RNA + transcription + translation Flashcards
3 types of RNA
mRNA, tRNA, rRNA
features of ribose nucleotide + RNA strands
ribose sugar,
- base uracil replaces thymine
make RNA more unstable - prevents over transcription
- Single stranded
can form stem + loops through intermolecular bonding of complimentary sequences
synthesis of mRNA
- by RNA polymerase 2 in the nucleoplasm
synthesis of tRNA
- by RNA polymerase 3 in the nucleoplasm
synthesis of rRNA
- by RNA polymerase 1 in the nucleolus
features of tRNA
- flattened = clover leaf like
- amino acid attachment site with ACC sequence
- anticodon loop (complimentary to mRNA codon)
tRNA + amino acid
- aminoacyl - tRNA
- amino acid binds to ACC sequence on attachment site
rRNA uses
component part of proteins
Process of Initiation of transcription
- TFIID unwinds DNA (replication bubble forms)
- promoter exposed
- TF2D binds to promotor through TBP
- Further Transcription Factors + DNA Pol 2 bind
- RNA polymerase 2 adds RNA nucleotides to produce a mRNA strand
3 parts of a promoter
1) regulatory protein binding region
2) Transcription factor binding region (TATA box)
3) RNA Polymerase binding region
features of a promoter
- found at - 25 base (25 before transcription),
gives space for polymerase - TATA sequence complimentary to TBP (TATA box binding protein)
- stay in place so many transcriptions can occur
3 transcription factors required to start transcription
1) promoter e.g. TATA box
2) initiator sequence (at transcription start site)
3) downstream promoter element (+30)
features of specific transcription factors
can bind directly to DNA
features enhancer
bind to DNA in vicinity of promotor to increase rate of transcription
example of general transcription factor
TF2D (TFIID)
