Complete Test Bank Ch.8 Gene Expression DNA to Protein

Genetics, 6e (Hartwell)

Chapter 8 Gene Expression: The Flow of Information from DNA to RNA to Protein

1) The Central Dogma describes the flow of genetic information as

A) Protein—RNA—DNA.

B) DNA—RNA—Protein.

C) RNA—DNA—Protein.

D) DNA—Protein—RNA.

2) The cellular organelle responsible for protein synthesis is the

A) nucleus.

B) mitochondria.

C) centrioles.

D) ribosome.

3) A codon is a three-base sequence of

A) mRNA that codes for an amino acid.

B) rRNA that codes for an amino acid.

C) tRNA that codes for an amino acid.

D) mRNA or tRNA that codes for an amino acid.

4) Which of these statements does NOT describe a characteristic of the genetic code?

A) The number of codons and amino acids is the same.

B) The code is used by nearly every living organism.

C) Some amino acids have multiple codons.

D) The code is degenerate.

5) Charles Yanofsky helped decipher the genetic code working with the ________ biosynthesis genes in ________.

A) leucine; Salmonella enteritidis

B) phenylalanine; Klebsiella pneumoniae

C) tryptophan; Escherichia coli

D) glycine; Serratia marcescens

6) The DNA sequence 5' ATGCCTGAATCAGCTTTA 3' could encode a maximum of  ____ amino acids in a protein.

A) 5

B) 6

C) 7

D) 18

7) How many different amino acids could be encoded by the synthetic mRNA sequence 5' UGCUGCUGC 3'?

A) 0

B) 1

C) 2

D) 3

E) 6

8) The genetic code includes

A) 3 start codons and 1 stop codon.

B) 2 start codons and 2 stop codons.

C) 1 start codon and 3 stop codons.

D) 0 start codons and 4 stop codons.

9) The pattern or sequence in which a molecule of mRNA is deciphered by a ribosome is the

A) synthesis platform.

B) code degeneration.

C) peptide transition.

D) reading frame.

10) Which of these terms is NOT used as a nickname for a stop codon?

A) emerald

B) amber

C) opal

D) ochre

11) Nonsense codons are

A) codons that code for multiple amino acids.

B) codons that do not code for an amino acid.

C) codons that can be read forward or backward.

D) start codons.

12) Which of these is NOT a step in transcription?

A) replication

B) initiation

C) termination

D) elongation

13) During maturation of a eukaryotic mRNA, sequences that are spliced out are

A) extremes.

B) exons.

C) inclusions.

D) introns.

E) spliceosomes.

14) The sequences found in a mature eukaryotic mRNAs are

A) extremes.

B) exons.

C) inclusions.

D) introns.

E) spliceosomes.

15) The retroviruses, including HIV, are unique because they use

A) replication.

B) reverse transcription.

C) splicing.

D) reverse translation.

E) posttranslational modification.

16) A complex of proteins and small nuclear RNAs that form discrete particles to mediate splicing is a

A) holoenzyme.

B) spliceosome.

C) nucleosome.

D) ribosome.

E) chromosome.

17) RNA molecules that act as enzymes to catalyze specific biochemical reactions are

A) RNases.

B) splice acceptors.

C) ribozymes.

D) tRNAs.

E) restriction enzymes.

18) Experiments that are done outside a living cell are described by the Latin term

A) in vino.

B) in vito.

C) in vivo.

D) in vitro.

19) Experiments that are done inside a living cell are described by the Latin term

A) in vino.

B) in vito.

C) in vivo.

D) in vitro.

20) Transcription occurs ________ and translation occurs ________ of eukaryotic cells.

A) in the nucleus; in the cytoplasm

B) in the cytoplasm; in the nucleus

C) in the nucleus; at the cell membrane

D) in the cytoplasm; at the cell membrane

21) Transcription occurs ________ and translation occurs  ________ of prokaryotic cells.

A) at the cell membrane; in the cytoplasm

B) in the cytoplasm; in the nucleus

C) in the cytoplasm; at the cell membrane

D) in the cytoplasm; in the cytoplasm

22) Select the statement that describes the stability of DNA and RNA under typical cellular conditions.

A) Double-stranded DNA in the nucleus and single-stranded RNA in the cytoplasm are equally stable.

B) Double-stranded DNA in the nucleus is more stable than single-stranded RNA in the cytoplasm.

C) Single-stranded RNA in the cytoplasm is more stable than double-stranded DNA in the nucleus.

D) Both RNA in the cytoplasm and double-stranded DNA in the nucleus can never be degraded within a cell.

23) In the modification of eukaryotic mRNA, ________ cap and ________ tail are usually added to the transcript.

A) an acetylated-guanine; a poly-cytosine

B) a poly-guanine; a methyl group

C) a poly-thymine; an acetyl group

D) a methylated-guanine; a poly-adenine

E) a methylated-adenine; a poly-guanine

24) RNA polymerase binds to ________ before beginning transcription.

A) a promoter

B) an operator

C) a structural gene

D) a replication origin

E) the Shine-Dalgarno

25) A prokaryotic large ribosomal subunit is composed of

A) tRNA and protein.

B) mRNA and protein.

C) rRNA and protein.

D) only proteins folded together.

E) only rRNAs folded together.

26) Aminoacyl-tRNA synthetase is the enzyme that

A) folds tRNA molecules into their proper configuration.

B) causes tRNA molecules to bind to the aminoacyl site of a ribosome.

C) produces tRNA by reading DNA molecules.

D) adds the appropriate amino acid to an uncharged tRNA.

27) Which enzyme forms peptide bonds between adjacent amino acids during polypeptide synthesis?

A) RNA polymerase

B) phosphotransferase

C) peptidyl transferase

D) ribonuclease

28) An anticodon is a physical component of ________ molecule.

A) a tRNA

B) an mRNA

C) an rRNA

D) a DNA

29) Which of these processes are coupled in prokaryotes but NOT in eukaryotes?

A) transcription and translation

B) replication and transcription

C) replication and translation

D) transcription and splicing

30) A mutation that is characterized by a change in the DNA sequence, but no change in the resulting protein sequence, is a

A) frameshift mutation.

B) missense mutation.

C) silent mutation.

D) nonsense mutation.

31) A mutation that changes a codon sequence, and subsequently changes the amino acid that should have been placed at that point in the polypeptide chain, is a

A) frameshift mutation.

B) missense mutation.

C) silent mutation.

D) nonsense mutation.

32) A mutation that changes a codon that originally coded for an amino acid into a stop codon is a

A) frameshift mutation.

B) missense mutation.

C) silent mutation.

D) nonsense mutation.

33) A mutation that occurs when a base is inserted into or deleted from a DNA sequence, completely altering the subsequent sequence of codons, is a

A) frameshift mutation.

B) missense mutation.

C) silent mutation.

D) nonsense mutation.

34) Drugs like AZT, ddC, or ddI work against the AIDS virus because they

A) destroy viral proteins.

B) look like hairpins to cause premature termination of viral mRNA.

C) look like tRNAs and block viral translation.

D) look like nitrogenous bases and block viral reverse transcriptase.

E) prevent the virus from releasing its genome into the cytoplasm.

35) A mutant tRNA that recognizes a nonsense codon and inserts an amino acid where protein synthesis should have stopped is a(n)

A) nonsense tRNA.

B) nonsense suppressor tRNA.

C) revertant tRNA.

D) uncharged tRNA.

36) The ________ codon is used as the start codon by nearly all organisms.

A) AUG methionine

B) UGA arginine

C) AUG cysteine

D) UGA methionine

37) Mutations that completely abolish the function of a wild-type allele are

A) null mutations.

B) hypomorphic mutations.

C) hypermorphic mutations.

D) conditional mutations.

E) neomorphic mutations.

38) Mutations that result in the production of much less of a protein or a protein that functions less efficiently than wild type are

A) null mutations.

B) hypomorphic mutations.

C) hypermorphic mutations.

D) conditional mutations.

E) neomorphic mutations.

39) A neomorphic mutation could result in an allele that

A) produces no gene product.

B) produces a nonfunctional gene product.

C) produces a novel protein that gives rise to a new phenotype.

D) produces mutant protein subunits that aggregate with wild-type subunits, inactivating them.

E) produces an altered protein that functions more efficiently than the wild-type protein does.

40) The appearance of a novel phenotype resulting from the substitution of a single base pair might be due to

A) a change in the amino acid sequence.

B) a change in the amount of protein expressed.

C) an alteration in a gene that codes for a nontranslated RNA.

D) a change in the developmental time or location at which a gene is expressed.

E) All of the choices are possible consequences of a single base pair substitution.

41) A mutation creates a dominant negative allele of a particular gene. The gene encodes a protein that forms a trimer within the cell. If one or more of the subunits has the mutant structure, the entire trimeric protein is inactive. In a heterozygous cell, if the proteins of both alleles are present at the same levels, what percent of the trimers present in the cell will be active?

A) 100%

B) 87.5%

C) 50%

D) 33%

E) 12.5%

42) A neomorphic mutation in the Antennapedia (Antp) gene of Drosophila causes

A) kinks to form in their tails.

B) growth of antenna from the leg region.

C) total loss of color vision.

D) extra antenna on the head.

E) growth of a leg from the head region.

43) In the digestive system, some protease enzymes must be secreted as an inactive form and then activated later by proteolytic cleavage once outside of the secreting cell to prevent active proteases from damaging the secreting cells. What is the category of precursor proteins of this type?

A) ubiquitins

B) zymogens

C) glycosides

D) activins

44) Which of the following is required for initiation of eukaryotic translation?

A) Shine-Dalgarno sequence

B) 5' cap

C) release factors

D) N-formylmethionine

E) introns

45) The DNA sequence 5′ ATGGGGGACACC 3′ encodes the amino acids Met Gly Asp Thr. A mutation changes the sequence to 5′ ATGGGTGACACC 3′, but the same amino acids are encoded. What type of mutation has occurred?

A) frameshift mutation

B) missense mutation

C) silent mutation

D) nonsense mutation

46) The DNA sequence 5′ ATGGGGGACACC 3′ encodes the amino acids Met Gly Asp Thr. A mutation changes the sequence to 5′ ATGGGGAACACC 3′ that encodes the amino acids Met Gly Asn Thr. What type of mutation has occurred?

A) frameshift mutation

B) missense mutation

C) silent mutation

D) nonsense mutation

47) A DNA sequence 5′ ATGGGGGACACC 3′ encodes the amino acids Met Gly Asp Thr. A mutation changes the sequence to 5′ ATGAGGGGACACC 3′ that encodes the amino acids Met Arg Gly His. What type of mutation has occurred?

A) frameshift mutation

B) missense mutation

C) silent mutation

D) nonsense mutation

48) A mutant allele results in a truncated form of a signaling protein. This protein can still bind its receptor protein but does not activate the receptor and inhibits wild-type signaling proteins from binding the receptor. What type of allele is this mutant allele?

A) hypomorphic allele

B) hypermorphic allele

C) neomorphic allele

D) antimorphic allele

49) Many cancers have a mutation that changes a valine to a glutamic acid in the RAF kinase protein which phosphorylates proteins that promote cell division. This mutant protein is a constitutively active kinase. What type of allele is this mutant allele?

A) hypomorphic allele

B) hypermorphic allele

C) null allele

D) antimorphic allele

50) A large deletion removes the promoter and first three exons of a gene. No mRNA or protein is detected. What type of allele is this mutant allele?

A) hypomorphic allele

B) hypermorphic allele

C) null allele

D) antimorphic allele

51) Which of the following mutant alleles is most likely to be dominant to the wild-type allele?

A) a silent mutation

B) a premature stop codon that results in a partial loss of protein function

C) a missense mutation that increases enzyme activity

D) a promoter mutation that reduces gene transcription

52) An anticodon of sequence 5′ GUA 3′ will recognize the codon sequence

A) 5′ GTA 3′.

B) 5′ UAC 3′.

C) 5′ CAU 3′.

D) 5′ AUG 3′.

E) None of the codon sequences are correct.

53) An anticodon of sequence 5′ GUA 3′ will recognize the codon sequence

A) 5′ GTA 3′.

B) 5′ UAU 3′.

C) 5′ CAU 3′.

D) 5′ AUG 3′.

E) None of the codon sequences are correct.

54) A tRNA with the anticodon sequence 5′ IUA 3′ will not normally exist because

A) 5′ UAA 3′ is a stop codon.

B) I is not a base present in tRNAs.

C) it will recognize codons for different amino acids.

D) 5′ UAU 3′ and 5′ UAC 3′ both specify tyrosine.

55) A tRNA with the anticodon sequence 5′ IUC 3′ will not normally exist because

A) 5′ GAU 3′ and 5′ GAC 3′ specify asparagine, but 5′ GAA 3′ specifies glutamic acid.

B) 5′ GAU 3′ and 5′ GAC 3′ specify different amino acids.

C) I is not a base present in tRNAs.

D) 5′ GAU 3′ and 5′ GAC 3′ both specify asparagine.

56) When the anticodon of a tRNA and the codon of an mRNA interact, the two sequences are

A) identical.

B) antiparallel.

C) parallel.

D) not related.

57) The different tRNAs are produced by

A) different aminoacyl-tRNA synthetases that produce tRNAs from ribonucleotides in the cytoplasm.

B) RNA editing of transcripts of a single tRNA gene.

C) alternatively spliced of a single tRNA gene.

D) transcription of different tRNA genes in the genome.

58) The wobble base of a tRNA is

A) the 5′ base of the anticodon.

B) the 3′ base of the anticodon.

C) the 5′ base of the codon.

D) any base in the anticodon.