Chapter Quiz

The P site of a ribosome does which one of the following? (p. 316)

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 polypeptide chain of adjacent amino acids.
It recognizes the promoter during transcription initiation.


Who of the following formulated the one gene–one enzyme hypothesis? (p. 304)

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


Mutations are _________. (p. 322)

changes in the composition of a DNA molecule
changes in genes that ultimately cause genetic diversity
the source of new alleles
chemical changes in the genetic material
all of the above


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? (p. 322)

addition of single bases
base substitution
deletion of single bases
misalignment deletion


How many nucleotides are needed to code for a protein with 450 amino acids? (p. 306)

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


There are six different codons signaling for the placement of the amino acid leucine in a protein. Because of this, we say that the code is _____. (p. 308)



When RNA is being made, the RNA base ____ always pairs with the base _____ in DNA. (p. 307)

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


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 _____. (p. 309)

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


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
(p. 304)



In a eukaryotic cell, transcription takes place _____. (p. 306)

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


Which one of the following is NOT associated with RNA? (p. 306)



A terminator in mRNA synthesis is _____. (p. 309)

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 a stop
Arnold Schwarzenegger
none of the above


The DNA code is CGT. What messenger RNA is made from this? (p. 307)



Which one of the following catalyzes the linkage between ribonucleotides to form RNA? (p. 309)

RNA polymerase
RNA ligase
a ribozyme
reverse transcriptase


In transcription, _____. (p. 309)

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


The translation process in eukaryotes requires all of the following, EXCEPT _____. (p. 309)

RNA polymerase
aminoacyl tRNA synthetase enzymes
transfer RNA
AUG codons


A point mutation in which a single base pair is inserted or deleted from DNA is called a(n) _____. (p. 323)

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


Which one of the following processes does NOT take place in the nucleus? (p. 313)

replication of DNA
assembly of ribosomes
removal of introns from RNA


During the transcription of a given portion of a DNA molecule _____. (p. 309)

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


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 _____. (p. 309)

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


One strand of a DNA molecule in a prokaryote has the following sequence: 3'-AGTACAAACTATCCACCGTC-5'. If that strand were transcribed, the resulting molecule would have the sequence _____. (p. 309)



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. (p. 309)

AUG codon


In eukaryotes, which of the following mechanisms of gene regulation operates after transcription but before translation of mRNA into protein? (p. 311)

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


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 gene in the cell nucleus. Which mechanism below could best account for this? (p. 313)

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.
The gene could be transcribed in different directions.
The two proteins have different functions in the cell.


The structures called snRNPs are _____. (p. 312)

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


Usually, in eukaryotic genes _____. (p. 312)

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


Nuclei of eukaryotic cells contain spliceosomes that are made up of _____. (p. 312)

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


Which summary of protein synthesis is correct? (p. 309)

DNA transposons leave the nucleus, go 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 line up on it in through codon-anticodon pairing.
None of the above.


Polysomes may be defined as _____. (p. 319)

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


Information is transferred from the nucleus to the cytoplasm of eukaryotic cells in the form of _____. (p. 313)

nucleic acids


The function of tRNA during protein synthesis is to _____. (p. 313)

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


Which one of the following statements correctly describes mRNA processing? (p. 312)

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.


A geneticist found that a particular mutation had no effect on the polypeptide encoded by a gene. This mutation probably involved _____. (p. 322)

deletion of one nucleotide
alteration of the start codon
insertion of one nucleotide
deletion of the entire gene
substitution of one nucleotide


Imagine an error occurring during DNA replication in a cell, so that where there is supposed to be a T in one of the genes, there is instead a G. What effect will this probably have on the cell? (p. 322)

Each of its kinds of proteins will contain an incorrect amino acid.
An amino acid will be missing from each of its kinds of proteins.
One of its kinds of proteins might contain an incorrect amino acid.
An amino acid will be missing from one of its kinds of proteins.
The amino acid sequence of one of its kinds of proteins will be completely changed.


A particular ____ carry the information for making a particular polypeptide, but ____ can be used to make any polypeptide. (p. 304)

gene and ribosome ... tRNA and mRNA
gene and mRNA ... a ribosome and tRNA
ribosome and mRNA ... a gene and tRNA
gene and tRNA ... a ribosome and mRNA
tRNA and ribosome ... a gene and mRNA


The nucleotide sequence of a DNA codon is GTA. A messenger RNA molecule with a complementary codon is transcribed from the DNA. In the process of protein synthesis, a transfer RNA pairs with the mRNA codon. What is the nucleotide sequence of the tRNA anticodon? (p. 307)



A base-substitution mutation in a germ cell line is likely to have NO effect on phenotype if the substitution _____. (p. 322)

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


During the process of translation (polypeptide synthesis), ____ matches an mRNA codon with the proper amino acid. (p. 313)

a ribosome
DNA polymerase
transfer RNA
messenger RNA


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? (p. 318)

The polypeptide chain moves over and bonds to the single amino acid.
The tRNA with the single amino acid leaves the ribosome.
The amino acid moves over and bonds 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.


During translation in a eukaryotic cell _____. (p. 313)

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
French cells are able to speak to German cells


Ultraviolet (UV) radiation is damaging because it ____________. (p. 323)

prevents DNA transcription
prevents DNA translation
causes mutations in the DNA
deactivates the enzymes needed for DNA replication
inhibits protein synthesis


The number of nucleotide bases "read" together on the mRNA to designate each amino acid is __________; this unit is called a __________. (p. 307)

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


Protein synthesis, controlled by DNA, requires all of the following EXCEPT _____. (p. 305)

amino acids
endoplasmic reticulum


The bonds that hold tRNA molecules in the correct three-dimensional shape are _____. (p. 314)

peptide linkages
hydrophobic interactions
covalent bonds
ionic bonds
hydrogen bonds


During translation, amino acid chain elongation occurs until _____. (p. 318)

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


Which one of the following statements is true? (p. 307)

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.


Genetic mutations _____. (p. 323)

occur spontaneously
are most common in body parts that are not used very often
are most common in body parts that are used frequently
are mainly caused by diseases associated with fetal development
are always passed on to the next generation


A codon consists of how many nucleotides? (p. 307)

only one
a doublet
a triplet
a quadruplet
a sextet


Amino acid activation involves _____. (p. 316)

thioester linkages (such as in acetyl CoA)
energizing with GTP as the energy source
attachment to the ribosome
attachment to mRNA
attachment to tRNA


The first amino acid inserted into a new polypeptide chain in eukaryotic cells is always _____. (p. 317)

adenosine monophosphate



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