ch 12 bio
About ______ of the human genome consists of exons, while ______ of the genome consists of introns.
1 24
Click and drag on elements in order Place these steps in the correct order that they occur in eukaryotic protein synthesis, beginning with the first step at the top of the list.
1 DNA 2introns 3 transcipts leaves 4 binds 5 mRNA 6 COMPLETES
Place these steps in the correct order that they occur in eukaryotic protein synthesis, beginning with the first step at the top of the list.
1 DNA 2 introns 3 leaves 4 binds 5 mRNA 6 completed
Put the following steps in the order that they occur during the beginning of translation. Start with the first step at the top of the list.
1 mRNA 2 larger 3 tRNA binds 4 2nd 5 rib
Place in order the steps of translation starting with the first step at the top. Position 1 of 6 the ribosome releases the polypeptide incorrect toggle button unavailable
1 rRNA 2 rib moves 3 amino 4 rib encounters 5 rib disengages 6 rib releases
Place in order the steps of translation starting with the first step at the top.
1 rRna 2 rib moves 3 amino 4 rib encounters 5 rib disengages 6 rib releases
Click and drag on elements in order Put the steps of translation into their correct order.
1 small 2 tRNA binds 3 rib 4 tRNA in e sites
When making an mRNA transcript, RNA polymerase moves from
5' to 3' adding RNA nucleotides to the 3' end.
Transfer RNA (tRNA) carrying an amino acid binds to a ribosome at the ______.
A site
Select results of the addition of methyl and acetyl groups to histones during epigenetic modification.
Chromatin structure is disrupted. DNA is more accessible for transcription.
How does mRNA help protect the information contained in DNA?
The mRNA is made in the nucleus using DNA and then goes out into the cell to serve as an expendable copy.
When a stop codon is encountered during translation of a protein, which of the following occur?
The newly synthesized polypeptide is released. The ribosome complex disassembles.
An enhancer is
a binding site for eukaryotic activators that is distant from the promoter.
Which of the following best describes mRNA?
a copy of a gene used to produce a protein
Controls of eukaryotic gene expression that act on mRNA after it is produced include which of the following? Select all that apply.
alternative splicing gene silencing
Activating enzymes match the correct ______.
amino acid to its tRNA
In translation, a sequence of nucleotides is translated into a sequence of ______.
amino acids
The correct amino acid is joined to its tRNA by ______.
an activating enzyme
One end of tRNA binds an amino acid, while the other contains an anticodon that binds to ______.
an exposed complementary codon on the mRNA
What did biologists use to help them determine which amino acid matched to a codon?
artificial mRNA trial and error
Select all of the methods of post-transcriptional control in eukaryotic gene expression.
availability of different types of RNA modification of the protein
Which of the following are controls of eukaryotic gene expression that regulate whether transcription can occur? Select all that apply.
availability of different types of transcription factors modification of chromatin structure
Choose the order that correctly describes the transfer of information in living organisms according to the central dogma.
DNA to RNA to protein
Transcription terminates when RNA polymerase arrives at a ______ at the end of a gene.
"stop" signal
BLANK are the sections of DNA that encode the amino acid sequence of a polypeptide, whereas BLANK are noncoding sections of DNA that must be removed during processing of the mRNA transcript.
EXON INTRONS
Select molecules that must be present for the initiation complex of transcription to form in eukaryotic cells.
RNA polymerase basal transcription factors
When making mRNA using DNA, ______.
RNA polymerase pairs up an RNA nucleotide with a DNA nucleotide
In eukaryotes, basal transcriptions factors help recruit ______ to the promoter to form the ______ complex and allow transcription to occur at a basal rate.
RNA polymerase; initiation
The promoter region on the DNA is the site where ______ binds to initiate ______.
RNA polymerase; transcription
How are activators able to interact with the initiation complex even though they bind to distant enhancer sites?
The DNA bends, bringing the activator into contact with the initiation complex.
Why is the process of creating a protein from mRNA called translation?
The chemical language changes from the nucleotides of RNA to amino acids in the protein.
Select the two ways that siRNAs can achieve gene silencing.
binding to mRNA molecules with a complementary sequence, blocking translation destroying the mRNA that has the complementary sequence
The correct amino acid is added to a growing polypeptide when an anticodon on the tRNA ______.
binds to a matching codon on the mRNA
To begin transcription, RNA polymerase
binds to one strand of the DNA double helix that contains a promoter-site sequence it recognizes.
Select all of the following that are true about transfer RNA (tRNA).
contains an anticodon on one of its loops has an amino acid attachment site at its 3' end has a folded, three-loop structure
Select all of the following that are true about an anticodon.
determines which amino acid will attach to a tRNA molecule complementary to a codon
In RNA processing, ______ are removed from the primary RNA transcript to form the ______.
introns; mature mRNA
In eukaryotes, coactivators and mediators act to
modulate the effect of specific transcription factors.
In eukaryotic gene transcription, a(n) ______ is the binding site for activators and is located ______ the promoter.
enhancer; distant from
In eukaryotes, transcription can be increased when activators bind to ______ and interact with the ______.
enhancers; initiation complex
Select all of the controls of eukaryotic gene expression that occur before transcription.
epigenetic modification initiation of transcription
Alterations to DNA or histones that affect gene expression but do not alter the sequence of DNA nucleotides are called
epigenetic modification.
The information specifying hereditary traits is encoded in blocks of DNA called
genes.
At its lowest level of organization, DNA is packaged into nucleosomes that consist of DNA and
histone proteins.
At its lowest level chromosomes are organized into nucleosomes made up of ______.
histones DNA
A primary transcript of mRNA ______.
includes both exons and introns
Specific transcription factors can bind to the initiation complex to ______.
increase the level of gene transcription
in gene expression
information in DNA directs the synthesis of a specific polypeptide
In eukaryotes, transcription factors are proteins that
interact with RNA polymerase.
Sections of a eukaryotic gene that do not encode polypeptides and that are removed during RNA processing are called ______.
introns
The subunits of a ribosome ______.
nest together to form a functional unit
In eukaryotes, DNA is wound around eight histone proteins to form a
nucleosome.
During translation the sequence of ______ is translated into a sequence of ______.
nucleotides; amino acids
Clusters of ribosomes translating mRNA are called
polyribosomes.
Following transcription the BLANK RNA transcript contains the entire gene, both introns and exons.
primary
The unprocessed mRNA transcript is called a ______ transcript.
primary RNA
In a ______ cell, a gene can be translated as it is being transcribed.
prokaryotic
The site on the DNA where RNA polymerase binds at the start of transcription is called the ______.
promoter
Starting at the ______ located at the beginning of a gene, RNA polymerase synthesizes ______
promoter; an mRNA transcript of the DNA
In what cellular process are messenger RNA, transfer RNA, ribosomal RNA, and silencing RNA used?
protein synthesis
The components of ribosomes are ______.
proteins and rRNA
Choose the steps of translation from those given.
rRNA within a ribosome binds to mRNA amino acids are added to a growing polypeptide chain the ribosome moves along the mRNA
The type of RNA that is a component of ribosomes is
rRNA.
A region of ______ found in the small subunit of the ribosome corresponds to the leader region of all genes and causes the ______ to bind correctly to the ribosome during initiation of translation.
rRNA; mRNA
Gene control in a multicellular organism functions to ______.
regulate the body as a whole
What type of chemical modification of histones can block transcription by causing the DNA to condense further?
removal of methyl groups
Select all the types of RNA used in protein production.
ribosomal RNA (rRNA) messenger RNA (mRNA) transfer RNA (tRNA)
The site of protein synthesis is the ______.
ribosome
The binding of ______ to mRNA molecules with a complementary sequence blocks translation and silences the gene.
siRNA
What type of RNA can regulate gene expression by preventing translation?
small interfering RNA
What can bind to the initiation complex to achieve more regulation of transcription?
specific transcription factors
The synthesis of a polypeptide is terminated when a ______.
stop codon is reached on the mRNA
Transcription refers to the process of
synthesizing RNA from a DNA template.
The attached image shows a(n) ______, an important part in the process of translation.
tRNA
The three sites on the ribosome that form dents or pockets are the sites where _____ binds.
tRNA
What type of RNA brings amino acids to the ribosome during translation?
tRNA
In this diagram of a(n) ______ molecule, letter A represents the ______, and letter B represents the ______.
tRNA; amino acid attachment site; anticodon
During transcription, RNA polymerase binds to one strand of DNA, which is called the ______ strand, and adds complementary nucleotides to the DNA, using ______ instead of thymine.
template; uracil
What is the same in practically all organisms?
the genetic code
What process results in the production of messenger RNA?
transcription
Precise control of the level of transcription in eukaryotes is achieved by the formation of a
transcription complex.
In eukaryotes, transcription is more complex and requires not only RNA polymerase but also ______ that interact with RNA polymerase.
transcription factors
The mRNA product of ______ is used by ribosomes to produce a polypeptide in ______
transcription; translation
The mRNA product of ______ is used by ribosomes to produce a polypeptide in ______.
transcription; translation
In gene expression, the production of a protein from RNA is called ______.
translation
How many subunits make up a ribosome?
two
Given a codon on mRNA of AUG, the BLANK on the tRNA molecule would be UAC.
ANTICODON
Given the mRNA codon sequence UAG the anticodon sequence would be ______.
AUC
The codon ______ is the start codon on the mRNA and will bind to a tRNA anticodon with the sequence ______.
AUG; UAC
Select the correct statements about the process of translation.
At translation initiation, mRNA binds to the small subunit of a ribosome, and then the large subunit binds to form a complete ribosome. The sequence of the mRNA determines what tRNAs will bind, and what amino acids will be added to the polypeptide. The tRNA bound at the P site moves to the E site as the ribosome moves to the next codon. The ribosome moves down the mRNA three nucleotides at a time.
What statement characterizes gene regulation in multicellular organisms?
Genes are transcribed at the right time during development in a prescribed order.
What is the result of DNA methylation during epigenetic modification?
Genes are turned off.
Select the correct statement about genes in prokaryotic and eukaryotic cells.
In prokaryotic cells, genes occur as unbroken sections of DNA, while in eukaryotic cells, genes have interrupting segments called introns.
In eukaryotes, why do primary RNA transcripts have to be processed to form mature mRNA transcripts?
Introns have to be removed before translation
Given the mRNA nucleotide sequence AUGGAUAAAUGGUGA, choose the amino acid sequence it would produce.
Methionine - Aspartate - Lysine - Tryptophan - Stop
Select all of the following that are true about the genetic code.
Most amino acids are specified by more than one codon. Some codons do not specify an amino acid but rather signal translation to stop.
Given the mRNA nucleotide sequence CCCAACAGCGAGGCC, choose the amino acid sequence it would produce.
Proline - Asparagine - Serine - Glutamate - Alanine
In gene silencing, what type of molecule may act after transcription to affect whether a particular mRNA is translated?
RNA
The silencing of genes that are complementary to double-stranded RNA is called
RNA interference.
What releases newly synthesized mRNA when it encounters a "stop" signal at the end of a gene?
RNA polymerase
Select all of the following that are steps leading to the production of a protein in eukaryotes.
The primary mRNA transcript is processed to form mRNA. DNA is transcribed into mRNA. tRNA carries amino acids to the ribosome.
Why can transcription and translation take place at the same time in prokaryotes?
There is no nuclear membrane to act as a barrier.
In translation, a codon is ______.
a group of three nucleotides that determine the amino acid to be added to a polypeptide
Over 50 different proteins and rRNA make up ______.
a ribosome
The initiation of translation begins when ______.
a ribosome recognizes the start sequence on mRNA and binds to it
Select components that can be involved in the eukaryotic transcription complex.
activators coactivators RNA polymerase basal transcription factors
Select all of the following that modify the rate of transcription in eukaryotes.
activators mediators coactivators
The primary method of epigenetic modification is the
addition of a methyl group to cytosine nucleotides.
Select modifications made to the primary RNA transcript in eukaryotes that protect the RNA from degradation.
addition of a poly-A tail addition of a 5' cap
Small interfering RNAs regulate gene expression
after transcription.
Alternative splicing of the exons of an RNA transcript ______.
allows the production of different proteins from the same gene
The removal of introns in the primary mRNA transcript and the joining of the remaining exons in different ways is called ______.
alternative splicing
During protein synthesis, transfer RNA ______.
brings amino acids to the ribosome
Epigenetic modification refers to the
chemical alteration of DNA or histones that affect gene expression
What are polyribosomes?
clusters of ribosomes translating an mRNA strand
The triplet of nucleotides in mRNA that determines the amino acid to be added to a polypeptide sequence is called a(n) ______.
codon
RNA polymerase transcribes DNA into mRNA using ______.
complementary base pairing rules
Select all of the following that describe genes in eukaryotes.
contain sections called exons that encode polypeptides have interrupting segments called introns
During translation the ______ is used to direct the synthesis of the protein by providing the directions taken from the DNA.
mRNA
When serving as an expendable copy of DNA, ______.
mRNA leaves the nucleus to be used for protein synthesis
Transcription is the process of creating a(n) ______ copy of a(n) ______.
mRNA; gene
Chemical modifications that affect condensation of genetic material
make genes more or less accessible to RNA polymerase.
What molecule brings the information from the DNA to the ribosomes for translation of the nucleotide sequence into the amino acid sequence of a polypeptide?
messenger RNA
What type of RNA conveys the information contained in a DNA sequence to the cytoplasm and directs the sequence of amino acids in a polypeptide?
messenger RNA
In the genetic code, each sequence of ______ nucleotides corresponds to a(n) _______.
three; amino acid
Artificial mRNA consisting of repeated nucleotides, such as UUUUUUUUUUUUU, were used ______.
to determine which codons correspond to which amino acids
In eukaryotes, why are the 5' cap and poly-A tail added to the primary RNA transcript?
to protect the RNA transcript from degradation
Which of the following correctly describes the purpose of mRNA?
to serve as expendable copy of a portion of DNA
In gene expression, the production of RNA from DNA is called ______.
transcription
RNA polymerase synthesizes mRNA during ______.
transcription
