Ch.9
Uracil, the nitrogenous base unique to RNA molecules, pairs with the nitrogenous base ___
Adenine
Which of the following are true of RNA viruses compared to DNA viruses?
Enter host cell in RNA form Smaller genomes Virus cycle occurs in cytoplasm
True or false: A mutation is an alteration in the DNA sequence or content of a cell that is passed on when the cell divides.
True
True or false: Several codons code for the same amino acid, which is called the redundancy of the code.
True
Transduction occurs through
bacteriophage
Any nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code is a nitrogenous ____
base
The three types of RNA are ___RNA, ____RNA, and _____RNA.
mRNA tRNA rRNA
A ___ mutation changes an amino-acid-producing codon into a stop codon, leading to premature termination of a protein.
nonsense
Any alteration in DNA that occurs as a consequence of exposure to chemical or physical mutagens is a(n) mutation.
induced
Transcription of the structural genes of the lac operon will be inhibited when
lactose concentration is low and glucose concentration is high.
Transcription of the structural genes of the lac operon will be greatest when
lactose is present in high concentrations but glucose is absent.
A ___ is the basic unit of DNA structure.
nucleotide
The basic unit of DNA structure is the
nucleotide
Several DNA viruses are known to be initiators of cancers and are thus termed
oncogenic
Which viruses insert their DNA into the host genome increasing the risk of cancer?
Herpesvirus Hepatitis B virus
In bacterial conjugation, which type of donor has the fertility factor integrated into the chromosome?
Hfr
Which are components of an operon in a sequence of DNA?
operator structural genes
Gene expression in prokaryotes is regulated through _______.
operons
Prokaryotic DNA is arranged into systems called
operons
The site on a chromosome where DNA replication begins is called the ___ of replication.
origin
The place where DNA replication is initiated is called the ______.
origin of replication
An enzyme that is named for its ability to build strands of DNA is DNA ________.
polymerase
RNA polymerase binds to the ____ region to initiate transcription.
promoter
DNA polymerases are responsible for
proofreading/repair. building the DNA chain.
In DNA, a purine always combines with
pyrimidine
Which of the following types of RNA delivers the amino acids to the growing peptide chain in translation?
tRNA
The region of DNA that signals the end of an RNA transcript is the ____ sequence.
termination
Which best describes the flow of genetic information in a cell?
DNA encodes RNA which encodes protein
Genetic inheritance in microorganisms is best defined by which term?
Heredity
Which term, synonymous with codon, describes a trinucleotide sequence coding an amino acid in DNA?
Triplet
Which of the following are physical, as opposed to chemical, agents that can cause mutations?
X-rays Ultraviolet light
The _____ , or continuous, strand is replicated without segments during DNA replication
leading
A DNA nucleotide is composed of a(n) , a(n) sugar, and a(n) base.
phosphate deoxyribose nitrogenous
Mutations that involve the addition, deletion or substitution of no more than a few bases are referred to as ___ mutations.
point
DNA _______ is the enzyme responsible for building strands of DNA.
polymerase
Two subunits of the ____ come together to perform protein synthesis.
ribosome
Which type of organisms have their DNA arranged into operons?
Prokaryotes
RNA polymerase binds to which region of DNA to begin transcription?
Promoter
The first three events of translation in the correct order are ____ ,_____ ,_____ followed by protein folding and processing.
initiation elongation termination
The newly forming DNA strand that is discontinuously replicated in segments (Okazaki fragments) is called the ___ strand.
lagging
The newly forming DNA strand that is discontinuously replicated in segments (Okazaki fragments) is called the _____ strand.
lagging
The final sealing of nicks in a newly synthesized DNA strand is catalyzed by the enzyme __
ligase
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
In protein synthesis, eukaryotic and prokaryotic cells show similarities in all of the following EXCEPT the
number of proteins encoded on a single mRNA. use of formyl-methionine as the first amino acid.
A ________ serves as the vector for transduction in bacteria.
phage
Mutations that involve the addition, deletion or substitution of one or a few bases are referred to as _______ mutations.
point
The enzymes responsible for building the DNA strand, proofreading newly produced DNA strands, and removing the RNA primer are DNA ____ I and III.
polymerase
In DNA, adenine pairs with _____ , whereas cytosine pairs with _____
thymine guanine
In DNA, adenine pairs with _____, whereas cytosine pairs with _____
thymine guanine
Which type of RNA comprises ribosomal subunits?
rRNA
Which strand is replicated discontinuously in segments during DNA replication?
The lagging strand only
Which is the correct order of events in transcription?
1. initiation 2. elongation 3. termination
Guanine and ______ are purine bases found in DNA.
Adenine
How many replication forks are formed from opening a section of a circular DNA molecule during replication?
2
In a chromosome, the DNA is composed of ______ strands.
2
DNA polymerase ___ is the enzyme responsible for building the DNA strand.
3
DNA polymerase ______ is the enzyme responsible for building the DNA strand.
3
Nucleotides can only be added to the ____ end of a growing chain.
3
All new DNA strands are synthesized from
5' to 3'
If a codon of mRNA reads 5'-UUG-3', the tRNA that delivers the amino acid to this location during translation will have an anticodon of 3'-_____-5'.
AAC
Which of the following are parts of a nucleotide in DNA?
Phosphate Nitrogenous base Deoxyribose sugar
Genes are made up of ______, a macromolecule made up of nucleotides.
DNA
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
The enzyme involved in replicating a new DNA strand is DNA polymerase _____, and DNA polymerase _____ is involved in removing the RNA primer, closing gaps, and repairing mismatched bases.
III, I
How does RNA differ from DNA in bacteria and eukaryotes?
In RNA, uracil replaces thymine RNA is single-stranded
Where are the chromosomes of yeast cells located?
In the nucleus
___ operons are usually turned on by the substrate of the enzyme for which the structural genes code.
Inducible
Which type of operon is typically in the "off" position until the appropriate substrate is present?
Inducible operon
Which is the correct order of events when a protein is made in the process of translation?
Initiation, elongation, termination
Which strand is replicated continuously without segments during DNA replication?
Leading
Which enzyme completes the final sealing of nicks in a newly synthesized DNA strand?
Ligase
Which of the following are chemicals that can cause mutations?
Nitrous acid Ethidium bromide Acridine dyes
In replication of DNA, the lagging strand is replicated in a discontinuous manner forming _____ fragments.
Okazaki
_____ fragments are formed during DNA replication of the lagging strand.
Okazaki
Gram-positive cells conjugate and transfer genetic material through which component?
Proteins activated during cell adhesion
The large enzyme complex involved in synthesizing RNA from a DNA template is called ___ ____
RNA polymerase
The large enzyme complex involved in synthesizing RNA from a DNA template is which of the following?
RNA polymerase
The main enzyme responsible for transcription is
RNA polymerase
Which are parts of the lactose operon?
Structural locus Regulator Control locus
What region of DNA signals the end of a RNA transcript?
Terminator
What is the purpose of the Ames test?
To determine the carcinogenic potential of a chemical
What are the two stages needed for protein synthesis?
Transcription Translation
___ and ____ are the two stages involved in protein synthesis.
Transcription Translation
Which of the following are functions of RNA polymerase?
Unwinds the DNA so that transcription can take place Synthesizes an RNA molecule from DNA template
In RNA, which nitrogenous base pairs with adenine?
Uracil
Unlike DNA, RNA contains the nitrogenous base ___
Uracil
The purine nitrogenous bases found in DNA are guanine and
adenine
The purine nitrogenous bases found in DNA are guanine and _____
adenine
The four nitrogenous bases in DNA are ___ ,_____ ,_____ , and _____.
adenine guanine cytosine thymine
The nitrogenous bases found in DNA include:
adenine, cytosine, guanine, thymine
The ___ of a tRNA is complementary to a ____ of mRNA.
anticodon codon
The ____ of a tRNA is complementary to a ____ of mRNA.
anticodon codon
Plasmids can be found in both ___ and ____ .
bacteria fungi
Plasmids are found in which type(s) of organisms?
bacteria and fungi
DNA polymerase III is responsible for:
building the DNA chain
Viral DNA inserted into the host genome may cause the transformation of the host cell into a ___cell.
cancer
A ____ is a discrete cellular structure composed of a neatly packaged DNA molecule.
chromosome
Donor and recipient bacterial cells are connected by the sex pilus during
conjugation
Which of the following is NOT a type of RNA?
dRNA
Pentose sugar found in DNA
deoxyribose
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 flow of genetic information in a cell is a process starting with ____ which encodes _____ which encodes protein.
dna rna
The DNA of a chromosome is ____ -stranded.
double
Transcription involves initiation,____ , and termination.
elongation
The replication ____ is the Y-shaped point on a replicating DNA molecule where the DNA polymerase is synthesizing new strands of DNA.
fork
A(n) ______ is a sequence of DNA nucleotides that codes for one functional protein or RNA.
gene
Control mechanisms ensure that _____ are active only when their products are required.
genes
The complete set of chromosomes and genes in an organism is referred to as the ___
genome
During eukaryotic protein synthesis, ______ ribosome(s) are used to translate mRNA that contains ______ gene(s).
many, one
The RNA form that contains the transcribed code for a protein from the original DNA strand is ____ RNA.
messenger
An organism that has a mutation is called a
mutant
The ___________ bases are either purines or pyrimidines.
nitrogenous
The ____ of the genetic code results in several codons encoding the same amino acid.
redundancy
the ___ is the gene that codes for a protein capable of repressing the operon.
regulator
During semiconservative ______ the DNA is duplicated prior to binary fission.
replication
What must occur prior to cell division to ensure that each new cell has a complete set of DNA chromosome(s)?
replication
Retroviruses contain the enzyme
reverse transcriptase
The pentose sugar found in RNA is
ribose
Which pentose sugar is found in RNA?
ribose
RNA virus genomes are usually than DNA virus genomes.
smaller
___ mutations in DNA are caused by random mistakes in replication and not known to be influenced by any mutagenic agent.
sponetnous
The ___ codon AUG of mRNA is associated with the tRNA anticodon UAC and the amino acid methionine.
start
The ____ codon AUG of mRNA is associated with the tRNA anticodon UAC and the amino acid methionine.
start
The mRNA sequence AUG, specifying the first amino acid in protein sequences, is called the ___ codon.
start
The RNA type that transfers amino acids to the growing peptide chain in translation is ____ RNA.
transfer
During the process of ___ a competent bacterial cell may accept soluble DNA from the surrounding environment.
transformation
The term ___ , or codon, is a sequence of 3 nucleotides in DNA that encodes an amino acid.
triplet
The nitrogenous base thymine is only found in DNA, while _____ is only found in RNA.
uracil
Which nitrogenous base is found in RNA but not found in DNA?
uracil