ch 9
which of the following is a characteristic of double-stranded DNA?
2 nanometers in width 10 base pairs per turn 0.34 nanometers per base pair
Which of the following DNA sequences is complementary to 5' TAGAC 3'?
5' GTCTA 3'
According to Chargaff's rule, which of the following statements about double-stranded DNA is NOT true?
A + T = C + G
Which of the following DNA molecules is the most stable?
GCGTGCAC CGCACGTG
Unzipping the DNA helix
Helicase
Which is the correct order of events when a protein is made in the process of translation?
Initiation, elongation, termination
Final binding of nicks in DNA during synthesis and repair
Ligase
Synthesizing an RNA primer
Primase
The processes of transcription and translation differ between prokaryotes and eukaryotes in the following way:
Prokaryotes transcribe and translate simultaneously.
Which type of plasmids confer the ability of an organism to survive treatment by antibiotics?
R factors
Before the lagging strand can begin assembling new DNA nucleotides, which of the following must occur?
RNA primase constructs a short RNA primer.
If one strand of DNA contains the bases ACAGT, what would be the complementary bases on the mRNA strand?
UGUCA
What happens when a hairpin loop forms in mRNA?
The RNA polymerase and the mRNA dissociate from the DNA.
Repressible operons (such as the arg operon)
are usually in the "on" mode
Which of the following is a true statement concerning protein synthesis in eukaryotic organisms?
Transcription occurs in the nucleus and translation occurs in the cytoplasm.
Introns are removed and exons are spliced together
before translation
Nucleotides are the building blocks of
both DNA and RNA.
DNA polymerase
can only add nucleotides in a certain direction.
are groups of three bases in mRNA that specify one amino acid in the amino acid chain
codons
Which of the following require physical contact between two bacterial cells for DNA transfer?
conjugation
The following pertain to ribosomes during protein synthesis except
contain codons within their rRNA molecules
What binds with an inactive repressor to make an active repressor?
corepressor
Which pentose sugar is found in DNA?
deoxyribose
A nucleotide is oriented 5' or 3' depending on the location of the _______ on the strand of DNA.
deoxyribose carbons
The DNA of a chromosome is ___-stranded.
double
One bacterial chromosome replicates to become two chromosomes with
each made of one strand of DNA from the original chromosome and one newly synthesized strand.
In eukaryotic cells, gene expression is regulated in response to ___ stimuli such as nutrient and toxin levels, and also during growth and ___ .
environmental, development
Proteins that remove incorrect bases and replace them with correct ones are termed ______ repair enzymes.
excision
The process in which mutations are removed and replaced with the correct bases is called
excision repair
The purpose of RNA synthesis is to provide a new copy of DNA as the original strand deteriorates over time
false
The trp operon consists of __________ structural gene(s).
five
A sequence of bases within a gene that will be transcribed, but removed from the transcript prior to translation is a/an
intron
Eukaryotic mRNA contains non-coding regions called ______.
introns
Which DNA sequences are found within a gene but do not encode the protein specified by that gene?
introns
are DNA sequences found within a gene that do not encode the protein corresponding to the gene.
introns
When a repressor binds to the operator site on DNA
it blocks RNA polymerase and mRNA synthesis.
The lac repressor binds to what site within the lac operon?
lacO
What molecule is synthesized as a copy of a gene from the DNA template strand?
mRNA
Which of the following types of RNA is the transcribed version of a structural gene in DNA, that is later read for translation into protein?
mRNA
The three types of RNA are
messenger, transfer, ribosomal
A ____ is the basic unit of DNA structure.
nucleotide
RNA is a chain of
nucleotides
Which of the following occurs first in transcription?
formation of a holoenzyme
addition or deletion of bases that changes the reading of mRNA codons
frameshift mutation
A segment of DNA encoding a protein or an RNA molecule is a
gene
The complete set of chromosomes and genes in an organism is referred to as the
genome
Which term represents all of the genetic information within a cell?
genome
Which is incorrect about inducible operons?
have genes turned off by a buildup of end product
The enzyme that unwinds a segment of the DNA molecule is
helicase.
is another term for genetics--the study of inheritance in living things.
heredity
dsDNA
herpesvirus
Eukaryotic chromosomes differ from prokaryotic chromosomes because only eukaryotes have
histone proteins chromosomes in a nucleus several to many chromosomes elongated linear, not circular, chromosomes
The initial transfer RNA occupies the __________ on the ribosome.
p site
The bond connecting amino acids is a(n) ____ bond.
peptide
A __________ is the physical expression of the genes present and can change depending upon what genes are turned "on."
phenotype
is a small circular segment of DNA found in the cytoplasm of bacteria that is capable of independent replication and usually contains nonessential genes.
plasmid
Hfr transfer involves all of the following except
plasmid gene transfer
Mutations that involve the addition, deletion or substitution of one or a few bases are referred to as _______ mutations.
point
Which of the following are parts of a nucleotide in DNA?
phosphate, nitrogenous base, deoxyribose sugar
The correct structure of DNA components can be presented as
phosphate-sugar-base.
Which process repairs DNA that has been damaged by ultraviolet radiation using visible light?
photoactivation
Donor and recipient bacterial cells are connected by the sex ___ during conjugation
pili
refers to the transfer of genes from donor to recipient microorganisms, where the recipient strain shows a change in genetic makeup at the end.
recombination
The ___ of the genetic code results in several codons encoding the same amino acid.
redundancy
___ RNA may exert control on several levels in both prokaryotes and eukaryotes.
regulatory
During semiconservative _____ the DNA is duplicated prior to binary fission.
replication
ssRNA
poliovirus
What must occur prior to cell division to ensure that each new cell has a complete set of DNA chromosome(s)?
replication
The site where the old DNA strands separate and new DNA strands will be synthesized is called the
replication fork
Transcription begins when RNA polymerase binds to the
promoter on DNA
DNA polymerases are responsible for
proofreading/repair. building the DNA chain.
The ___ protein is capable of repressing an operon.
repressor
The protein product of a repressor gene is the ___ which binds the operator to stop transcription.
repressor
Split genes
require spliceosomes to excise introns and then join exons.
DNA polymerase
requires a template for the synthesis of DNA. Correct
Which pentose sugar is found in RNA?
ribose
Protein synthesis occurs on ____.
ribosomes
DNA replication is said to be
semi-conservative
During ___ DNA replication, the newly made double helices are composed of one parent template and one newly synthesized strand.
semiconservative
___ mutations in DNA are caused by random mistakes in replication and not known to be influenced by any mutagenic agent.
spontaneous
random change in the DNA arising from errors in replication that occur without a known cause
spontaneous mutation
Which are components of an operon in a sequence of DNA?
structural genes, operator
changing of single base in the DNA code that may result in the placement of a different amino acid
substitution mutation
The RNA molecules that carry amino acids to the ribosomes during protein synthesis are called
tRNA
During replication, each parent DNA strand serves as a __________ for synthesis of new DNA strands.
template
The Rho protein is involved in the __________ stage of transcription.
termination
Full induction of the lactose operon requires
that lactose be present without glucose.
In some degradative pathways, in the absence of an inducer (e.g., arabinose)
the activator protein can't bind to DNA, and RNA polymerase can't bind to the promoter site. Correct
Translation is characterized by
the blueprint of the RNA molecule used to bind amino acids together to form proteins.
Two different mechanisms for copying the DNA strands are used because
the strands are oriented in opposite directions. Correct
The process of transcription is similar to
the synthesis of the leading strand during DNA replication.
The term , ___ or codon, is a sequence of 3 nucleotides in DNA that encodes an amino acid.
triplets
In the presence of tryptophan, tryptophan binds to the
trp repressor.
If you know the sequence of nucleotides in mRNA, you can deduce the DNA sequence it was transcribed from.
true
Unlike DNA, RNA is usually single-stranded.
true
In RNA, which nitrogenous base pairs with adenine?
uracil
The nitrogenous base thymine is only found in DNA, while ___ is only found in RNA.
uracil
Vancomycin-resistant enterococci (VRE) arise when, through genetic transfer, a MRSA strain acquires the operon _____ located within a _______.
vanA, transposon
Put the following steps in order describing the viral process of a retrovirus, such as HIV.
viral RNA ssDNA dsDNA new viral RNA
A mechanism that blocks transcription
will block the production of mRNA.
The process of __________ always results in the same genes being transferred between bacteria.
specialized transduction
Supercoiling
Gyrase
retrovirus
HIV
In a chromosome, the DNA is composed of ______ strands.
2
If the codon GGU is positioned in the A site of the ribosome, which of the following will occur
A tRNA with the anticodon CCA will deliver its amino acid to the site
Which component of DNA determines the 3' and 5' ends of the strands?
Carbons in the deoxyribose sugar
Which of the following best describes transcription?
DNA -> RNA
Which best describes the flow of genetic information in a cell?
DNA encodes RNA which encodes protein
The enzyme that travels along the leading strand assembling new nucleotides on a growing new strand of DNA is
DNA polymerase
Removing RNA primers, replacing gaps between Okazaki fragments with correct nucleotides, repairing mismatched bases
DNA polymerase I
Adding bases to the new DNA chain, proofreading the chain for mistakes
DNA polymerase III
The flow of genetic information in a cell is a process starting with ___ which encodes ___ which encodes protein
DNA, RNA
Genetic inheritance in microorganisms is best defined by which term?
Heredity
in bacterial conjugation, which type of donor has the fertility factor integrated into the chromosome?
Hfr
DNA polymerase ____ is the main enzyme involved in the building of the new DNA chain, whereas DNA polymerase ____ is involved mostly with removing the primers and repairing damaged DNA.
III/I
Which of the following is correct regarding sigma factor?
It recognizes the promoter region.
On one of the strands of bacterial DNA, the new complementary strand is synthesized discontinuously into small pieces of DNA called
Okazaki fragments.
What three components make up RNA structure?
Phosphate, nitrogenous base, ribose sugar
The main enzyme responsible for transcription is
RNA polymerase
Which of the following are functions of RNA polymerase?
Synthesizes an RNA molecule from DNA template Unwinds the DNA so that transcription can take place
After mRNA is made, what generally occurs?
The mRNA is translated to protein.
What is the purpose of the Ames test?
To determine the carcinogenic potential of a chemical
Transcription is characterized by
a messenger RNA molecule synthesized from the DNA molecule in the nucleus.
Genetic transfer of ______ to a methicillin-resistant Staphylococcus aureus (MRSA) strain produces vancomycin resistant enterococci (VRE).
a transposon containing the vanA operon
If an organism lost the ability to make primase, what would it be unable to do?
add a short sequence of complementary RNA to the existing DNA strand Correct
The two strands of the DNA molecule are
antiparallel
Synthesis of mRNA is
in the 5' to 3' direction with new nucleotides being added to the 3' end of the mRNA molecule
In the absence of tryptophan, the trp repressor is
inactive and cannot bind to the operator.
result from exposure to known mutagens, which are primarily physical or chemical agents that damage DNA
induced mutation
If the wild type DNA sequence reads THE CAT ATE THE BIG RAT, what type of mutation would change the sequence to THE CAT ATE THE BAG RAT?
missense
The mechanisms of ___ transformation involve genes that can regulate cellular genomes and control the onset of cell division.
oncogenic
A(n) ______ is a cluster of genes that perform related functions found in ______
operon; prokaryotes Correct
Coordinated sets of genes that are regulated as a single unit are referred to as ______
operons
What component of RNA is different from one individual (or one bacterium) to the next?
order of nitrogenous bases
The site on a chromosome where DNA replication begins is called the ____ of replication.
origin
What usually terminates the process of translation?
presence of a stop codon on mRNA
Translation of mRNA into protein begins before transcription is complete in
prokaryotes only
are able to shift from one part of the genome to another.
transposons
The process of synthesizing RNA from a DNA template is
transcription
involves the transfer of DNA via bacteriophages.
transduction
Which of the following is not true of conjugation?
transfers genes for a polysaccharide capsule
Which gene transfer method involves the uptake of free DNA by competent bacterial cells?
transformation
"Jumping genes" are known as
transposons