MCAT - DNA transcription and translation

RNA polymerase II

enzyme that makes RNA transcript complementary to the strand of RNA

DNA polymerase

uses a single strand of DNA as a template and synthesizes a strand of DNA complementary to the nucleotide in the template strand

splicing

remove the introns from the mRNA transcript by spliceosome to create mature mRNA

codons

triplets of nucleotides on mRNA that correspond to specific amino acids

nonsense codons or stop codons

UAA, UAG, and UGA

initiation or start codon

AUG

Anticodons

corresponding triplet nucleotide sequences found on transfer RNA (tRNA) molecules complementary to mRNA codons

Wobble Hypothesis

the first two nucleotides in a codon are critical for determining which amino acid is added to the growing protein chain. However, the third position is more flexible, allowing for non-standard base pairing

Initiation

Translation begins at the start codon, AUG

Small Ribosomal Subunit Binding

binds to the mRNA near the 5' end, scanning for the AUG start codon

tRNA Binding

initiator tRNA, carrying methionine, binds to the AUG codon via its anticodon UAC

Large Ribosomal Subunit Joining

forming the complete ribosome

Termination

Translation continues until the ribosome encounters a stop codon- UAA, UAG, or UGA- on the mRNA