Week 3 Chapter 14: Gene Expression Transcription
outline the stages of transcription
1. Initiation 2. Elongation / synthesis of the RNA transcript 3. Termination
how many modifications do eukaryotic mRNAs have?
3 1. Splicing 2. Capping 3. Poly A tail
What is a promoter?
A specific target sequence to which RNA polymerase binds.
state the central Dogma of molecular biology
DNA codes for RNA, which codes for proteins DNA →RNA →proteins
The terminator is a
DNA sequence that specifies the end of transcription.
Transcription factors are proteins that bind to
DNA sequences and control the rate of transcription.
The central dogma of genetics can be summed up by which of the following?
DNA → mRNA → polypeptide
Define gene expression with an overview of the process of transcription and translation as well as where they occur.
Gene expression refers to the use of the genetic information to synthesize a cellular protein. Process includes two steps: Transcription: information in the DNA is copied into RNA by transcription Translation: the RNA is then translated into a functional protein
outline the process of splicing out the introns to leave exons
Genes contain protein coding regions called exons, plus intervening, unusable sequences of nucleotides, called introns which are removed by a process called Splicing.
Transcription is the process of synthesizing
RNA from a DNA template.
The enzyme that synthesizes RNA from a DNA template is called
RNA polymerase
Which enzyme synthesizes RNA during transcription?
RNA polymerase
Elongation/ synthesis of the RNA transcript
RNA polymerase sides along the DNA in a open complex to synthesize RNA
how does genetic transcription factors and RNA polymerase assemble at the promoter?
RNA polymerase slides along the DNA, creating an open complex as it moves
what is the role of RNA polymerase in making a mRNA transcript?
Stored genetic information in genes has to be accessed and the enzyme RNA Polymerase is central to this process by first making an RNA transcript from DNA as part of the information transfer process. The RNA transcript is called mRNA.
how is transcription terminated?
The RNA polymerase transcribes a sequence of DNA known as a terminator.
describe the organization/ structure of a protein- encoding gene.
The promoter The coding sequence The terminator
how does genetic transcription factors and RNA polymerase form a complex to initiate transcription?
Transcription factors can bind to specific DNA sequences called enhancer and promoter sequences in order to recruit RNA polymerase to an appropriate transcription site. ... This complex initiates transcription, and the RNA polymerase begins mRNA synthesis by matching complementary bases to the original DNA strand.
coding sequence
a base-pair sequence that includes coding information for the polypeptide chain specified by the gene.
promoter
a base-pair sequence that specifies where transcription begins.
terminator
a sequence that specifies the end of the mRNA transcript.
termination
a terminator is reached that causes RNA polymerase an the RNA transcript to disassociate from the DNA
The flow of genetic information in a cell, from DNA to RNA to protein, is described as the ___ ___of genetics.
central dogma
A triplet of nucleotides that corresponds to an amino acid is known as a(n)
codon
The mRNA contains groups of three nucleotides that specify the amino acid sequence of a polypeptide. These three-nucleotide groups are called
codons
Coding sequences that are present in the mature mRNA are termed
exons
Sequences in DNA that are present in mature mRNA and which code for polypeptides are called
exons
True or false: Transcription occurs in two stages: initiation and termination.
false
At the molecular level, ______ is the process by which a gene's information is used to produce a polypeptide or functional RNA molecule.
gene expression
The overall process by which the information within a gene is used to produce a functional product is called
gene expression
The three stages of transcription are called ____, ____, and ____
initiation elongation termination
Noncoding sequences that are initially transcribed into mRNA are termed
introns
Sequences that are found between exons are called
introns
The transcriptional product of a protein-encoding gene is a(n) __ molecule.
mRNA
In prokaryotes, a protein-encoding gene is transcribed into an RNA molecule called ___ RNA.
messenger
A structural gene encodes a(n)
polypeptide
The DNA sequence that directs the exact location where transcription begins is called the
promoter
The sequence in DNA that signals RNA polymerase where to begin transcription is called the
promoter
In a gene, the DNA is transcribed into RNA from the end of the
promoter to the terminator.
The sequence of a gene's DNA that is transcribed starts from the ___ and extends to the ___
promoter; terminator
Structural genes are also known as ___ -encoding genes.
protein
The group of three nucleotides that signals the beginning of translation is called the
start codon
The end of protein synthesis is specified by a ___ ___, which is a triplet of nucleotides in the mRNA molecule.
stop codon
Initiation
the promoter functions as a recognition site for transcription factors. The transcription factor(s) enables RNA polymerase to bind to the promoter. Following binding, the DNA is denatured into a bubble known as the open complex.
The synthesis of an RNA molecule from a DNA template is called
transcription
Proteins that bind to DNA and control the rate of RNA synthesis are collectively called
transcription factors
The process of RNA splicing joins together
two exons