Protein Synthesis Flashcards
Transcription
Transcription is the first step in protein synthesis, where the genetic information stored in DNA is copied into messenger RNA (mRNA).
Transcription: Initiation
RNA polymerase binds to the promoter. The DNA strands then unwind, exposing the template strand that will be used to create the mRNA.
Transcription: Elongation
RNA polymerase moves along the DNA, reading the template strand in the 3’ to 5’ direction. As it moves, it synthesizes a complementary strand of mRNA in the 5’ to 3’ direction.
Transcription: Termination
Once the RNA polymerase reaches a certain sequence on the DNA, it stops transcribing and the RNA is released.
Translation
Translation is the second step in protein synthesis, where the mRNA produced during transcription is used to assemble a protein
Translation: Initiation (2 parts)
- The mRNA binds to the ribosome at the start codon (AUG)
- Then two subunits surround the mRNA strand
Translation: Elongation (3 parts)
- The rRNA begins reading the mRNA sequence in triplet sequences called codons.
- Each codon matches with a specific amino acid which will be brought to the rRNA by tRNA.
-Anti-codon sequence
Translation: Termination
A stop codon signals the end of the translation phase and the new protein is released.
RNA polymerase
RNA polymerase is the enzyme that reads the DNA code and creates the mRNA, which is essential for protein synthesis.
Double chained
(DNA or RNA)
DNA
Contains ribose sugar
(DNA or RNA)
RNA
Found in cytoplasm and nucleus
(DNA or RNA)
RNA
No different types
(DNA or RNA)
DNA
rRNA
Ribosomal RNA - rRNA is a component of ribosomes, which are the builders of the proteins.
mRNA
Messenger RNA - Carries the genetic information from the DNA to the ribosome, where it will be translated into a protein.
tRNA
Tranasfer RNA - tRNA is responsible for bringing the correct amino acids to the ribosome during translation.
Recessible operons
Recessible operons start on and need to be turned off
Inducible operons
Inducible operons begin off and turn on
What is an operon
An operon is a cluster of genes under the control of a single promote
Introns
Introns are removed by RNA
Exons
Exons go on to be covalently bonded to one another in order to create mature mRNA
