AP Biology Protein Synthesis | Winston-Salem Forsyth County Schools

University:
Winston-Salem Forsyth County Schools
Course:
AP Biology
Academic year:

2023
Views:

40

Pages:

2
Author:

Brandon Owen

Protein Synthesis ● Genetic information flows from a sequence of nucleotides in DNA to a sequence of bases in a mRNA molecule to a sequence of amino acids in a protein ● Cause of an amino acid substitution: A change occurred in the DNA sequence encoding that protein ○ Amino acid substitution can change the shape of the protein (changes the function) ● Transcription: RNA polymerases use a single template strand of DNA to direct the inclusion of bases in the newly formed RNA molecule. ● Messenger RNA Processing (produces Mature RNA) ○ Introns (the junk): They are cut from the DNA (Stay inside the nucleus) ○ Extrons join together & a poly-A tail & a GTP cap is added ○ mRNA molecules carry information from DNA to the ribosome ● Distinct tRNA molecules bind to specific amino acids & have anti-codon sequences that base pair with the mRNA ○ tRNA is recruited to the ribosome during translation to generate the primary peptide sequence based on the mRNA peptide sequence ● rRNA molecules are functional building blocks of ribosome ● Translation is initiated when the rRNA in the ribosome interacts with the mRNA at the start codon ○ The sequence of nucleotides on the mRNA is read in triplets called codons ■ Many amino acids are encoded by more than one codon ○ tRNA brings the correct amino acid to the correct location according to the mRNA ○ The process continues until a stop codon is reached ■ It terminates by the release of the newly synthesized protein ○ Translation of the mRNA to create a polypeptide/protein occurs on Ribosomes (present in the cytoplasm & rough ER) ● In prokaryotic organisms, translation of the mRNA molecules occurs while it is being transcribed ○ They don’t have a nuclear envelope that separates the genome from the ribosomes in the cytoplasm of the cell, unlike eukaryotes ● Nearly all living organisms use the same genetic code, which is the evidence for the common ancestry for all living organisms