Transcription and Translation Flashcards
steps in between DNA and proteins?
RNA is the bridge between DNA and protein synthesis
1) Transcription
2) mRNA
3) Translation
Translation
the synthesis of a polypeptide chain using information in the mRNA
Ribosome
are the sites of translation
Transcription
is the synthesis of information in DNA (produces messenger- mRNA)
The central dogma
concept that cells are governed by a cellular chain of command
Codon
mRNA transcript of DNA tripplet
3 step process of transcription
1) Initiate (recognize where to start)
2) Elongate (make a copy)
3) Terminate (recognize where to stop)
Pre-mRNA processing
- 5 prime cap added and Poly-A tail added (like a label for when it leaves the nucleus, make sure its not destroyed or damaged)
- remove introns –> noncoding
- splice exons (coding) together
4 structures needed for translation
needed:
- mRNA: instructions from the nucleus
- tRNA transfer RNA carriers a single amino acid to the mRNA instructions
- Aminoacyl - tRNA: enzyme that loads the right amino acid to the growing polypeptide chain
- ribosome: protein + rRNA that facilitates tRNA adding amino acid to the growing polypeptide chain
tRNA
transfer RNA, carriers a single amino acid to match the mRNA instructions
Aminoacyl- tRNA synthase
enzyme loads the right amino acid in the tRNA
Ribosome
protein + rRNA that facilitates tRNAs adding amino acids to the growing polypeptide chain
3 binding sites in the ribosome
A site: holds tRNA that carriers the next amino acid to be added to the chain
P site: The P site holds the tRNA that carriers the growing polypeptide chain
E site: exit site, where discharged tRNAs leave the ribosome
Translation steps
1) turn mRNA into proteins
2) elongate (make amino acid chain)
3) recognize codons
4) attach the amino acid
5) scoot to the next codon
6) terminate (recognize where to stop)
Post translation modification
some proteins require additional modification in the endomembrane system
