Chapter 17: From Gene to Protein
 
Chapter Quiz
 

Chapter Quiz


1 .       Who formulated the one gene–one enzyme hypothesis? (Concept 17.1E-Book) [Hint]

 Watson and Crick
 Beadle and Tatum
 Hershey and Chase
 Franklin
 none of the above


2 .       Genetic information of eukaryotic cells is transferred from the nucleus to the cytoplasm in the form of _____. (Concept 17.1E-Book) [Hint]

 proteins
 lipids
 RNA
 carbohydrates
 DNA


3 .       Which one of the following statements is true? (Concept 17.1E-Book) [Hint]

 Each DNA base codes for three amino acids.
 Each gene codes for three proteins.
 It takes three genes to code for one protein.
 Each triplet has many different meanings.
 Each amino acid in a protein is coded for by three bases in the DNA.


4 .       When RNA is being made, the RNA base _____ always pairs with the base _____ in DNA. (Concept 17.1E-Book) [Hint]

 U ... T
 T ... G
 U ... A
 A ... U
 T ... A


5 .       Which one of the following is not associated with RNA? (Concept 17.1E-Book) [Hint]

 ribose
 thymine
 uracil
 phosphates
 single-strandedness


6 .       What mRNA codon would be made from the DNA triplet CGT? (Concept 17.1E-Book) [Hint]

 ATU
 GCA
 TCU
 CTA
 UCG


7 .       The number of nucleotide bases "read" together on the mRNA to designate each amino acid is _____; this unit is called a(n) _____. (Concept 17.1E-Book) [Hint]

 2 ... dipeptide
 3 ... triose
 2 ... anticodon
 3 ... codon
 1 ... amino acid


8 .       The codons AAA, CCC, GGG, and UUU specify the amino acids lysine, proline, glycine, and phenylalanine, respectively. Which of the following DNA sequences would specify the peptide pro-gly-lys-phe if present in the template strand? (Concept 17.1E-Book) [Hint]

 3'-CCCGGGAAATTT-5'
 3'-CCCGGGAAAUUU-5'
 3'-GGGCCCTTTAAA-5'
 5'-GGGCCCUUUAAA-3'
 5'-GGGCCCTTTAAA-3'


9 .       The codons AAA, CCC, GGG, and UUU specify the amino acids lysine, proline, glycine, and phenylalanine, respectively. What peptide sequence would be encoded by the sequence 5'-CCCAAATTTGGG-3', if present in the coding strand of the DNA? (Concept 17.1E-Book) [Hint]

 lys-pro-gly-phe
 pro-lys-phe-gly
 gly-phe-lys-pro
 phe-gly-pro-lys
 gly-phe-pro-lys


10 .       How many nucleotides are needed to code for a protein with 450 amino acids? (Concept 17.1E-Book) [Hint]

 at least 150
 at least 300
 at least 450
 at least 900
 at least 1,350


11 .       In many cases, more than one codon codes for the same amino acid. Because of this, we say that the code is _____. (Concept 17.1E-Book) [Hint]

 inaccurate
 incomplete
 not specific
 redundant
 tricky


12 .       At one point as a cell carried out its day-to-day activities, the nucleotides GAT were paired with the nucleotides CUA. This pairing occurred _____. (Concept 17.2E-Book) [Hint]

 in a double-stranded DNA molecule
 during translation
 during transcription
 when an mRNA codon paired with a tRNA anticodon
 It is impossible to say, given this information.


13 .       Which one of the following catalyzes the linkage between ribonucleotides to form RNA during gene expression? (Concept 17.2E-Book) [Hint]

 RNA polymerase
 RNA ligase
 a ribozyme
 reverse transcriptase
 tRNA


14 .       In eukaryotic cells, a terminator in mRNA synthesis is _____. (Concept 17.2E-Book) [Hint]

 an enzyme whose specific function is to stop synthesis
 a molecule of tRNA that recognizes a stop codon
 a specific nucleotide sequence in DNA that signals the RNA polymerase to stop
 a specific nucleotide sequence in mRNA that signals the RNA polymerase to stop
 none of the above


15 .       In a eukaryotic cell, transcription takes place _____. (Concept 17.2E-Book) [Hint]

 on the cell membrane
 in the rough endoplasmic reticulum
 in the cytoplasm
 on free ribosomes
 in the nucleus


16 .       One strand of a DNA molecule has the following sequence: 3'-AGTACAAACTATCCACCGTC-5'. In order for transcription to occur in that strand, there would have to be a specific recognition sequence, called a(n) _____, to the left of the DNA sequence indicated. (Concept 17.2E-Book) [Hint]

 centromere
 intron
 exon
 AUG codon
 promoter


17 .       During the transcription of a given portion of a DNA molecule _____. (Concept 17.2E-Book) [Hint]

 mRNA is synthesized on both chains of the DNA molecule at once
 mRNA is synthesized on both chains of the DNA molecule, but first on one side and then the other
 mRNA is synthesized on only one of the chains
 half of the mRNA is synthesized on half of one chain; then the other half of the mRNA is made on the other half of the DNA
 any of the above patterns may be found


18 .       In transcription, _____. (Concept 17.2E-Book) [Hint]

 the promoter region acts as an initial binding site for RNA polymerase
 only one of the DNA strands is used as the template
 the RNA nucleotides used are produced by the cell
 all of the above
 none of the above


19 .       In eukaryotes, which of the following mechanisms of gene regulation operates after transcription, but before translation of mRNA into protein? (Concept 17.3E-Book) [Hint]

 RNA splicing and editing
 DNA packing
 action of repressors and activators
 protein degradation
 all of the above


20 .       Usually, in eukaryotic genes _____. (Concept 17.3E-Book) [Hint]

 exons are not transcribed
 introns are not transcribed
 exons are transcribed, but the RNA transcribed from introns does not leave the nucleus
 both introns and exons are transcribed, but the RNA transcribed from them does not leave the nucleus
 exons and introns are transcribed, and the RNA transcribed from them leaves the nucleus


21 .       Which one of the following statements correctly describes mRNA processing? (Concept 17.3E-Book) [Hint]

 Introns are cut out of the primary transcript, and the resulting exons are spliced together.
 Exons are cut out of the primary transcript, and the introns are spliced together.
 Introns are cut out of the primary transcript and spliced together at the end of the transcript.
 Exons are cut out of the primary transcript and transported to the endoplasmic reticulum.
 Introns are cut out of the primary transcript and transported to the ribosomes.


22 .       The structures called snRNPs are _____. (Concept 17.3E-Book) [Hint]

 part of a spliceosome
 involved in the removal of exons from DNA
 a type of specialized carbohydrate
 a critical component of the initiation complex
 all of the above


23 .       Nuclei of eukaryotic cells contain spliceosomes that are made up of _____. (Concept 17.3E-Book) [Hint]

 snRNA
 snRNA and tRNA
 snRNA and DNA
 snRNA and protein
 DNA and protein


24 .       A cell biologist found that two different proteins with largely different structures were translated from two different mRNAs. These mRNAs, however, were transcribed from the same template within the cell nucleus. Which mechanism below could best account for this? (Concept 17.3E-Book) [Hint]

 Different systems of DNA unpacking could result in two different mRNAs.
 A mutation might have altered the gene.
 Exons from the same gene could be spliced in different ways to make different mRNAs.
 Different transcription factors were involved in the transcription of the two mRNAs.
 The two proteins have different functions in the cell.


25 .       The function of tRNA during protein synthesis is to _____. (Concept 17.4E-Book) [Hint]

 deliver amino acids to their proper site during protein synthesis
 guide ribosome subunits out of the nucleus through nuclear pores
 attach mRNA to the small subunit of the ribosome
 process mRNA
 transcribe mRNA


26 .       Which of the following summaries of protein synthesis is correct? (Concept 17.4E-Book) [Hint]

 DNA transposons leave the nucleus, are transported to a ribosome, and catalyze the polymerization of amino acids in a protein.
 DNA exchanges its thymine units with uracil in polymerase. This activates polymerase, and it starts joining amino acids together.
 Transfer RNAs line up on a ribosome, and amino acids bind to them with hydrogen bonds.
 Messenger RNA is made on a DNA template, and then amino-acid-bearing transfer RNAs bind to it through codon-anticodon pairing.
 None of the above.


27 .       The bonds that hold tRNA molecules in the correct three-dimensional shape are _____. (Concept 17.4E-Book) [Hint]

 peptide linkages
 hydrophobic interactions
 covalent bonds
 ionic bonds
 hydrogen bonds


28 .       The translation process in eukaryotes requires all of the following, except _____. (Concept 17.4E-Book) [Hint]

 ribosomes
 RNA polymerase
 aminoacyl-tRNA synthetase enzymes
 transfer RNA
 AUG codons


29 .       During translation in a eukaryotic cell _____. (Concept 17.4E-Book) [Hint]

 ribosomes move into the nucleus
 tRNA carries amino acid molecules to the nucleus, where they are added to a growing polypeptide chain
 polypeptides are synthesized at ribosomes, according to instructions carried by mRNA
 mRNA is synthesized by the bonding of free nucleotides to the bases on the template strand of DNA
 ribosomes move out of the nucleus


30 .       The P site of a ribosome does which one of the following? (Concept 17.4E-Book) [Hint]

 It holds the tRNA that is carrying the next amino acid to be added to the growing polypeptide chain.
 It holds the growing polypeptide chain.
 It helps "unzip" DNA during transcription.
 It catalyzes the addition of amino acids to the tRNAs.
 It recognizes the promoter during transcription initiation.


31 .       The first amino acid inserted into a new polypeptide chain in eukaryotic cells is always _____. (Concept 17.4E-Book) [Hint]

 glycine
 serine
 methionine
 adenosine monophosphate
 alanine


32 .       A sequence of pictures of polypeptide synthesis shows a ribosome holding two transfer RNAs. One tRNA has a polypeptide chain attached to it; the other tRNA has a single amino acid attached to it. What does the next picture show? (Concept 17.4E-Book) [Hint]

 The polypeptide chain is transferred to the single amino acid.
 The tRNA with the single amino acid leaves the ribosome.
 The amino acid is transferred to the polypeptide chain.
 The tRNA with the polypeptide chain leaves the ribosome.
 A third tRNA with an amino acid joins the pair on the ribosome.


33 .       During translation, amino acid chain elongation occurs until _____. (Concept 17.4E-Book) [Hint]

 no further amino acids are needed by the cell
 all tRNAs are empty
 the polypeptide is long enough
 the ribosome encounters a "stop" codon
 the ribosome runs off the end of the mRNA strand


34 .       Polysomes may be defined as _____. (Concept 17.4E-Book) [Hint]

 microfilaments and microtubules
 groups of lysosomes
 groups of ribosomes
 groups of chromosomes
 groups of peroxisomes


35 .       Cells are able to distinguish proteins destined for secretion or for segregation to specific intracellular compartments from those that will remain in the cytoplasm because _____. (Concept 17.4E-Book) [Hint]

 there are two types of ribosomes: one group that synthesizes cytoplasmic proteins only, and another type that synthesizes secreted or compartment-specific proteins only
 some proteins, as they begin to be synthesized, contain a signal region that causes the ribosome with its growing polypeptide to attach to the ER and translocate the polypeptide into the lumen (space) of the ER
 proteins destined for secretion or for a specific compartment are all synthesized in the nucleus, whereas cytoplasmic proteins are all synthesized in the cytoplasm
 each compartment in the cell (the nucleus, lysosome, and so forth) has its own set of ribosomes that synthesize proteins unique to that compartment
 ribosomes contain two types of subunits


36 .       What is the proper order of the following events in the expression of a eukaryotic gene?

1. translation

2. RNA processing

3. transcription

4. modification of protein

(Concept 17.4E-Book) [Hint]

 1, 2, 3, 4
 3, 2, 1, 4
 4, 2, 3,1
 2 ,3, 4, 1
 1, 2, 4, 3


37 .       What is a key difference in gene expression between eukaryotic and prokaryotic cells? (Concept 17.6E-Book) [Hint]

 In prokaryotes, proteins are assembled directly from DNA.
 RNA polymerases are involved only in initiation in eukaryotes.
 In prokaryotic cells, the mRNA transcript is immediately available as mRNA without processing.
 In eukaryotic cells, transcribed RNA sequences function as termination signals.
 Prokaryotes do not contain ribosomes.


38 .       A geneticist found that a particular mutation had no effect on the polypeptide encoded by the gene. This mutation probably involved _____. (Concept 17.7E-Book) [Hint]

 deletion of one nucleotide
 a missense mutation
 insertion of one nucleotide
 a nonsense mutation
 a silent mutation


39 .       Which one of the following types of mutation is least likely to affect the function of the protein corresponding to the gene in which the mutation occurs? (Concept 17.7E-Book) [Hint]

 addition of single bases
 base-pair substitution
 transposition
 deletion of single bases
 nonsense mutation


40 .       A base-pair substitution mutation in a germ cell line is likely to have no effect on phenotype if the substitution _____. (Concept 17.7E-Book) [Hint]

 forms a new stop codon
 occurs in an intron
 changes a stop codon to a codon specifying an amino acid
 changes the structure of an enzyme
 prevents the initiation of transcription of the DNA sequence that codes for ATP synthase


41 .       A virus infects a cell and randomly inserts many short segments of DNA containing a stop codon throughout the organism's chromosomes. This will probably cause _____. (Concept 17.7E-Book) [Hint]

 manufactured proteins to be short and defective
 the DNA to break up into thousands of short segments
 incorrect pairing between mRNA codons and amino acids
 no bad effects, as long as the stop codons are not also inserted into tRNA
 all of the above


42 .       A point mutation in which a single base pair is inserted or deleted from DNA is called a(n) _____. (Concept 17.7E-Book) [Hint]

 nonsense mutation
 frame-shift mutation
 inversion mutation
 translocation mutation
 missense mutation


43 .       Ultraviolet (UV) radiation is damaging to cells because it _____. (Concept 17.7E-Book) [Hint]

 pokes holes in the nuclear envelope
 blocks all translation
 causes mutations in the DNA
 deactivates the enzymes needed for DNA replication
 shreds the cytoskeleton







©2005 Pearson Education, Inc., publishing as Benjamin Cummings