Hydroxl group on the 2’ carbon of the ribose sugar.
The base uracil in place of thymine.
TYPES OF RNA.
There are three major types of RNA:
TYPES OF RNA.
Small nuclear RNA.
Small interfering RNA.
Other small RNAS.
Ribosomal RNA (rRNA)-is the most abundant form of RNA,
nucleotides are in a globular form,
combine with proteins to make ribosomes.
Ribosomes- are organelles where proteins are made
Transfer RNA (tRNA)- consist of a single chain of about 80 RNA.
nucleotides folded into a hairpin shape that binds to specific aminoacids.
Adopter molecule that carry specific amino acid to the ribosome.
Messenger RNA (mRNA)- consists of RNA nucleotides in the form of a single uncoiled chain.
carries genetic information from the DNA
in the nucleus to the cytosol of a eukaryotic cell.
DNA is transcribed into RNA by DNA-dependent RNA polymerase (usually just called RNA polymerase ).
After binding to its start site in DNA, a specific sequence of base called the promoter, RNA polymerase & its supporting accessory proteins synthesize RNA using the base sequence of one strand of double helix DNA.
a promoter sequence on a DNA template.
RNA polymerase and accessory transcription factors.
A region on the DNA that determines the specificity of transcription of a particular gene.
Promoters contain specific DNA sequences and response elements which provide a binding site for RNA polymerase and for proteins called transcription factors that recruit RNA polymerase.
is a complex multisubunit enzyme, responsible for the transcription .
interacts with the promoter regions of genes as well as with a variety of elements and transcription factors to determine essentially all of the parameters that govern transcription.
Classess of RNA polymerase.
RNA polymeraze 1 : synthesizes the precursor of rRNA named pre rRNA .
RNA polymerase 2: synthesizes pre mRNA.
RNA POLYMERASE 3: synthesizes pre Trna.
All these enzymes synthesize what is called primary transcript or immature RNAs (pre form) which by some modifications occur after transcription, will give the mature rRNA, mRNA and tRNA.