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10: The Structure and Function of DNA
This activity contains 55 questions.
The elderly can afford vaccines more than other people.
Elderly people can have a compromised immune system because of advanced age and other age-related health issues.
Elderly people travel more than other groups and are therefore more likely to catch an infectious disease such as the flu.
Elderly people exposed to the flu of 1918-1919 have a weakened immune system and thus require flu vaccines.
The vaccine is scientifically designed for older people.
Which one of the following is a list of the four bases contained in DNA?
cytosine, guanine, thymine, uracil
adenine, guanine, cytosine, thymine
guanine, pyroline, thymine, uracil
adenine, guanine, uracil, thymine
adenine, guanine, purine, thymine
Which one of the following lists the chemical components of a nucleotide?
a sugar and a phosphate group only
a sugar and a purine
a nitrogenous base, a sugar, and a phosphate group
a nitrogenous base and a sugar only
a sugar and a pyrimidine
Monomers for the synthesis of DNA are called _____.
Which one of the following is uniquely associated with RNA?
hydrogen bonding between the two nucleotide strands
existence of two different types of RNA with two different functions
existence of a double-stranded molecule
What research technique was most helpful to Watson and Crick in their attempt to determine the structure of DNA?
A major characteristic of the structure of DNA is that __________.
the ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1
the ratio of A to G is close to 1:1 and the ratio of T to C is close to 1:1
A + G = C + G
the ratio of A to C is close to 1:1 and the ratio of G to T is close to 1:1
A + T = G + C
The two sugar-phosphate strands with their associated nitrogenous bases of a DNA molecule are joined to each other by __________.
hydrogen bonds between nucleotide bases
covalent bonds between carbon atoms in deoxyribose molecules
covalent bonds between nitrogen atoms in adenine and in thymine
ionic bonds between guanine and cytosine
Which one of the following statements is true about double-stranded DNA?
The strands are parallel and are synthesized in the same direction.
It contains disulfide bonds.
It is a nonhelical, linear molecule.
Adenine and uracil are present in equal amounts.
The two strands are complementary.
The genetic information in DNA is contained in __________.
the three-dimensional, double-helix structure of the DNA
the sequence of amino acids that make up the DNA molecule
the variation in the structure of nucleotides that make up the DNA molecule
the types of sugars used in making the DNA molecule
the sequence of nucleotides along the length of one strand of the DNA molecule
Which one of the following statements applies to the Watson-Crick model for DNA?
The purine (double ring) bases pair with the purines.
The two strands of the helix are held together by hydrogen bonds.
The two strands of the DNA helix are exact replicas of each other.
The nitrogenous bases are attached to the phosphates of the DNA molecule.
The framework of the helix consists of sugar-nucleotide units.
One strand of a DNA molecule has the base sequence ATAGGT. The complementary base sequence on the other strand of DNA will be _____.
DNA replication __________.
provides proof of the one geneone enzyme hypothesis
provides the template for transcription (synthesis of mRNA)
only occurs when the cell is depleted of nutrients
provides exact copies of chromosomes for the progeny of cell division and assures perpetuation of the species
is spontaneous and not governed by internal factors
During the replication of DNA molecules, __________.
the cell undergoes mitosis
only one strand of the molecule acts as a template
RNA polymerases catalyze the reaction
errors never occur
both strands of the DNA molecule serve as templates
Two new strands of DNA grow as bases are added by the enzyme _____.
bacterial duplicating complex
A gene is usually __________.
the information for making a polypeptide
made by a ribosome
the same thing as a chromosome
made of protein
made of RNA
The number of nucleotide bases on the mRNA that together designate an amino acid is _____; this unit is called a(n) _____.
one ... amino acid
two ... dipeptide
three ... triose
two ... anticodon
three ... codon
Which one of the following statements is true?
It takes three genes to code for one protein.
Each triplet of bases can mean different things.
Each gene codes for three proteins.
Each DNA base codes for three amino acids.
Each amino acid in a protein is coded for by three bases in the DNA.
When messenger RNA (mRNA) is being made, the RNA base _____ always pairs with the base _____ in DNA.
A ... U
U ... T
T ... G
T ... A
U ... A
The DNA code is CGT. What is the sequence of nucleotides in the transcribed mRNA?
During the transcription of a given portion of a DNA molecule __________.
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
mRNA is synthesized from both chains of the DNA molecule, but in different directions
mRNA is synthesized from both chains of the DNA molecule
mRNA is synthesized from only one of the DNA strands, which is selected at random
mRNA is synthesized on only one of the chains
One strand of a DNA molecule has the following sequence: AGTACAAACTATCCACCGTC. For transcription of this sequence to occur, there would have to be a specific recognition sequence for the RNA polymerase, called a(n) _____, to the left of the DNA sequence indicated.
Assume that a cell is carrying out its day-to-day activities. At one point, the nucleotides GAT are paired with the nucleotides CUA. This pairing occurred __________.
It is impossible to say, given this information.
when an mRNA codon paired with a tRNA anticodon
during replication of DNA
A terminator of mRNA synthesis is __________.
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 to transcription
a nucleotide sequence within an intron
Which one of the following catalyzes the linkage between nucleotides to form mRNA?
In transcription, __________.
the DNA promotor region acts as an initial binding site for RNA polymerase
RNA polymerase builds the mRNA from two different directions on the DNA template strand
the DNA terminator region acts as an initial binding site for RNA polymerase
two DNA strands are used as a template for the synthesis of RNA
DNA nucleotides are used
Genetic information is transferred from the nucleus to the cytoplasm of eukaryotic cells in the form of _____.
A cell biologist found that two different proteins with 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?
A mutation might have altered the gene.
Different systems of DNA unpacking could result in two different mRNAs.
Exons from the same gene could be spliced in different ways to make different mRNAs.
The gene could be transcribed in different directions to produce two different proteins.
The two proteins have different functions in the cell.
Usually, in transcription of eukaryotic genes __________.
introns are not transcribed
both introns and exons are transcribed, but the RNA transcribed from them does not leave the nucleus
exons are not transcribed
exons and introns are transcribed, but the RNA transcribed from introns does not leave the nucleus
exons and introns are transcribed, and the RNA transcribed from them leaves the nucleus
Which one of the following statements correctly describes mRNA processing in eukaryotes?
Exons are cut out, and the introns are spliced together.
Exons are cut out and transported to smooth endoplasmic reticulum.
Introns are cut out, and the resulting exons are spliced together.
Introns are cut out and spliced together at the end of the mRNA.
Introns are cut out and transported to the ribosomes.
A mutation in a DNA sequence is likely to have no effect on phenotype if the mutation __________.
substantially changes the structure of an enzyme
occurs in an intron
changes a stop codon to a codon specifying an amino acid
prevents the initiation of transcription of the DNA sequence that codes for ATP synthase
forms a new stop codon
In a eukaryotic cell, transcription takes place __________.
in the rough endoplasmic reticulum
on the cell membrane
in the cytoplasm
in the nucleus
The function of tRNA during protein synthesis is to __________.
guide ribosome subunits out of the nucleus through nuclear pores
deliver amino acids to the growing polypeptide chain
attach mRNA to the small subunit of the ribosome
During the process of translation, _____ matches an mRNA codon with the proper amino acid.
During translation in a eukaryotic cell __________.
polypeptides are synthesized at ribosomes, according to instructions carried by mRNA
tRNA carries amino acid molecules to the nucleus, where they are added to a growing polypeptide chain
mRNA is synthesized by the bonding of nucleotides to the bases on the template strand of DNA
ribosomes move into the nucleus
rRNA associates with the ribosome
During translation, amino acid chain elongation occurs until __________.
the ribosome runs off the end of the mRNA strand
no further amino acids are needed by the cell
the polypeptide is long enough
all tRNAs are empty
the ribosome encounters stop codons in the mRNA
A virus infects a cell and randomly inserts many short segments of DNA, each containing a stop codon, throughout the organism's chromosomes. This will probably cause __________.
manufactured proteins to be short and defective
the DNA to break up into thousands of short segments
no bad effects, as long as the stop codons are not also inserted into tRNA
less protein production
incorrect pairing between mRNA codons and tRNA anticodons
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?
The tRNA with the polypeptide chain leaves the ribosome.
The tRNA with the single amino acid leaves the ribosome.
The amino acid moves over and bonds to the polypeptide chain.
The polypeptide chain moves over and bonds to the single amino acid.
A third tRNA with an amino acid joins the pair on the ribosome.
A particular _____ contains the information for making a specific polypeptide, but _____ can be used to make any polypeptide.
gene and mRNA ... a ribosome and tRNA
ribosome and mRNA ... a gene and tRNA
tRNA and ribosome ... a gene and mRNA
gene and ribosome ... tRNA and mRNA
gene and tRNA ... a ribosome and mRNA
What is the proper order of the following events in the expression of a eukaryotic gene?
2. RNA processing
2, 1, 3
2, 3, 1
1, 3, 2
1, 2, 3
3, 2, 1
Which one of the following processes takes place in the nucleus?
association of ribosomes to form polyribosomes
replication of mitochondrial DNA
synthesis of ribosomes
removal of introns from RNA
Which summary of protein synthesis is correct?
Messenger RNA is made on a DNA template by DNA polymerase, and then leaves the nucleus to be translated into proteins at the ribosomes.
Transfer RNAs line up on a ribosome, and amino acids bind to them with hydrogen bonds.
DNA exchanges its thymine units with uracil in polymerase. This activates polymerase, and it starts joining amino acids together.
DNA leaves the nucleus, goes to a ribosome, and catalyzes the polymerization of amino acids in a protein.
Messenger RNA is made on a DNA template, and then amino-acid-bearing transfer RNAs line up on it through codonanticodon pairing.
Mutations are __________.
changes in genes that ultimately cause genetic diversity
changes in the nuclear membrane
changes in the sugars of a DNA molecule
Causes of evolution
the result of new alleles
A geneticist found that a particular mutation had no effect on the polypeptide encoded by a gene. This mutation probably involved __________.
alteration of the start codon
insertion of one nucleotide
deletion of the entire gene
deletion of one nucleotide
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 might this have on the cell?
An amino acid will be missing from the protein product of this gene.
An amino acid will be missing from a variety of different proteins.
The entire amino acid sequence of this protein will be completely changed.
Many different proteins will contain an incorrect amino acid.
There is a very good likelihood that there will be an amino acid substitution in the protein product of the affected gene.
Ultraviolet (UV) radiation is damaging because it __________.
prevents DNA translation
inhibits protein synthesis
causes mutations in the DNA
deactivates the enzymes needed for DNA replication
prevents DNA transcription
Genetic mutations __________.
are most common in body parts that are used frequently
are always passed on to the next generation
can occur naturally without the addition of mutagens
are most common in body parts that are not used very often
are mainly caused by diseases associated with fetal development
The phage reproductive cycle that kills the bacterial host cell is a _____ cycle.
A prophage is a(n) __________.
prion that has been integrated into a bacterial cell's chromosome
viral genetic material that has been incorporated into a bacterial cell's chromosome
virus that infects bacteria
type of retrovirus
Why are insects common vectors of plant viruses?
Insects are the only organisms small enough to transmit plant viruses.
Insects often eat plant parts, causing injury and sites for viruses to get through the protective outer layer of plants.
Insects are immune to viruses.
Insects are resistant to genetic engineering.
Insects will spend their whole lives on a single plant.
In enveloped RNA viruses, the viral enzyme that produces copies of the RNA is probably most similar to which eukaryotic enzyme?
Given the data in Figure 10.29, what would happen if flu vaccines were given at the beginning of summer instead of the start of winter?
Elderly that received the summer flu vaccine would have significantly fewer hospitalizations and less morbidity during the summer than those who did not get the vaccine.
Elderly that received the summer flu vaccine would have significantly more hospitalizations and morbidity during the summer than those who did not get the vaccine.
Elderly that received the summer flu vaccine would have significantly fewer hospitalizations and less morbidity during the summer and following winter than those who did not get the vaccine.
Elderly that received the summer flu vaccine would have significantly fewer hospitalizations and less morbidity during the winter than those who did not get the vaccine.
There would be no significant difference in summer or winter hospitalizations and morbidity between elderly who received the summer vaccine and those who did not get the vaccine.
How do retroviruses, such as HIV, differ from other viruses?
They contain the enzyme reverse transcriptase.
They can reproduce only inside living cells.
They have much simpler reproductive cycles than other RNA viruses.
They contain DNA that is used as a template to make RNA.
They contain nucleic acids that code for proteins.
What is a major difference between prions and viruses?
Prions use enzymes involved with transcription or translation to assist their replication.
Prions lack genetic material such as RNA or DNA.
Prion-related infections are curable.
Prions only infect plants.
Prions are larger than viruses.
Which of the following is an "emerging virus" that has a direct impact on human health?
tobacco mosaic virus
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