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