Bio Ch 25
70)Which of the following serve to directly accelerate the cell cycle? A) tumor-suppressor genes B) carcinogens C) repressors D) oncogenes E) p53 gene
D) oncogenes
6)The X-ray diffraction photography of Rosalind Franklin and Maurice Wilkins was critical to showing that A) DNA has a double-helix structure. B) the bases of DNA were held together by hydrogen bonds. C) DNA has equal numbers of purines and pyrimidines. D) DNA has deoxyribose sugar rather than ribose sugar. E) the four bases of DNA are adenine, guanine, cytosine, and thymine.
A) DNA has a double-helix structure.
44)Which of the following is a true statement about the genetic code? A) The genetic code is composed of triplet codes. B) The genetic code produces 32 different possibilities of codon sequences. C) Each amino acid is coded for by only one codon.D) The genetic code contains start but not stop codons. E) The genetic code contains stop but not start codons.
A) The genetic code is composed of triplet codes.
25)The function of transfer RNA is to A) carry amino acids to ribosomes. B) transfer nucleotides to the nucleus. C) transmit coded information to the cytoplasm. D) turn DNA on and off. E) act as the site for protein synthesis.
A) carry amino acids to ribosomes.
9)Chargaff's rules of DNA structure states that A) A + T = G + C. B) A = T, C = G C) A = C, T = G. D) A = G, T = C. E) the number of purines in DNA never equals the number of pyrimidines.
B) A = T, C = G
31)Which of the following describes the flow of information in protein synthesis? A) protein → RNA → DNA B) DNA → RNA → protein C) DNA → protein → RNA D) RNA → DNA → protein E) RNA → protein → DNA
B) DNA → RNA → protein
63)What are transcription factors? A) Transcription factors are proteins that help the repressor bind to the operator. B) Transcription factors are proteins that help RNA polymerase bind to the promoter. C) Transcription factors are proteins that help DNA polymerase bind to the promoter. D) Transcription factors are proteins that help helicases bind to the operator. E) Transcription factors are proteins that help the operator bind to the repressor.
B) Transcription factors are proteins that help RNA polymerase bind to the promoter.
72)An oncogene is A) a viral gene with no relation to the host cell's genes. B) a mutated form of a proto-oncogene. C) a bacterial gene that causes cancer in the host. D) always seen in human cancer cells. E) a gene that turns off cellular reproduction.
B) a mutated form of a proto-oncogene.
36)What part of the mRNA contain(s) the information for the structure of the protein? A) introns B) exons C) promoter D) ribosomes E) nucleoli
B) exons
71)Tumor-suppressor genes are A) oncogenes that code for proteins that inhibit cell division. B) genes that code for proteins that inhibit cell division. C) oncogenes that code for proteins that stimulate cell division. D) anti-oncogenes that code for proteins that stimulate cell division. E) transposons thatcan be used as cancer therapy.
B) genes that code for proteins that inhibit cell division.
26)Which of the following is part of DNA replication but not gene expression? A) transcription B) lagging strand C) translation D) amino acids E) protein synthesis
B) lagging strand
37)The addition of a poly-A tail to mRNA occurs after which of the following? A) replication B) transcription C) translation D) translocation E) termination
B) transcription
28)Which of the classes of RNA molecules has an anticodon? A) ribosomal RNA B) transfer RNA C) messenger RNA D) primary mRNA transcript E) ribozyme
B) transfer RNA
55)The function of the regulator gene is to A) code for enzymes in a metabolic pathway. B) serve as an on/off switch for transcription. C) code for a repressor molecule that can bind to the operator. D) bind to the RNA polymerase molecule. E) bind to the promoter.
C) code for a repressor molecule that can bind to the operator.
27)Which type of RNA carries the genetic information from the nucleus to the ribosome? A) ribosomal RNA B) transfer RNA C) messenger RNA D) All types of RNA can carry the information from the nucleus to the ribosome.
C) messenger RNA
41)Messenger RNA is produced in the A) cytoplasm. B) ribosomes. C) nucleus. D) endoplasmic reticulum. E) lysosome.
C) nucleus.
3)If the protein coat of a virus that infects a bacterium is labeled with radioactive sulfur while the DNA of the virus is labeled with radioactive phosphorus, over time A) both the sulfur and the phosphorus will be found within the bacterium. B) only the sulfur will be found inside the bacterium.C) only the phosphorus will be found inside the bacterium. D) both the sulfur and the phosphorus will be found outside the bacterium. E) the radioactivity of the sulfur and phosphorus will decay very quickly and not be detectable.
C) only the phosphorus will be found inside the bacterium.
57)Sometimes a newly folded protein must be modified before becoming functional. What level of gene control is this? A) transcriptional B) posttranscriptional C) translational D) posttranslational E) operon
D) posttranslational
13)In the Watson-Crick model of DNA, the "sides" of the ladder are composed of A) sugars. B) bases. C) hydrogen bonds. D) sugar-phosphate molecules. E) phosphate groups.
D) sugar-phosphate molecules.
62)Which level of primary control in eukaryotic gene activity involves using differences in the poly-A tail or the guanine cap to determine how long a particular transcript remains active before it is destroyed? A) pretranscriptional control B) transcriptional control C) posttranscriptional control D) translational control E) posttranslational control
D) translational control
23)Which of the following nucleotide bases is found only in RNA? A) guanine B) adenine C) thymine D) uracil E) cytosine
D) uracil
22)Which of the following is true about DNA? A) transfers messages to the ribosomes B) contains the sugar ribose C) contains adenine, guanine, uracil, and cytosine D) is single stranded E) forms a helix
E) forms a helix
48)The correct sequence of events in the production of a polypeptide is A) initiation → termination → elongation. B) elongation → termination → initiation. C) termination → elongation → initiation. D) elongation → initiation → termination. E) initiation → elongation → termination.
E) initiation → elongation → termination.
16)The enzyme that is used to join DNA nucleotides together is A) DNA polymerase. B) RNA polymerase. C) helicase. D) primase. E) lipase.
A) DNA polymerase.
2)The hereditary material found in all cells is A) DNA. B) rRNA. C) mRNA. D) tRNA. E) ATP.
A) DNA.
52)Specific DNA sequences that have the ability to move within and out of chromosomes are called A) transposons. B) introns. C) exons. D) operators. E) ribozymes.
A) transposons.
58)Which of the following describes pretranscriptional control in eukaryotes? A) Controlling gene expression in the cytoplasm, after mRNA leaves the nucleus but before protein is produced. B) Controlling gene expression in the nucleus, based on which genes are transcribed and how fast they are transcribed. C) Controlling gene expression in the nucleus, after DNA is transcribed, including the speed with which mRNA leaves the nucleus. D) Controlling gene expression in the cytoplasm, after protein synthesis occurs. E) Controlling gene expression by turning on and off genes, through methylation and chromatin packing.
E) Controlling gene expression by turning on and off genes, through methylation and chromatin packing.
14)Which of the following is true about RNA? A) The structure is a double helix. B) The bases are held together by hydrogen bonds.C) The bases are complementary to each other. D) It contains deoxyribose sugar. E) It is composed of the nucleotides adenine, guanine, cytosine, and uracil.
E) It is composed of the nucleotides adenine, guanine, cytosine, and uracil.
65)Which of the following is true about cancer cells? A) They exhibit slow controlled growth. B) They cause malignant tumors only. C) They exhibit highly organized growth. D) They rarely undergo metastasis. E) They are genetically unstable.
E) They are genetically unstable.
12)A nucleotide contains A) DNA and RNA. B) a sugar and a phosphate. C) complementary purines and pyrimidines. D) RNA, protein, and lipids. E) a sugar, a phosphate, and a nitrogen-containing base.
E) a sugar, a phosphate, and a nitrogen-containing base.
46)What part of a tRNA molecule will base pair with the codon of a mRNA molecule? A) DNA sequence B) anticodon C) amino acid binding site D) amino acid E) promoter site
B) anticodon
66)Apoptosis refers to cell death and A) is always biologically detrimental to an organism.B) can be programmed and is essential to normal development. C) is the accumulation of genetic errors. D) is a failure in the translation or transcription mechanism. E) is any failure of the genetic machinery to work correctly.
B) can be programmed and is essential to normal development.
49)The site of translation is the A) nucleus. B) nucleolus. C) ribosome. D) ribozyme. E) mitochondria.
C) ribosome.
24)Which of the following bases pairs with adenine in DNA? A) guanine B) adenine C) thymine D) uracil E) cytosine
C) thymine
51)Which of the following is a point mutation of the nucleotide sequence CATTATCCC? A) CATTTCCC B) CATTAGTCCC C) CTTATCCC D) CATTATCGGGCC E) CATTATCGC
E) CATTATCGC
67)DNA segments at the ends of chromosomes that shorten every time a cell divides are called A) transposons. B) mutagens. C) activated chromatin. D) operons. E) telomeres.
E) telomeres.
1)Which of the following is associated with cancer? A) It can establish new tumors distant from the site of the primary tumor. B) It forms new blood vessels and brings nutrients and oxygen to the tumor. C) Cancer cells can undergo cell division repeatedly and indefinitely. D) Tumors invade surrounding tissues and are filtered by lymph nodes. E) Cancer cells rarely escape the signals for cell death.
A) It can establish new tumors distant from the site of the primary tumor. B) It forms new blood vessels and brings nutrients and oxygen to the tumor. C) Cancer cells can undergo cell division repeatedly and indefinitely. D) Tumors invade surrounding tissues and are filtered by lymph nodes.
69)Which of the following is true about oncogenes? A) Oncogenes are normal genes that have undergone a mutation. B) Oncogenes cause cell division to slow down. C) When mutated, oncogenes turn into proto-oncogenes. D) Oncogenes increase apoptosis in surrounding cells.
A) Oncogenes are normal genes that have undergone a mutation.
7)The individual(s) given the most credit for the discovery of the structure of DNA is (are) A) Alfred Hershey and Martha Chase. B) James Watson and Francis Crick. C) Erwin Chargaff. D) Rosalind Franklin and Maurice Wilkins. E) Charles Darwin and Gregor Mendel.
B) James Watson and Francis Crick.
35)A sequence of mRNA that is removed during processing is a(n) A) exon. B) intron. C) replicon. D) promoter. E) gene.
B) intron.
45)Which part of a mRNA molecule is edited out? A) exons. B) introns. C) transposons. D) inducers. E) promoters.
B) introns.
19)In semiconservative DNA replication, each new double helix formed will have A) two new strandsand two old strands. B) one new and one old strand in each helix. C) three new strands in one helix and three old strands in the second helix. D) two new and one old strand in one helix and two old and one new strand in the second helix. E) two new strands in one helix and two old strands in the other helix.
B) one new and one old strand in each helix.
17)Because every DNA molecule contains one old strand and one new strand, the process of DNA replication is called A) conservative. B) semiconservative. C) mixed. D) dispersive.
B) semiconservative.
15)Which of the following statements about DNA replication is correct? A) As hydrogen bonds break, the DNA molecule reforms its helical structure. B) The process is known as conservative replication because both old strands are conserved in one daughter DNA molecule and two new strands comprise the other daughter DNA molecule. C) The enzyme that catalyzes DNA replication is DNA polymerase. D) Complementary base pairs are held together with covalent bonds. E) Only the leading strand utilizes the enzyme helicase.
C) The enzyme that catalyzes DNA replication is DNA polymerase.
68)When the sheep Dolly was successfully cloned, it was produced by growing an in vitro fertilized egg where the normal egg nucleus had been removed and replaced by a nucleus from an adult. Since this nucleus was from an older mature animal, which of the following would be a reasonable expectation? A) The nucleus from the older mature animal would have additional Barr bodies. B) The nucleus from the older mature animal would contain DNA with many mutations. C) The nucleus from the older mature animal would contain chromosomes with shorter telomeres. D) The nucleus from the older mature animal would have chromosomes with longer telomeres. E) The nucleus from the older mature animal would have a higher concentration of mRNA.
C) The nucleus from the older mature animal would contain chromosomes with shorter telomeres.
54)Two strains of E. coli—one of which can turn on its lactase production and one that cannot—are grown together with lactose in the medium. If all other conditions are equal, what will occur? A) Both strains will continue to be present in equal amounts. B) The two strains will kill each other off. C) The strain that can turn on lactase production will outcompete the other strain. D) The strain that cannot turn on lactase production will outcompete the other strain. E) The two strains will work cooperatively and share the lactose.
C) The strain that can turn on lactase production will outcompete the other strain.
60)Which level of primary control in eukaryotic gene activity involves the speed of transport of mRNA from the nucleus into the cytoplasm? A) pretranscriptional B) transcriptional control C) posttranscriptional control D) translational control E) posttranslational control
C) posttranscriptional control
77)A cell of the pancreas specializes in producing insulin, while a muscle cell specializes in the production of the protein myosin. This means that A) the pancreas and muscle cells are both actively using the genes for insulin and myosin. B) the pancreas cells are actively using the insulin gene, while the muscle cells are actively using both the insulin and myosin genes. C) the pancreas cells are actively using the gene that produces insulin, while muscle cells are actively using the gene that produces myosin. D) neither the pancreas cells nor the muscle cells are specialized. E) only muscle cells can produce proteins.
C) the pancreas cells are actively using the gene that produces insulin, while muscle cells are actively using the gene that produces myosin.
11)In DNA, the amount of adenine is always equal to the amount of A) cytosine. B) uracil. C) guanine. D) thymine. E) ATP.
D) thymine.
64)Which of the following proteins speed up transcription dramatically? A) repressors B) RNA polymerases C) promoters D) transcription activators E) DNA polymerases
D) transcription activators
18)Which of the following describes a function of DNA helicase? A) connects the Okazaki fragments and seals any breaks in the sugar-phosphate backbone B) adds nucleotides to the growing 3' end of the new DNA strand C) creates the lagging strand in semiconservative replication D) unwinds and "unzips" the double-stranded DNA by breaking the weak hydrogen bonds between the paired bases E) re-creates the broken hydrogen bonds so that DNA becomes double-stranded again
D) unwinds and "unzips" the double-stranded DNA by breaking the weak hydrogen bonds between the paired bases
10)If a species contains 23% A in its DNA, what is the percentage of guanine it would contain? A) 23% B) 46% C) 25% D) 44% E) 27%
E) 27%
78)Which of the following factors is likely to a mutation and possibly cancer? A) X-rays B) ultravioletradiation C) cigarette smoke D) pesticides E) All of the answer choices can lead to cancer.
E) All of the answer choices can lead to cancer.
74)Which of the following behaviors would put you at the greatest risk of developing cancer? A) avoiding carcinogenic chemicals B) avoiding excessive sunlight C) lowering total fat intake D) increasing your consumption of broccoli E) applying pesticides to your home and garden without proper protection
E) applying pesticides to your home and garden without proper protection
43)Which of the following processes takes place during transcription? A) attachment of a ribosome to mRNA B) growth of a polypeptide chain C) binding of two tRNA molecules/ribosome D) liberation of polypeptide from ribosome E) production of mRNA
E) production of mRNA
42)Which is most directly responsible for the sequence of amino acids in a protein? A) the sequence of the anticodons B) the number of codons in mRNA C) the enzyme that attaches the amino acid to tRNAD) the proteins associated with rRNA E) the sequence of codons in mRNA
E) the sequence of codons in mRNA
73)Which of the following is associated with a lower cancer risk? A) hormone therapy B) smoking C) use ofalcohol D) exposure to certain hazardous chemicals in the workplace E) using sunscreen or sunblock.
E) using sunscreen or sunblock.
39)Which of the following is involved in both transcription and translation? A) mRNA B) tRNA C) rRNA D) ribosome E) mRNA, rRNA, and tRNA
A) mRNA
61)Which level of primary control in eukaryotic gene activity involves methylation and chromatin packing as a way to keep genes turned off? A) pretranscriptional control B) transcriptional control C) posttranscriptional control D) translationalcontrol E) posttranslational control
A) pretranscriptional control
29)Which of the classes of RNA molecules is produced in the nucleolus? A) ribosomal RNA B) transfer RNA C) messenger RNA D) primary mRNAtranscript E) ribozymes
A) ribosomal RNA
38)Which is the process by which a protein is constructed in the cytoplasm of eukaryotic cells? A) translation B) transcription C) replication D) transformation E) translocation
A) translation
33)If one strand of DNA has the base sequence 5'AAGCAA3', the complementary strand has which of the following sequences? A) 3'UUCGUU5' B) 3'TTCGTT5' C) 3'AAGCAA5' D) 3'UTCGTU5' E) 3'TTCGTG5'
B) 3'TTCGTT5'
32)Transcription of part of a DNA molecule with a nucleotide sequence of 3' AAACAACTT 5' results in a mRNA molecule with the complementary sequence of A) 5' GGGAGAACC 3'. B) 5' UUUGUUGAA 3'. C) 5' TTTGAAGCC 3'. D) 5' CCCACCTCC 3'. E) 5' AAACAACTT 3'.
B) 5' UUUGUUGAA 3'.
47)Initiation, elongation, and termination are three stages in A) DNA replication. B) error correction by proofreading enzymes. C) mRNAprocessing. D) translation. E) intron removal.
D) translation.
40)How many bases on a DNA molecule equal one codon? A) 1 B) 2 C) 3 D) 4 E) 20
C) 3
21)A gene is physically located on a(n) A) chromosome. B) transfer RNA. C) enzyme. D) protein. E) nucleus.
A) chromosome.
56)Active genes are found in the A) heterochromatin. B) euchromatin. C) Barr bodies. D) promoters. E) operons.
B) euchromatin.
30)Prior to protein synthesis, the DNA A) attracts tRNAs with appropriate amino acids. B) serves as a template for the production of mRNA.C) adheres to ribosomes for protein synthesis. D) contains anticodons that become codons. E) must first undergo replication.
B) serves as a template for the production of mRNA.
20)During semiconservative replication, if the parental strand has adenine, which of the following bases will be placed on the new strand? A) adenine B) thymine C) cytosine D) guanine E) uracil
B) thymine
75)A cluster of prokaryotic genes under the control of one regulatory sequence is called a(n) A) repressor. B) promoter. C) operon. D) operator. E) regulator gene.
C) operon.
59)Which of the following levels of control involves the use of a poly-A tail? A) pretranscriptional B) transcriptional C) posttranscriptional D) transcriptional control E) translational
C) posttranscriptional
8)The fact that for a given species the amount of purines in the DNA always matches the number of pyrimidines was first determined by A) Watson and Crick. B) Franklin and Wilkins. C) Hershey and Chase. D) Chargaff. E) Mendel.
D) Chargaff.
34)During the process of transcription, the information in A) a protein is converted into RNA. B) RNA is converted into a protein. C) RNA is converted into DNA. D) DNA is converted into RNA. E) DNA is converted into a protein.
D) DNA is converted into RNA.
5)Which scientist(s) is/are noted for their X-ray diffraction photo of DNA? A) Chargaff B) Griffith C) Messelson and Stahl D) Franklin E) Hershey and Chase
D) Franklin
53)Which of the following occurs when lactose is present in the environment of E. coli? A) Thelac repressor binds to the promoter. B) RNA polymerase binds to the operator. C) No genes are transcribed. D) RNA polymerase binds to the promotor. E) Lactose binds to the promotor.
D) RNA polymerase binds to the promotor.
4)Which of the following was essential to the success of the Hershey and Chase experiment? A) Understanding that both DNA and protein are carbon-based macromolecules. B) Understanding that both DNA and protein are comprised of many monomers linked together. C) Understanding that viruses are composed of only DNA and protein. D) Understanding that sulfur is present in proteins and that phosphorus is present in DNA. E) Understanding that nitrogen is present in both proteins and DNA.
D) Understanding that sulfur is present in proteins and that phosphorus is present in DNA.
50)Gene mutations are A) always deleterious. B) always beneficial. C) radiation-induced changes only. D) alterations in the normal sequence of bases within a gene. E) alterations to cell cycle.
D) alterations in the normal sequence of bases within a gene.
76)Which of the following is an inacurrate statement regarding ribosomes? A) Ribosomes are produced in the nucleolus of a eukaryotic cell. B) Ribosomes are made of RNA and proteins. C) Ribsomes are composed of two subunits that join together just as protein synthesis begins. D) Each ribsome has a binding site for mRNA, as well as binding sites for three tRNA molecules. E) Ribosomes are the site of both transcription and translation during gene expression.
E) Ribosomes are the site of both transcription and translation during gene expression.
