Gene Expression 1 Flashcards
A(n) __ can be broadly defined as a unit of heredity.
gene
Gene function either at the molecular level or at the level of traits is referred to as gene __.
expression
ncRNAs are RNAs that do not encode __.
polypeptides
The synthesis of an RNA copy of a gene is called:
transcription
DNA is ______ to produce mRNA, which is then ______ to produce proteins that determine the traits an organism expresses.
transcribed; translated
A unit of heredity is also known as a(n) ______.
gene
The term pre-mRNA is another name for the initial RNA ______.
transcript
What term refers to gene function at the level of traits or at the molecular level?
Gene expression
A gene that stores information for the production of a polypeptide is called a(n) __ gene.
structural
Genes that encode polypeptides are called protein-__ genes.
encoding
What is the function of mRNA?
It carries information from DNA to ribosomes.
During the process of __, an RNA copy of a gene is produced.
transcription
Gene expression occurs in two steps. First, the __ found in a cell is transcribed to produce __, which is then translated into __.
DNA, RNA, polypeptide
The process of synthesizing a specific polypeptide on a ribosome is known as:
translation
In eukaryotes, the RNA original transcript, called pre-__, must be modified in several ways to make it a functionally active mRNA.
mRNA
What do structural genes store?
Information to specify a polypeptide
The central dogma states that DNA is __ into mRNA, which is then __ into a polypeptide.
transcribed, translated
Messenger RNA carries information from the DNA to cellular components called __, which play a key role in the synthesis of polypeptides.
ribsosomes
The synthesis of an RNA copy of a gene is called:
transcription
In transcription, a(n) __ sequence is copied into a(n) __ sequence.
DNA, mRNA
An mRNA molecule is used to synthesize a specific polypeptide on a ribosome in the process of __.
translation
At the molecular level, a gene is an organized unit of ______ sequences that can be transcribed into RNA.
nucleotide
The term pre-mRNA is another name for the initial RNA ______.
transcript
Which of the following are products of nonstructural genes?
- polypeptides
- pre-mRNA
- messenger RNA
- transfer RNA
- ribosomal RNA
transfer RNA
ribosomal RNA
The central dogma of gene expression at the molecular level is comprised of two steps. These two steps are:
transcription of DNA into mRNA
translation of mRNA into a polypeptide
Transfer RNA translates the language of ______ into that of amino acids.
mRNA
What is the function of mRNA?
It carries information from DNA to ribosomes.
In the process of __, a DNA sequence is copied into an RNA sequence.
transcription
Ribosomal RNA is a component of ribosomes, which are the sites of:
translation
A gene is a unit of nucleotide sequences that enables a segment of DNA to be transcribed into __, which can then be translated to produce a polypeptide.
mRNA
While the transcription of structural genes produces mRNA that specifies a polypeptide, the transcription of nonstructural genes can produce two important products: __ RNA and __ RNA.
transfer, ribosomal
Which region of a structural gene signals the beginning of transcription?
promotor
Transfer RNA (tRNA) is needed to make what during translation?
Polypeptides
Transcription begins next to a site in DNA called the:
promoter
Messenger RNA carries information from the DNA to cellular components called __, which play a key role in the synthesis of polypeptides.
ribosomes
The __ is a DNA sequence that specifies the end of transcription.
terminator
__ RNA forms part of the cell structure that provides the site where proteins are synthesized.
R
The stages of transcription are called:
initiation, elongation and termination
At the molecular level, a gene is an organized unit of ______ sequences that can be transcribed into RNA.
nucleotide
During the initiation stage of bacterial transcription, the gene region called the __ functions as a recognition site for the sigma factor of RNA polymerase.
promoter
Which region of a bacterial gene signals the end of transcription?
Terminator
Which of the following events occur during the initiation stage of transcription?
- Sigma factor is released.
- DNA near the promoter is unwound to form an open complex.
- RNA polymerase binds to the promoter.
- The RNA transcript dissociates from the DNA.
DNA near the promoter is unwound to form an open complex.
RNA polymerase binds to the promoter.
The promoter of a gene signals the beginning of:
transcription
What is synthesized during the elongation stage of transcription?
RNA
What part of a gene signals the end of transcription?
Terminator
The DNA strand that is complementary to the RNA strand produced during transcription is called the __ strand.
template
Transcription occurs in three stages: initiation, __, and __.
elongation, termination
In E. coli, what protein recognizes the base sequence of the promoter and causes RNA polymerase to bind to the promoter?
Sigma factor
During which stage of transcription does RNA polymerase bind to the promoter?
Initiation
RNA polymerase synthesizes the RNA transcript during the __ stage of transcription.
elongation
In the coding strand, the __ in the DNA is replaced with __ in the mRNA.
thymine, uracil
The strand of DNA that is used by RNA polymerase during transcription is called the __ strand.
template
During the elongation stage of transcription, nucleotides bind to the template strand and are covalently connected in which direction?
5’ to 3’
During the initiation stage of bacterial transcription, the gene region called the __ functions as a recognition site for the sigma factor of RNA polymerase.
promotor
The sequence of a DNA template is 3’-GGTTCCTT-5’. What is the sequence of the RNA molecule that will be transcribed from this template strand?
5’-CCAAGGAA-3’
Which of the following events occur during the initiation stage of transcription?
- The RNA transcript dissociates from the DNA.
- Sigma factor is released.
- RNA polymerase binds to the promoter.
- DNA near the promoter is unwound to form an open complex.
RNA polymerase binds to the promoter.
DNA near the promoter is unwound to form an open complex.
During the termination stage of transcription, what happens when the RNA polymerase and the RNA transcript reach the terminator?
RNA polymerase dissociates from the DNA
In a double-stranded DNA molecule, what DNA strand has almost the exact same sequence of bases as the mRNA that is synthesized from that molecule? Note that the only exception in sequence is that thymine in that DNA strand is replaced with uracil in the RNA.
The coding strand
What RNA produced in eukaryotic transcription is the longest?
pre-mRNA
Before leaving the nucleus, pre-mRNA transcripts are modified by splicing, as well as the addition of
__ and __ to the ends of the mRNA.
caps, tails
During transcription, ribonucleotides are added to the
3’ end of the mRNA transcript
What sequence of RNA will be transcribed from a DNA template strand that is 5’-ACGTAAC-3’?
3’-UGCAUUG-5’
When RNA polymerase reaches a site called the __ region, it dissociates from the DNA at the end of transcription.
terminator
Pre-mRNA molecules contain intervening sequences that are not translated. The intervening sequences are also known as:
introns
In eukaryotes, transcription initially produces a longer RNA molecule called the __-__. This longer mRNA molecule is spliced, capped, and polyadenylated prior to translation.
pre mRNA
How are eukaryotic mRNAs modified before leaving the nucleus?
Introns are removed by splicing.
A cap is added to the 5’ end.
A poly(A) tail is added to the 3’ end.
During the elongation stage of transcription, nucleotides bind to the template strand and are covalently connected in which direction?
5’ to 3’
The sequence of a DNA template is 3’-GGTTCCTT-5’. What is the sequence of the RNA molecule that will be transcribed from this template strand?
5’-CCAAGGAA-3’
The sequences that are removed from mRNA and not translated are called
introns
In eukaryotic mRNA, sequences found in the mature mRNA are termed __.
exons
What happens during the process of mRNA splicing?
Exons are joined together.
Introns are removed from the transcript.
During transcription, ribonucleotides are added to the
3’ end of the mRNA transcript
Which end of a eukaryotic mRNA is processed by the addition of a modified guanine cap?
5’
Mature mRNAs of eukaryotes have a modified form of guanine covalently attached at the 5’ end. This event is known as
capping
What is the role of the 5’ cap on a eukaryotic mRNA molecule?
It allows the mRNA to bind to a ribosome for translation.
It facilitates the exit of mRNA from the nucleus.
At the molecular level, coding sequences that are translated are found in:
exons
How is the 3’ end of a eukaryotic mRNA modified?
A poly A tail is added to it.
How is the 5’ end of a eukaryotic mRNA modified
A cap is added to it.
What are the functions of the poly A tail on a mature eukaryotic mRNA?
It stabilizes the mRNA.
It aids in the export of mRNA from the nucleus.
Due to __, mature mRNAs of eukaryotes have a modified guanosine covalently attached at the 5’ end.
capping
The average human gene has about __ introns.
9
In eukaryotic mRNAs, the 5’ cap functions in all of the following EXCEPT
removal of introns from the mRNA
In eukaryotic mRNA, sequences found in the mature mRNA are termed
exons
A poly A tail is added to the ______ end of eukaryotic mRNAs.
3’
What is the name of the complex that removes introns from eukaryotic pre-mRNA molecules?
Spliceosome
A long poly A tail aids in the export of mRNAs from the:
nucleus
What is true of introns?
Introns are found in many eukaryotic genes.
A gene may have multiple introns.
What is the role of the 5’ cap on a eukaryotic mRNA molecule?
It facilitates the exit of mRNA from the nucleus.
It allows the mRNA to bind to a ribosome for translation.
