General ---------Biology----------------------------------------------------- ------------------Online---------------------------------------bwilcox@edison.edu Ch. 17 From Gene to Protein

Ch. 17 From Gene to Protein

  1. What is the relationship among DNA, a gene, and a chromosome?
     a. A chromosome contains hundreds of genes which are composed of
        protein.
     b. A chromosome contains hundreds of genes which are composed of
        DNA.
     c. A gene contains hundreds of chromosomes which are composed of
        protein.
     d. A gene is composed of DNA, but there is no relationship to a
        chromosome.
     e. A gene contains hundreds of chromosomes which are composed of
        DNA.
Check your answer by viewing Fig. 17.3.
 

  2. What is one function of a signal sequence?
     a. to direct an mRNA molecule into the cisternal space of ER
     b. to bind RNA polymerase to DNA and initiate transcription
     c. to terminate translation of the messenger RNA
     d. to attach ribosomes synthesizing secretory proteins to the ER
     e. to signal the initiation of transcription
 

  4. The dictionary of the genetic code is the same for all organisms, from bacteria to mammals. From this, one can logically assume all of the following EXCEPT:
     a. A gene from an organism could theoretically be expressed by any
        other organism.
     b. All organisms have a common ancestor.
     c. DNA was the first genetic material.
     d. Related organisms have many similar genes.

  5. Where is the attachment site for RNA polymerase?
     a. structural gene region
     b. initiation region
     c. promoter region
     d. operator region
     e. regulator region

  6. What is an anticodon part of?
     a. DNA
     b. tRNA
     c. mRNA
     d. ribosome
     e. activating enzyme

  12. A particular eukaryotic protein is 300 amino acids long. Which of
     the following could be the number of nucleotide pairs in the DNA that
     codes for this protein?
     a. 3
     b. 100
     c. 300
     d. 900
     e. 1800

 13. A particular triplet of bases in the coding sequence of DNA is AGT.
     What is the corresponding triplet in the complementary strand of
     DNA?
     a. AGT
     b. UCA
     c. TCA
     d. GAC
     e. TCA in eukaryotes, but UCA in prokaryotes

 14. A particular triplet of bases in the coding sequence of DNA is AGT.
     The corresponding codon for the mRNA transcribed from the gene is
     a. AGT.
     b. UCA.
     c. TCA.
     d. AGU.
     e. Either UCA or TCA, depending on wobble in the first base.

 15. A particular triplet of bases in the coding sequence of DNA is AGT.
     The anticodon on the tRNA that binds the mRNA codon transcribed from
     the gene is
     a. AGT.
     b. UCA.
     c. TCA.
     d. AGU.
     e. Either UCA or TCA, depending on wobble in the first base.

 17. What are the coding segments of a stretch of eukaryotic DNA called?
     a. introns
     b. exons
     c. codons
     d. replicons
     e. transposons

 18. All of the following are directly involved in translation EXCEPT
     a. mRNA.
     b. tRNA.
     c. ribosomes.
     d. DNA.
     e. amino acid-activating enzymes.

20. RNA differs from DNA in that RNA
          1. contains ribose as its sugar.
          2. is found only in cytoplasm.
          3. contains uracil instead of thymine.
     a. 1
     b. 2
     c. 3
     d. 1 and 3 are correct.
     e. 1, 2, and 3 are correct.

 26. A frameshift mutation could result from
     a. a base insertion only.
     b. a base deletion only.
     c. a base substitution only.
     d. deletion of three consecutive bases.
     e. either an insertion or a deletion of a base.

 27. If the triplet UUU codes for the amino acid phenylalanine in
     bacteria, then in plants UUU should code for
     a. leucine.
     b. valine.
     c. cystine.
     d. phenylalanine.
     e. proline.

 28. Which point mutation would be most likely to have a catastrophic
     effect on the functioning of a protein?
     a. a base substitution
     b. a base deletion near the start of the coding sequence
     c. a base deletion near the end of the coding sequence, but not in
        the terminator codon
     d. deletion of three bases near the start of the coding sequence,
        but not in the initiator codon
     e. a base insertion near the end of the coding sequence, but not in
        the terminator codon

 29. Choose the answer that has these events of protein synthesis in the
     proper sequence.
          1. An aminoacyl-tRNA binds to the A site.
          2. A peptide bond forms.
          3. tRNA leaves the P site and the P site remains vacant.
          4. A small ribosomal subunit associates with mRNA.
          5. tRNA translocates to the P site.

     a. 1, 3, 2, 4, 5
     b. 4, 1, 2, 5, 3
     c. 5, 4, 3, 2, 1
     d. 4, 1, 3, 2, 5
     e. 2, 4, 5, 1, 3
Check your answer by viewing Fig. 17.23 A summary of trans...
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 Refer to Figure 17.4 "The dictionary of the genetic code" in your text to answer the following question(s).

33. A possible sequence of nucleotides in DNA that would code for the
     polypeptide sequence Phe-Leu-Ile-Val would be
     a. 5' TTG-CTA-CAG-TAG 3'
     b. 3' AAC-GAC-GUC-AUA 5'
     c. 5' AUG-CTG-CAG-TAT 3'
     d. 3' AAA-AAT-ATA-ACA 5'
     e. 3' AAA-GAA-TAA-CAA 5'

 34. What amino acid sequence will be generated, based on the following
     mRNA codon sequence?   5' AUG-UCU-UCG-UUA-UCC-UUG
     a. met-arg-glu-arg-glu-agr
     b. met-glu-arg-arg-gln-leu
     c. met-ser-leu-ser-leu-ser
     d. met-ser-ser-leu-ser-leu
     e. met-leu-phe-arg-glu-glu

 35. A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. What
     is the sequence in DNA that codes for this peptide?
     a. 3' UUU-CCC-AAA-GGG-UUU-CCC
     b. 3' AUG-AAA-GGG-TTT-CCC-AAA-GGG
     c. 3' AAA-GGG-TTT-CCC-AAA-GGG
     d. 5' GGG-AAA-TTT-AAA-CCC-ACT-GGG
     e. 5' ACT-TAC-CAT-AAA-CAT-TAC-UGA

 36. What is the sequence of a peptide based on the mRNA sequence
     5'UUUUCUUAUUGUCUU?
     a. leu-cys-tyr-ser-phe
     b. cyc-phe-tyr-cys-leu
     c. phe-leu-ile-met-val
     d. leu-pro-asp-lys-gly
     e. phe-ser-tyr-cys-leu

 37. Suppose the following DNA sequence was mutated from
     AGAGAGAGAGAGAGAGAGA to AGAAGAGAGATCGAGAGA. What amino acid sequence
     will be generated based on this mutated DNA?
     a. arg-glu-arg-glu-agr-glu
     b. glu-arg-glu-leu-leu-leu
     c. ser-leu-ser-leu-ser-leu
     d. ser-ser-leu
     e. leu-phe-arg-glu-glu-glu

39. All of the following are found in prokaryotic messenger RNA EXCEPT
     a. the AUG codon.
     b. the UGA codon.
     c. introns.
     d. uracil.
     e. cytosine.

 41. During translation, chain elongation continues until what happens?
     a. No further amino acids are needed by the cell.
     b. All tRNAs are empty.
     c. The polypeptide is long enough.
     d. Chain terminator codons occur.
     e. The ribosomes run off the end of mRNA.

42. Which of the following represents a similarity between RNA and DNA?
     a. the presence of a double-stranded helix
     b. the presence of uracil
     c. the presence of an OH group on the 2' carbon of the sugar
     d. nucleotides consisting of a phosphate, sugar, and nitrogen base
     e. repair systems that correct genetic code errors

43. What are ribosomes composed of?
     a. two subunits, each consisting of rRNA only
     b. two subunits, each consisting of several proteins only
     c. both rRNA and protein
     d. mRNA, rRNA, and protein
     e. mRNA, tRNA, rRNA, and protein

 46. Sickle-cell anemia is probably the result of which kind of
     mutation?
               1. point only
               2. frameshift only
               3. nonsense only
               4. nondisjunction only
     a. 1
     b. 2
     c. 3
     d. 4
     e. both 2 and 4

For an illustration of framshift mutations, click here.

52. According to the signal hypothesis, ribosomes are directed to the ER
     membrane
     a. by a specific characteristic of the ribosome itself, which
        distinguishes free ribosomes from bound ribosomes.
     b. by a certain amino acid sequence at the beginning of the
        polypeptide chain being synthesized by the ribosome.
     c. by moving through a channel from the nucleus.
     d. by a chemical signal given off the ER.
     e. by a signal sequence of RNA that precedes the start codon of the
        message.

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 60. We recently read about an outbreak of Ebola virus in Zaire.
     Originally, it was thought that the outbreak was caused by a new
     virus that resulted from a mutation in the original virus. Closer
     examination showed that the viruses were the same. How would you
     tell if a virus had mutated?
     a. All of these are correct.
     b. Look for differences in its physical characteristics (with an
        electron microscope).
     c. Look for differences in the amino acid sequence of the proteins
        the virus produces.
     d. Look for differences in the nucleotide sequence of its DNA (or
        RNA).
     e. Look for differences in its pattern of infection.

 61. Your friend Forrest wants to create a new "green" shrimp. He plans
     on growing normal shrimp in green light because, he says, the green
     light will cause mutations that make the shrimp green. You must tell
     him this is not a good idea because
     a. if the green light is capable of causing such mutations, it will
        also turn him green.
     b. mutations are random, and no agent (even green light) can cause a
        specific mutation like turning shrimp green.
     c. it cannot work because everyone knows that water absorbs green
        light (that's why lakes and ponds are green).
     d. the green shrimp would be mutagenic and anyone eating them would
        be in danger of turning green.
     e. the color of a shrimp has nothing to do with its genes.