BIOL224 Exam 3 MultChoices Flashcards
Which of the following enzymes involved in DNA replication is unique to eukaryotes?
helicase
ligase
telomerase
DNA polymerase
telomerase
Which of the following statements about base pairing in DNA is incorrect?
Purines always base pairs with pyrimidines.
Base pairing occurs at the interior of the double helix.
Adenine binds to guanine.
Base pairs are stabilized by hydrogen bonds.
Adenine binds to guanine.
Which of the following is not found within DNA?
thymine
phosphodiester bonds
amino acids
complementary base pairing
amino acids
Which of the following types of RNA codes for a protein?
tRNA
dsRNA
rRNA
mRNA
mRNA
During elongation in translation, to which ribosomal site does an incoming charged tRNA molecule bind?
E site
P site
A site
B site
A site
According to the central dogma, which of the following represents the flow of genetic information in cells?
DNA to protein to RNA
RNA to DNA to protein
protein to DNA to RNA
DNA to RNA to protein
DNA to RNA to protein
When the ribosome reaches a nonsense codon, which of the following occurs?
a methionine is incorporated
the A site binds to a charged tRNA
a peptide bond forms
the polypeptide is released
the polypeptide is released
Which of the following is the name of the three-base sequence in the mRNA that binds to a tRNA molecule?
codon
anticodon
P site
CCA binding site
anticodon
The noncoding, repetitive sequences at the end of eukaryotic chromosomes are called which of the following?
forks
lagging strands
bubbles
telomeres
telomeres
During bacterial DNA replication, which of the following holds open the replication bubble?
single-strand binding proteins
helicases
primers
DNA polymerases
single-strand binding proteins
One strand of DNA runs from 5′ to 3′ and the opposing strand runs 3′ to 5′, meaning that the strands are oriented in which way?
conservative
antiparallel
helical
semiconservative
antiparallel
Which of the following correctly explains why DNA replication is described as semiconservative?
Each daughter strand contains one old strand and one new strand.
The nucleotides used in replication contain old and new components.
The nucleotides used in replication are recycled multiple times.
Each daughter strand contains two new strands.
Each daughter strand contains one old strand and one new strand.
A DNA nucleotide contains which of the following?
a ribose sugar and a nitrogenous base
a ribose sugar, a phosphate, and a nitrogenous base
a deoxyribose sugar, a phosphate, and a nitrogenous base
a deoxyribose sugar and a nitrogenous base
a deoxyribose sugar, a phosphate, and a nitrogenous base
Which of the following is a name for nitrogenous bases with a double-ring structure?
nucleotides
purines
pyrimidines
nucleosides
purines
Telomeres found in which of the following?
animal cells only, not in unicellular organisms
fungal, protist, plant, and animal chromosomes
microbes only, including all domains
all microbes
fungal, protist, plant, and animal chromosomes
Which of the following best describes the direction in which lagging strands are added?
in the 3′ to 5′ or 5′ to 3′ direction
as 5′ to 3′ Okazaki fragments in an overall 5′ to 3′ direction only
in variable directions depending on the species
as 5′ to 3′ Okazaki fragments in an overall 3′ to 5′ direction only
as 5′ to 3′ Okazaki fragments in an overall 3′ to 5′ direction only
During DNA replication, the lagging strand is formed from which of the following?
helicases
single strand binding proteins
leading strands
Okazaki fragments
Okazaki fragments
DNA polymerase adds DNA nucleotides in which of the following direction(s)?
in the 3′ to 5′ direction and in 5′ to 3′ direction
in the 3′ to 5′ direction only
in the 5′ to 3′ direction on one strand and in the 3′ to 5′ direction on the complementary strand
in the 5′ to 3′ direction only
in the 5′ to 3′ direction only
Which of the following conditions leads to maximal expression of the lac operon?
lactose absent, glucose absent
lactose present, glucose present
lactose absent, glucose present
lactose present, glucose absent
lactose present, glucose absent
Which process produces an RNA copy of a DNA molecule?
transcription
replication
transformation
translation
transcription
Which of the following correctly describes events that occur during transcription?
RNA polymerase binds to the core enzyme.
RNA polymerase binds to the operator.
RNA polymerase binds to the promoter
DNA polymerase binds to the site of initiation.
RNA polymerase binds to the promoter
Which of the following is not a difference between DNA and RNA?
DNA is usually double stranded and RNA is usually single stranded.
DNA is used for shorter-term functions than RNA
RNA is usually less stable than DNA.
RNA contains uracil and DNA contains thymine.
DNA is used for shorter-term functions than RNA
Ribosomes are composed mostly of RNA.
True
False
True
Which of the following correctly describes uracil and where is it found?
It is a nitrogenous base found in DNA only.
It is a nitrogenous base found in DNA and RNA.
It is a nitrogenous base found in RNA only.
It is a nitrogenous base found only in nucleotides of molecules other than RNA and DNA.
It is a nitrogenous base found in RNA only.
Which of the following is the amino acid that appears at the N-terminus of all newly translated prokaryotic and eukaryotic polypeptides?
methionine
glycine
tryptophan
selenocysteine
methionine
Which sequences of eukaryotic genes code for proteins?
invariant
introns
the spliceosome
exons
exons
Stop codons are also known as which of the following?
nonsense codons
sense codons
antisense codons
missense codons
nonsense codons
A nucleic acid is purified from a mixture. The molecules are relatively small, contain uracil, and most are covalently bound to an amino acid. Which of the following was purified?
DNA
tRNA
mRNA
rRNA
tRNA
Which is the mechanism by which improper excision of a prophage from a bacterial chromosome results in packaging of bacterial genes near the integration site into a phage head?
conjugation
specialized transduction
generalized transduction
transformation
specialized transduction
Which of the following is an example of a frameshift mutation?
silent mutation
a deletion of a codon
missense mutation
deletion of one nucleotide
deletion of one nucleotide
The F plasmid is involved in which of the following processes?
transposition
conjugation
transformation
transduction
conjugation
Which of the following is a change in the sequence that leads to formation of a stop codon?
nonsense mutation
silent mutation
missense mutation
deletion mutation
nonsense mutation
The formation of pyrimidine dimers results from which of the following?
spontaneous errors by DNA polymerase
exposure to ultraviolet radiation
exposure to intercalating agents
exposure to gamma radiation
exposure to ultraviolet radiation
A base substitution that does not cause a change in the resulting polypeptide is called ______.
missense
silent
frameshift
nonsense
silent
What type of radiation frequently causes thymine dimers?
microwave
gamma
X-ray
ultraviolet
ultraviolet
A chemical mutagen that is structurally similar to a nucleotide but has different base-pairing rules is called a ________.
transposon
base analog
alkylating agent
intercalating agent
base analog
The phenotype of an organism that is most commonly observed in nature is called the ________.
wild type
conserved phenotype
normal one
mutant
wild type
A small DNA molecule that has the ability to independently excise from one location in a larger DNA molecule and integrate into the DNA elsewhere is called a ________.
base analog
transposon
F plasmid
intercalating agent
transposon
DNA is picked up from the environment during _______.
transduction
conjugation
transposition
transformation
transformation
The enzyme used in light repair to split thymine dimers is called ________.
ligase
photolyase
exonuclease
helicase
photolyase
Which of the following refers to the mechanism of horizontal gene transfer naturally responsible for the spread of antibiotic resistance genes within a bacterial population?
specialized transduction
transformation
generalized transduction
conjugation
conjugation
Conservative transposition occurs when the transposon is ________ and inserted elsewhere in the genome.
cloned
copied
inverted
completely removed
completely removed
Which mutagen would cause an AT pair in DNA to be converted to a GC pair?
nitrous oxide
2-aminopurine
X-rays
ethidium bromide
2-aminopurine