34. Transcription - defintion and mechanism. Flashcards
Definition - process of transcribing/ making a copy of genetic information stored in a DNA strand into a complementary strand of RNA (mRNA) - with the help of RNA polymerases Transcription is the process of making an RNA copy of a single gene.
Definition - process of transcribing/ making a copy of genetic information stored in a DNA strand into a complementary strand of RNA (mRNA) - with the help of RNA polymerases Transcription is the process of making an RNA copy of a single gene.
Types of RNA:
mRNA - code for proteins
rRNA - catalyse protein synthesis
tRNA - adaptors between mRNA and amino acids
Types of RNA:
mRNA - code for proteins
rRNA - catalyse protein synthesis
tRNA - adaptors between mRNA and amino acids
Types of RNA:
SnRNAs - function in a variety of nuclear processes - e.g. splicing of mRNA SnoRNAs - function in a variety of cellular processes - e.g. transport of proteins into endoplasmic reticulum
Types of RNA:
SnRNAs - function in a variety of nuclear processes - e.g. splicing of mRNA SnoRNAs - function in a variety of cellular processes - e.g. transport of proteins into endoplasmic reticulum
A structural gene, is a gene that only codes for RNA
A structural gene, is a gene that only codes for RNA
Stages for transcription:
Initiation - begins with binding of RNA polymerase to the promoter in DNA. The first nucleotide complementary to DNA template, is coded.
Stages for transcription:
Initiation - begins with binding of RNA polymerase to the promoter in DNA. The first nucleotide complementary to DNA template, is coded.
Elongation - progressive adding nucleotides to the 3’ - end of the growing polynucleotide chain involving RNA polymerase (mRNA) a temporary DNA-RNA hybrid appears. The tension in DNA helix is removed by topoisomers
Elongation - progressive adding nucleotides to the 3’ - end of the growing polynucleotide chain involving RNA polymerase (mRNA) a temporary DNA-RNA hybrid appears. The tension in DNA helix is removed by topoisomers
Termination - RNA polymerase reaches palindrome - terminator. Protein factors cause it’s dissociation from DNA template. New mRNA strand is released for translation - to form protein
One or more sigma factors bind to RNA polymerase - allowing it to bind to promotor DNA. (include in initiation stage)
RNA polymerase separates 2 strands of DNA by breaking H bonds between the complementary DNA nucleotides, (include in initiation stage)
RNA sugar phosphate backbone forms.
H bonds of the RNA-DNA helix break - freeing the newly synthesised RNA strand. Enhancers - recognised by DNA binding proteins which increase the affinity of RNA polymerase to promotor.
Trans - regulatory factors - protein products of another DNA nucleotide sequence. e.g. transcription factors
Termination - continued - the DNA re-winds into its original configuration
Termination - RNA polymerase reaches palindrome - terminator. Protein factors cause it’s dissociation from DNA template. New mRNA strand is released for translation - to form protein
One or more sigma factors bind to RNA polymerase - allowing it to bind to promotor DNA. (include in initiation stage)
RNA polymerase separates 2 strands of DNA by breaking H bonds between the complementary DNA nucleotides, (include in initiation stage)
RNA sugar phosphate backbone forms.
H bonds of the RNA-DNA helix break - freeing the newly synthesised RNA strand. Enhancers - recognised by DNA binding proteins which increase the affinity of RNA polymerase to promotor.
Trans - regulatory factors - protein products of another DNA nucleotide sequence. e.g. transcription factors
Termination - continued - the DNA re-winds into its original configuration
In eukaryotes, the promoter regions are called elements: - TATA (Hogness) box - TATAAA
- CAAT box - GGT[AATCT
- GC boxes
In eukaryotes, the promoter regions are called elements: - TATA (Hogness) box - TATAAA
- CAAT box - GGT[AATCT
- GC boxes
