Biology 2010 Test 4 Genes-Proteins  Name:__________________________________

Version 1

 

Ch. 17 From Gene to Protein

 

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

1A) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

1B) enzymes are made of DNA, and affected individuals lack DNA polymerase.

1C) many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA.

1D) certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors.

1E) metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies.

 

2        We now know that the one gene-one enzyme hypothesis is not entirely accurate because

2A) many genes code for proteins that are not enzymes.

2B) a single gene codes for a single polypeptide chain, and many enzymes are made up of more than one polypeptide chain.

2C) many genes code for RNA molecules that have no enzymatic activity.

2D) A and B only

2E) A, B, and C

 

3         Which of the following represents a similarity between RNA and DNA?

3A) Both are double-stranded.

3B) the presence of uracil

3C) the presence of an OH group on the 2' carbon of the sugar

3D) nucleotides consisting of a phosphate, sugar, and nitrogenous base

3E) Both are found exclusively in the nucleus.

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

4A) proteins, triglycerides, and testosterone

4B) proteins, ATP, and DNA

4C) ATP, RNA, and DNA

4D) alpha glucose, ATP, and DNA

4E) proteins, carbohydrates, and ATP

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

5A) AGT.

5B) UGA.

5C) TCA.

5D) ACU.

5E) either UCA or TCA, depending on wobble in the first base

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6        A particular eukaryotic protein is 300 amino acids long. Which of the following could be the maximum number of nucleotides in the DNA that codes for the amino acids in this protein?

6A) 3

6B) 100

6C) 300

6D) 900

6E) 1,800

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7        If the triplet CCC codes for the amino acid proline in bacteria, then in plants CCC should code for

7A) leucine.

7B) valine.

7C) cystine.

7D) phenylalanine.

7E) proline.

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8        Which of the following are transcribed from DNA?

8A) protein

8B) exons

8C) rRNA

8D) B and C only

8E) A, B, and C

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

9A) RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase.

9B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to fall off the DNA and release the transcript.

9C) RNA polymerase transcribes through an intron, and the snRNPs cause the polymerase to let go of the transcript.

9D) Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome.

9E) RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA.

 

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

10A) many noncoding nucleotides are present in mRNA.

10B) there is redundancy and ambiguity in the genetic code.

10C) many nucleotides are needed to code for each amino acid.

10D) nucleotides break off and are lost during the transcription process.

10E) there are termination exons near the beginning of mRNA.

 

11    Introns are significant to biological evolution because

11A) their presence allows exons to be moved around more easily, creating proteins with new combinations of functional domains.

11B) they protect the mRNA from degeneration.

11C) they are translated into essential amino acids.

11D) they maintain the genetic code by preventing incorrect DNA base pairings.

11E) they correct enzymatic alterations of DNA bases.

 

12    All of the following are directly involved in translation except

12A) mRNA.

12B) tRNA.

12C) ribosomes.

12D) DNA.

12E) aminoacyl-tRNA synthetase enzymes.

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13    Accuracy in the translation of mRNA into the primary structure of a protein depends on specificity in the

13A) binding of ribosomes to mRNA.

13B) shape of the A and P sites of ribosomes.

13C) bonding of the anticodon to the codon.

13D) attachment of amino acids to tRNAs.

13E) both C and D

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

14A) none of the proteins in the cell will contain phenylalanine.

14B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.  

14C) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons.

14D) the ribosome will skip a codon every time a UUU is encountered.

14E) None of the above will occur; the cell will recognize the error and destroy the tRNA.

 

15    From the following list, which is the first event in translation in eukaryotes?

15A) elongation of the polypeptide

15B) base pairing of activated methionine-tRNA to AUG of the messenger RNA

15C) binding of the larger ribosomal subunit to smaller ribosomal subunits

15D) covalent bonding between the first two amino acids

15E) Both B and D occur simultaneously.

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16    During translation, chain elongation continues until what happens?

16A) No further amino acids are needed by the cell.

16B) All tRNAs are empty.

16C) The polypeptide is long enough.

16D) A stop codon is encountered.

16E) The ribosomes run off the end of mRNA.

 

17    Sickle-cell disease is probably the result of which kind of mutation?

17A) point  

17B) frameshift  

17C) nonsense

17D) nondisjunction

17E) both B and D

 

18    A frameshift mutation could result from

18A) a base insertion only.

18B) a base deletion only.

18C) a base substitution only.

18D) deletion of three consecutive bases.

18E) either an insertion or a deletion of a base.

 

 

 

 

 

 

 

 

 

Each of the following is a modification of the sentence THECATATETHERAT.

                A.    THERATATETHECAT

                B.    THETACATETHERAT

                C.    THECATARETHERAT

                D.    THECATATTHERAT

                E.    CATATETHERAT

 

19     Which of the above is analogous to a frameshift mutation?

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20     When does translation begin in prokaryotic cells?

20A) after a transcription initiation complex has been formed

20B) during transcription

20C) after the 5' caps are converted to mRNA

20D) once the pre-mRNA has been converted to mRNA

20E) as soon as the DNA introns are removed from the template

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Ch. 19. The organization and Contol of Eukaryotic Genomes

 

21    In a nucleosome, what is the DNA wrapped around?

21A) polymerase molecules

21B) ribosomes

21C) mRNA

21D) histones

21E) nucleolus protein

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22     Under the electron microscope, unfolded chromatin resembles "beads on a string." What do the "beads" represent?

22A) nucleosomes

22B) ribosomes

22C) beadosomes

22D) molecules of DNA polymerase

22E) molecules of RNA polymerase

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23     If a cell were unable to produce histone proteins, which of the following would be expected to occur?

23A) There would be an increase in the amount of "satellite" DNA produced during centrifugation.

23B) The cell's DNA couldn't be packed into its nucleus.

23C) Spindle fibers would not form during prophase.

23D) Amplification of other genes would compensate for the lack of histones.

23E) Pseudogenes would be transcribed to compensate for the decreased protein in the cell.

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24    Why do histones bind tightly to DNA?

24A) Histones are positively charged, and DNA is negatively charged.

24B) Histones are negatively charged, and DNA is positively charged.

24C) Both histones and DNA are strongly hydrophobic.

24D) Histones are covalently linked to the DNA.

24E) Histones are highly hydrophobic, and DNA is hydrophilic.

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25    Muscle cells and nerve cells in one species of animal owe their differences in structure to

25A) having different genes.

25B) having different chromosomes.

25C) using different genetic codes.

25D) differential gene expression.

25E) having unique ribosomes.

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26    In which of the following would you expect to find the most methylation of DNA?

26A) tandem arrays for ribosomal genes

26B) pseudogenes

26C) inactivated mammalian X chromosomes

26D) globin genes

26E) transposons

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27     Approximately what proportion of the DNA in the human genome codes for proteins or functional RNA?

27A) 83%

27B) 46%

27C) 32%

27D) 13%

27E) 2%

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28     Two potential devices that eukaryotic cells use to regulate transcription are DNA ________ and histone ________.

28A) methylation; amplification

28B) amplification; methylation

28C) acetylation; methylation

28D) methylation; acetylation

28E) amplification; acetylation

 

29     In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of

29A) transcription.

29B) translation.

29C) mRNA stability.

29D) mRNA splicing.

29E) protein stability.

 

30    The incidence of cancer increases dramatically with age because

30A) the Ras protein is more likely to be hyperactive after age sixty.

30B) proteasomes become more active with age.

30C) as we age, normal cell division inhibitors cease to function.

30D) the longer we live, the more mutations accumulate.

30E) tumor-suppressor genes are no longer able to repair damaged DNA.

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31     Steroid hormones produce their effects in cells by

31A) activating key enzymes in metabolic pathways.

31B) activating translation of certain mRNAs.

31C) promoting the degradation of specific mRNAs.

31D) binding to intracellular receptors and promoting transcription of specific genes.

31E) promoting the formation of looped domains in certain regions of DNA.

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32    Which of the following can contribute to the development of cancer?

32A) random spontaneous mutations

32B) mutations caused by X-rays

32C) transposition

32D) A and B only

32E) A, B, and C

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Chapter 20. DNA Technology and Genomics

 

33    Plasmids are important in biotechnology because they are

33A) a vehicle for the insertion of foreign genes into bacteria.

33B) recognition sites on recombinant DNA strands.

33C) surfaces for protein synthesis in eukaryotic recombinants.

33D) surfaces for respiratory processes in bacteria.

33E) proviruses incorporated into the host DNA.

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34     If you discovered a bacterial cell that contained no restriction enzymes, which of the following would you expect to happen?

34A) The cell would be unable to replicate its DNA.

34B) The cell would create incomplete plasmids.

34C) The cell would be easily infected and lysed by bacteriophages.

34D) The cell would become an obligate parasite.

34E) Both A and D would occur.

 

35     What is the enzymatic function of restriction enzymes?

35A) to add new nucleotides to the growing strand of DNA

35B) to join nucleotides during replication

35C) to join nucleotides during transcription

35D) to cleave nucleic acids at specific sites

35E) to repair breaks in sugar-phosphate backbones

 

36      What is a cloning vector?

36A) an enzyme that cuts DNA into restriction fragments

36B) a DNA probe used to locate a particular gene in the genome

36C) an agent, such as a plasmid, used to transfer DNA from an in vitro solution into a living cell

36D) the laboratory apparatus used to clone genes

36E) the sticky end of a DNA fragment

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37     Bacteria containing recombinant plasmids are often identified by which process?

37A) examining the cells with an electron microscope

37B) using radioactive tracers to locate the plasmids

37C) exposing the bacteria to an antibiotic that kills cells lacking the plasmid

37D) removing the DNA of all cells in a culture to see which cells have plasmids

37E) producing antibodies specific for each bacterium containing a recombinant plasmid

 

38    The polymerase chain reaction is important because it allows us to

38A) insert eukaryotic genes into prokaryotic plasmids.

38B) incorporate genes into viruses.

38C) make DNA from RNA transcripts.

38D) make many copies of a targeted segment of DNA.

38E) insert regulatory sequences into eukaryotic genes.

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39    Restriction fragments of DNA are typically separated from one another by which process?

39A) filtering

39B) centrifugation

39C) gel electrophoresis

39D) PCR

39E) electron microscopy

 

40     Genetically engineered plants

40A) are more difficult to engineer than animals.

40B) include a transgenic rice plant that could help prevent vitamin A deficiency.

40C) are being rapidly developed, but traditional plant breeding programs are still the only method used to develop new plants.

40D) are able to fix nitrogen themselves.

40E) are banned throughout the world.

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Extra Credit. 5pts each question.

 

1. How are RFLPs used in generating unique DNA fingerprints?

 

RFLP are fragments of DNA that are produced by restriction enzymes that cleave DNA at tandem repeat locations. Since the number of tandem repeats is highly variable among individuals (this is a neutral mutation and can accumulate), this produces many different fragments. Gel electrophoresis is used to separate the fragments into bands and each individual should have a different banding pattern.

 

 

 

 

2. A paleontologist has recovered a bit of tissue from the 400-year-old preserved skin of an extinct dodo (a bird). The researcher would like to compare DNA from the sample with DNA from living birds. What molecular technique would be  most useful for increasing the amount of dodo DNA available for testing?

 

The procedure needed to increase the amount of DNA is called PCR (polymerase chain reaction). In this procedure, small amounts of DNA are doubled each cycle, as primers add free nucleotides to existing DNA, causing the amounts of DNA to increase geometrically.