. They contain short consensus sequences at both ends d. They are removed after the mRNA has been transported to the cytoplasm e. None of these statements are true

Answer 94

c. They contain short consensus sequences at both ends

Question 95

Which statement about small nuclear ribonucleoprotein particles (snRNPs) is false? a. They contain both RNA and protein components b. They bind to specific sites in the pre-mRNA c. They interact with Group I self-splicing introns d. They interact with each other to form an active spliceosome e. None of these statements are false

Answer 95

c. They interact with Group I self-splicing introns

Question 96

Transcription is similar to DNA replication in that it…. True / False 11. requires a DNA template True / False 12. requires a primer to initiate synthesis True / False 13. begins at specific sites in the genome True / False 14. requires the step-wise formation of a multi-component complex to initiate True / False 15. synthesizes a new strand in the 5’ to 3’ direction

Answer 96

True 11. requires a DNA template False 12. requires a primer to initiate synthesis True 13. begins at specific sites in the genome True 14. requires the step-wise formation of a multi-component complex to initiate True 15. synthesizes a new strand in the 5’ to 3’ direction

Question 97

The following are DNA binding domains used in transcription factors: True / False 16. zinc finger True / False 17. helix-turn-helix True / False 18. basic domain True / False 19. disulfide bridge True / False 20. glutamine-rich domain

Answer 97

``` True 16. zinc finger True 17. helix-turn-helix True 18. basic domain False 19. disulfide bridge False 20. glutamine-rich domain ```

Question 98

Indicate True or False for each statement about the Carboxy Terminal Domain of RNA polymerase II: True / False 21. it is phosphorylated by TFIIH True / False 22. its phosphates are removed when transcription elongation begins True / False 23. capping factors bind when it is dephosphorylated True / False 24. splicing factors bind when it is phosphorylated True / False 25. polyadenylation factors bind when it is phosphorylated

Answer 98

True 21. it is phosphorylated by TFIIH False 22. its phosphates are removed when transcription elongation begins False 23. capping factors bind when it is dephosphorylated True 24. splicing factors bind when it is phosphorylated True 25. polyadenylation factors bind when it is phosphorylated

Question 99

For which of the following experiments would a DNA microarray be useful? True / False 26. identifying the binding site for a transcription factor True / False 27. determining if a transition mutation occurred in a gene during replication True / False 28. determining which genes are down-regulated in response to heat shock True / False 29. identifying the site of a DNA inversion True / False 30. distinguishing between two closely related bacterial subspecies

Answer 99

True 26. identifying the binding site for a transcription factor False 27. determining if a transition mutation occurred in a gene during replication True 28. determining which genes are down-regulated in response to heat shock False 29. identifying the site of a DNA inversion True 30. distinguishing between two closely related bacterial subspecies