5) Which of the following, when taken up by the cell, binds to the repressor so that the repressor no longer binds to the operator?

B) inducer

6) Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation?

inducer

7) A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in

A) continuous transcription of the structural gene controlled by that regulator.

8) The lactose operon is likely to be transcribed when

D) the cyclic AMP and lactose levels are both high within the cell.

9) Transcription of the structural genes in an inducible operon

B) starts when the pathway's substrate is present.

10) For a repressible operon to be transcribed, which of the following must occur?

C) RNA polymerase must bind to the promoter, and the repressor must be inactive.

11) Allolactose, an isomer of lactose, is formed in small amounts from lactose. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when the lactose enters the cell?

B) Allolactose binds to the repressor protein.

12) Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways?

B) Allolactose binds to the repressor protein.

13) In response to chemical signals, prokaryotes can do which of the following?

B) alter the level of production of various enzymes

14) If glucose is available in the environment of E. coli, the cell responds with a very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect to be a measurable effect?

E) increased concentrations of sugars such as arabinose in the cell

15) In positive control of several sugar-metabolism-related operons, the catabolite activator protein (CAP) binds to DNA to stimulate transcription. What causes an increase in CAP?

B) decrease in glucose and increase in cAMP

16) There is a mutation in the repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of these would characterize such a mutant?

C) It cannot bind to the inducer.

17) Which of the following mechanisms is (are) used to coordinate the expression of multiple, related genes in eukaryotic cells?

A) Genes are organized into clusters, with local chromatin structures influencing the expression of all the genes at once.

18) If you were to observe the activity of methylated DNA, you would expect it to

C) have turned off or slowed down the process of transcription.

19) Genomic imprinting, DNA methylation, and histone acetylation are all examples of

D) epigenetic phenomena.

20) When DNA is compacted by histones into 10-nm and 30-nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?

B) methylation and phosphorylation of histone tails

21) Two potential devices that eukaryotic cells use to regulate transcription are

D) DNA methylation and histone modification.

22) During DNA replication,

C) methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication.

23) In eukaryotes, general transcription factors

B) bind to other proteins or to a sequence element within the promoter called the TATA box.

24) Steroid hormones produce their effects in cells by

D) binding to intracellular receptors and promoting transcription of specific genes.

25) Transcription factors in eukaryotes usually have DNA binding domains as well as other domains that are also specific for binding. In general, which of the following would you expect many of them to be able to bind?

D) other transcription factors

26) Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?

C) Eukaryotic exons may be spliced in alternative patterns.

27) Which of the following experimental procedures is most likely to hasten mRNA degradation in a eukaryotic cell?

C) Eukaryotic exons may be spliced in alternative patterns.

28) Which of the following is most likely to have a small protein called ubiquitin attached to it?

A) a cyclin that usually acts in G₁, now that the cell is in G₂

29) In prophase I of meiosis in female Drosophila, studies have shown that there is phosphorylation of an amino acid in the tails of histones of gametes. A mutation in flies that interferes with this process results in sterility. Which of the following is the most likely hypothesis?

D) Histone tail phosphorylation prohibits chromosome condensation.

30) The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called

A) RNA interference.

31) At the beginning of this century there was a general announcement regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes. There was surprise expressed by many that the number of protein-coding sequences was much smaller than they had expected. Which of the following could account for most of the rest?

D) non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function

32) Among the newly discovered small noncoding RNAs, one type reestablishes methylation patterns during gamete formation and block expression of some transposons. These are known as

B) piRNA.

33) Which of the following best describes siRNA?

A) a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA

34) One way scientists hope to use the recent knowledge gained about noncoding RNAs lies with the possibilities for their use in medicine. Of the following scenarios for future research, which would you expect to gain most from RNAs?

C) targeting siRNAs to disable the expression of an allele associated with autosomal dominant disease

35) Which of the following describes the function of an enzyme known as Dicer?

D) It trims small double-stranded RNAs into molecules that can block translation.

36) In a series of experiments, the enzyme Dicer has been inactivated in cells from various vertebrates so that the centromere is abnormally formed from chromatin. Which of the following is most likely to occur?

C) Centromeres will be euchromatic rather than heterochromatic and the cells will soon die in culture.

37) Since Watson and Crick described DNA in 1953, which of the following might best explain why the function of small RNAs is still being explained?

E) Changes in technology as well as our ability to determine how much of the DNA is expressed have now made this possible.

38) You are given an experimental problem involving control of a gene's expression in the embryo of a particular species. One of your first questions is whether the gene's expression is controlled at the level of transcription or translation. Which of the following might best give you an answer?

B) You measure the quantity of the appropriate pre-mRNA in various cell types and find they are all the same.

39) In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. This is due to

A) nonidentical genes that produce different versions of globins during development.

40) The fact that plants can be cloned from somatic cells demonstrates that

A) differentiated cells retain all the genes of the zygote.

41) In animals, embryonic stem cells differ from adult stem cells in that

A) embryonic stem cells are totipotent, and adult stem cells are pluripotent.

42) What is considered to be the first evidence of differentiation in the cells of an embryo?

B) the occurrence of mRNAs for the production of tissue-specific proteins

43) Embryonic lethal mutations result in

D) phenotypes that are never born/hatched.

44) Your brother has just purchased a new plastic model airplane. He places all the parts on the table in approximately the positions in which they will be located when the model is complete. His actions are analogous to which process in development?

E) pattern formation

45) The product of the bicoid gene in Drosophila provides essential information about

E) the anterior-posterior axis.

46) If a Drosophila female has a homozygous mutation for a maternal effect gene,

B) all of her offspring will show the mutant phenotype, regardless of their genotype.

47) Mutations in which of the following genes lead to transformations in the identity of entire body parts?

D) homeotic genes

48) Which of the following genes map out the basic subdivisions along the anterior-posterior axis of the Drosophila embryo?

B) segmentation genes

49) Gap genes and pair-rule genes fall into which of the following categories?

B) segmentation genes

50) The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur?

D) Anterior structures would form in both sides of the embryo.

51) What do gap genes, pair-rule genes, segment polarity genes, and homeotic genes all have in common?

A) Their products act as transcription factors.

52) Which of the following statements describes proto-oncogenes?

D) They can code for proteins associated with cell growth.

53) Which of the following is characteristic of the product of the p53 gene?

A) It is an activator for other genes.

54) Tumor-suppressor genes

C) can encode proteins that promote DNA repair or cell-cell adhesion.

55) BRCA1 and BRCA2 are considered to be tumor-suppressor genes because

B) their normal products participate in repair of DNA damage.

56) The cancer-causing forms of the Ras protein are involved in which of the following processes?

A) relaying a signal from a growth factor receptor

57) Forms of the Ras protein found in tumors usually cause which of the following?

E) growth factor signaling to be hyperactive

58) A genetic test to detect predisposition to cancer would likely examine the APC gene for involvement in which type(s) of cancer?

A) colorectal only

59) At this point, the embryo is characterized as

B) nuclei in the cortex that has not undergone cytokinesis.

60) The four sequestered cells at one end are most probably destined to become

B) the germ cells of the adult.

61) Formation of the pole cells (the four sequestered cells) demonstrates the role of

C) maternal effect genes.

62) The next step after the embryo is formed would be

D) enclosure of the nuclei in membranes, forming a single layer over the surface.

63) The developmental stages described for Drosophila illustrate

A) a hierarchy of gene expression.

64) If she moves the promoter for the lac operon to the region between the beta galactosidase gene and the permease gene, which of the following would be likely?

D) Beta galactosidase will be produced.

65) If she moves the operator to the far end of the operon (past the transacetylase gene), which of the following would likely occur when the cell is exposed to lactose?

D) The structural genes will be transcribed continuously.

66) If she moves the repressor gene (lac I), along with its promoter, to a position at some several thousand base pairs away from its normal position, which will you expect to occur?

E) The lac operon will function normally.

67) If she moves the operator to a position upstream from the promoter, what would occur?

B) The lac operon will be expressed continuously.

68) Which of the following is a likely explanation for the lack of transgene expression in the fifth cell line?

A) A transgene integrated into a heterochromatic region of the genome.

69) Of the lines that express the transgene, one is transcribed but not translated. Which of the following is a likely explanation?

B) no AUG in any frame

70) In one set of experiments using this procedure in Drosophila, she was readily successful in increasing phosphorylation of amino acids adjacent to methylated amino acids in histone tails. Which of the following results would she most likely see?

B) decreased chromatin condensation

71) In one set of experiments she succeeded in decreasing methylation of histone tails. Which of the following results would she most likely see?

A) increased chromatin condensation

72) One of her colleagues suggested she try increased methylation of C nucleotides in a mammalian system. Which of the following results would she most likely see?

E) inactivation of the selected genes

73) She tried decreasing the amount of methylation enzymes in the embryonic stem cells and then allowed the cells to further differentiate. Which of the following results would she most likely see?

C) abnormalities of mouse embryos

74) Within the first quarter hour, the researcher sees that the intact RNA is found in the cells. After 3 hours, she is not surprised to find that

A) Dicer enzyme has reduced it to smaller double-stranded pieces.

75) Some time later, she finds that the introduced strand separates into single-stranded RNAs, one of which is degraded. What does this enable the remaining strand to do?

A) Dicer enzyme has reduced it to smaller double-stranded pieces.

76) In addition, she finds what other evidence of this single-stranded RNA piece's activity?

C) The rate of accumulation of the polypeptide to be translated from the target mRNA is reduced.

77) The researcher in question measures the amount of new polypeptide production in embryos from 2—8 hours following fertilization and the results show a steady and significant rise in polypeptide concentration over that time. The researcher concludes that

C) the resulting new polypeptides are due to translation of maternal mRNAs.

77) The researcher in question measures the amount of new polypeptide production in embryos from 2—8 hours following fertilization and the results show a steady and significant rise in polypeptide concentration over that time. The researcher concludes that

C) Larval features begin to make their appearance.

79) The researcher measures the concentration of the polypeptides from different regions in the early embryo and finds the following pattern (darker shading = greater concentration): SEE IMAGE

`D) The substance is produced in region 1 and diffuses toward region 5.

One hereditary disease in humans, called xeroderma pigmentosum (XP), makes homozygous individuals exceptionally susceptible to UV-induced mutation damage in the cells of exposed tissue, especially skin. Without extraordinary avoidance of sunlight exposure, patients soon succumb to numerous skin cancers.

D) inherited inability to repair UV-induced mutation

81) Given the damage caused by UV, the kind of gene affected in those with XP is one whose product is involved with

C) the ability to excise single-strand damage and replace it.

82) Two children are born from the same parents. Child one inherits a predisposition to retinoblastoma (one of the mutations) and child two does not. However, both children develop the retinoblastoma. Which of the following would you expect?

A) an earlier age of onset in child one

83) In colorectal cancer, several genes must be mutated in order to make a cell a cancer cell, supporting Knudsen's hypothesis. Which of the following kinds of genes would you expect to be mutated?

B) genes involved in control of the cell cycle

84) Knudsen and colleagues also noted that persons with hereditary retinoblastoma that had been treated successfully lived on but then had a higher frequency of developing osteosarcomas (bone cancers) later in life. This provided further evidence of their theory because

D) one of the mutations involved in retinoblastoma is also one of the changes involved in osteosarcoma.

85) One of the human leukemias, called CML (chronic myelogenous leukemia), is associated with a chromosomal translocation between chromosomes 9 and 22 in somatic cells of bone marrow. Which of the following allows CML to provide further evidence of this multistep nature of cancer?

C) The translocation requires breaks in both chromosomes 9 and 22, followed by fusion between the reciprocal pieces.

86) In areas of the world in which malaria is endemic, notably in sub-Saharan Africa, EBV can cause Burkitt's lymphoma in children, which is usually associated with large tumors of the jaw. Which of the following is consistent with these findings?

D) Malarial response of the immune system prevents an individual from making EBV antibodies.

87) In a different part of the world, namely in parts of southeast Asia, the same virus is associated with a different kind of cancer of the throat. Which of the following is most probable?

A) Viral infection is correlated with a different immunological reaction.

88) A very rare human allele of a gene called XLP, or X-linked lymphoproliferative syndrome, causes a small number of people from many different parts of the world to get cancer following even childhood exposure to EBV. Given the previous information, what might be going on?

C) They must be unable to mount an immune response to EBV.

89) What must characterize the XLP population?

C) They must all be males with affected female relatives.

90) If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then

D) the amino acid acts as a corepressor.

91) Muscle cells differ from nerve cells mainly because they

A) express different genes.

92) The functioning of enhancers is an example of

A) transcriptional control of gene expression.

93) Cell differentiation always involves

A) transcriptional control of gene expression.

94) Which of the following is an example of post-transcriptional control of gene expression?

C) the removal of introns and alternative splicing of exons

95) What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

D) continuous transcription of the operon's genes

96) Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror-image duplication of posterior parts. This is evidence that the product of the bicoid gene

C) normally leads to formation of head structures.

97) Which of the following statements about the DNA in one of your brain cells is true?

E) It is the same as the DNA in one of your heart cells.

98) Within a cell, the amount of protein made using a given mRNA molecule depends partly on

B) the rate at which the mRNA is degraded.

99) Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

B) Proto-oncogenes normally help regulate cell division.

e

e

1) Which of the following variations on translation would be most disadvantageous for a cell?

A) translating polypeptides directly from DNA

2) Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because

A) metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies.

3) Garrod's information about the enzyme alteration resulting in alkaptonuria led to further elucidation of the same pathway in humans. Phenylketonuria (PKU) occurs when another enzyme in the pathway is altered or missing, resulting in a failure of phenylalanine (phe) to be metabolized to another amino acid: tyrosine. Tyrosine is an earlier substrate in the pathway altered in alkaptonuria. How might PKU affect the presence or absence of alkaptonuria?

B) It would have no effect, because tyrosine is also available from the diet.

4) The nitrogenous base adenine is found in all members of which group?

C) ATP, RNA, and DNA

5) A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is

A) 3' UCA 5'.

6) The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?

A) A gene from an organism can theoretically be expressed by any other organism.

7) The "universal" genetic code is now known to have exceptions. Evidence for this can be found if which of the following is true?

A) If UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only).

8) Which of the following nucleotide triplets best represents a codon?

D) a triplet in the same reading frame as an upstream AUG

9) Which of the following provides some evidence that RNA probably evolved before DNA?

D) DNA polymerase uses primer, usually made of RNA.

10) Which of the following statements best describes the termination of transcription in prokaryotes?

B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

11) Which of the following does not occur in prokaryotic gene expression, but does in eukaryotic gene expression?

C) A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end.

12) RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism of such sigma switching?

B) It might allow the polymerase to recognize different promoters under certain environmental conditions.

13) Which of the following is a function of a poly-A signal sequence?

B) It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~1035 nucleotides away.

14) In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein?

C) RNA polymerase II

15) Transcription in eukaryotes requires which of the following in addition to RNA polymerase?

D) several transcription factors (TFs)

16) A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which of the following might this illustrate?

C) Any mutation in the sequence is selected against.

17) The TATA sequence is found only several nucleotides away from the start site of transcription. This most probably relates to which of the following?

A) the number of hydrogen bonds between A and T in DNA

18) What is a ribozyme?

B) an RNA with enzymatic activity

19) A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that

A) many noncoding stretches of nucleotides are present in mRNA.

20) During splicing, which molecular component of the spliceosome catalyzes the excision reaction?

C) RNA

21) Alternative RNA splicing

B) can allow the production of proteins of different sizes from a single mRNA.

22) In the structural organization of many eukaryotic genes, individual exons may be related to which of the following?

C) the various domains of the polypeptide product

23) In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after he has removed its 5' cap and poly-A tail. Which of the following would you expect him to find?

D) The molecule is digested by exonucleases since it is no longer protected at the 5' end.

24) Which components of the previous molecule will also be found in mRNA in the cytosol?

C) 5' UTR E₁ E₂ E₃ E₄ UTR 3'

25) When the spliceosome binds to elements of this structure, where can it attach?

E) to the end of an intron

26) Which of the following is a useful feature of introns for this model?

D) Introns allow exon shuffling.

27) Suppose that exposure to a chemical mutagen results in a change in the sequence that alters the 5' end of intron 1 (I₁). What might occur?

D) inclusion of I₁ in the mRNA

28) Suppose that an induced mutation removes most of the 5' end of the 5' UTR. What might result?

B) Removal of the 5' UTR also removes the 5' cap and the mRNA will quickly degrade.

29) A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is

C) UUU.

30) Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the

E) bonding of the anticodon to the codon and the attachment of amino acids to tRNAs.

31) What is the function of GTP in translation?

A) GTP energizes the formation of the initiation complex, using initiation factors.

32) A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that

B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.

33) There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that

B) the rules for base pairing between the third base of a codon and tRNA are flexible.

34) Which of the following is the first event to take place in translation in eukaryotes?

E) the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA

35) Which of the following is a function of a signal peptide?

D) to translocate polypeptides across the ER membrane

36) When translating secretory or membrane proteins, ribosomes are directed to the ER membrane by

B) a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane.

37) An experimenter has altered the 3' end of the tRNA corresponding to the amino acid methionine in such a way as to remove the 3' AC. Which of the following hypotheses describes the most likely result?

C) The amino acid methionine will not bind.

38) The process of translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and which of the following?

B) polypeptide factors plus GTP

39) When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate?

A) an assembled ribosome with a polypeptide attached to the tRNA in the P site

40) What is the function of the release factor (RF)?

B) It binds to the stop codon in the A site in place of a tRNA.

41) When the function of the newly made polypeptide is to be secreted from the cell where it has been made, what must occur?

B) Its signal sequence must target it to the ER, from which it goes to the Golgi.

42) Suppose that a mutation alters the formation of a tRNA such that it still attaches to the same amino acid (phe) but its anticodon loop has the sequence AAU that binds to the mRNA codon UUA (that usually specifies leucine leu).

C) One mutated tRNA molecule will be relatively inconsequential because it will compete with many "normal" ones.

43) Why might a point mutation in DNA make a difference in the level of protein's activity?

D) It might substitute an amino acid in the active site.

44) In the 1920s Muller discovered that X-rays caused mutation in Drosophila. In a related series of experiments in the 1940s, Charlotte Auerbach discovered that chemicals–she used nitrogen mustards–have a similar effect. A new chemical food additive is developed by a cereal manufacturer. Why do we test for its ability to induce mutation?

D) We want to prevent any increase in mutation frequency.

45) Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?

B) a deletion of two nucleotides

46) What is the effect of a nonsense mutation in a gene?

C) It introduces a premature stop codon into the mRNA.

47) A frameshift mutation could result from

E) either an insertion or a deletion of a base.

48) Which of the following DNA mutations is the most likely to be damaging to the protein it specifies?

A) a base-pair deletion

49) Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?

B) a base deletion near the start of a gene

50) The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in

D) a polypeptide missing an amino acid.

51) Which of the following mutations is most likely to cause a phenotypic change?

D) a single nucleotide deletion in an exon coding for an active site

52) If a protein is coded for by a single gene and this protein has six clearly defined domains, which number of exons below is the gene likely to have?

C) 8

53) Which of the following statements is true about protein synthesis in prokaryotes?

B) Translation can begin while transcription is still in progress.

54) Of the following, which is the most current description of a gene?

C) a DNA sequence that is expressed to form a functional product: either RNA or polypeptide

55) Gene expression in the domain Archaea in part resembles that of bacteria and in part that of the domain Eukarya. In which way is it most like the domain Eukarya?

A) Domain Archaea have numerous transcription factors.

56) Which of the following is true of transcription in domain Archaea?

C) It is roughly simultaneous with translation.

57) In comparing DNA replication with RNA transcription in the same cell, which of the following is true only of replication?

E) The entire template molecule is represented in the product.

58) In order for a eukaryotic gene to be engineered into a bacterial colony to be expressed, what must be included in addition to the coding exons of the gene?

C) a bacterial promoter sequence

59) When the genome of a particular species is said to include 20,000 protein-coding regions, what does this imply?

D) There are also genes for RNAs other than mRNA.

60) According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

C) 2

61) A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?

A) an accumulation of A and no production of B and C

62) If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding enzyme A would be able to grow on which of the following media?

C) minimal medium supplemented with nutrient B only

63) If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme B would be capable of growing on which of the following media?

D) minimal medium supplemented with C only

64) A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be

E) 3' AAA-GAA-TAA-CAA 5'.

65) What amino acid sequence will be generated, based on the following mRNA codon sequence?

D) met-ser-ser-leu-ser-leu

66) A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?

C) 5' TTT-CCC-AAA-GGG-TTT-CCC

67) Given the locally unwound double strand above, in which direction does the RNA polymerase move?

A) 3' → 5' along the template strand

68) In the transcription event of the previous DNA, where would the promoter be located?

B) to the right of the template strand

69) The dipeptide that will form will be

B) proline-threonine.

70) The anticodon loop of the first tRNA that will complement this mRNA is

A) 3' GGC 5'

71) What type of bonding is responsible for maintaining the shape of the tRNA molecule?

C) hydrogen bonding between base pairs

72) The figure represents tRNA that recognizes and binds a particular amino acid (in this instance, phenylalanine). Which codon on the mRNA strand codes for this amino acid?

D) UUC

73) The tRNA shown in the figure has its 3' end projecting beyond its 5' end. What will occur at this 3' end?

B) The amino acid binds covalently.

74) You add polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine triphosphate. How many artificial mRNA 3 nucleotide codons would be possible?

C) 8

75) You add polynucleotide phosphorylase to a solution of ATP, GTP, and UTP. How many artificial mRNA 3 nucleotide codons would be possible?

D) 27

76) Where does tRNA #2 move to after this bonding of lysine to the polypeptide?

C) E site

77) Which component of the complex described enters the exit tunnel through the large subunit of the ribosome?

D) newly formed polypeptide

78) In eukaryotic cells, transcription cannot begin until

B) several transcription factors have bound to the promoter.

79) Which of the following is not true of a codon?

D) It extends from one end of a tRNA molecule.

80) The anticodon of a particular tRNA molecule is

A) complementary to the corresponding mRNA codon.

81) Which of the following is not true of RNA processing?

A) Exons are cut out before mRNA leaves the nucleus.

82) Which component is not directly involved in translation?

B) DNA

83) Which of the following mutations would be most likely to have a harmful effect on an organism?

E) a single nucleotide insertion downstream of, and close to, the start of the coding sequence