Protein Synthesis
The production of proteins begins in the nucleus of a cell. Specific proteins are made based on a particular genetic sequence on a strand of DNA. This DNA sequence is then converted, or transcribed , to RNA. Each segment of RNA is then translated into specific amino acids, which are then linked by peptide bonds to form a protein.
Protein Synthesis is the formation of proteins by transcription and translation .
DNA – RNA – AMINO ACIDS – PROTEIN
Terminology
DNA: Gene: Sequence of nucleotides that code for a specific sequence of amino acids in a protein. Codon: Coded blocks of information corresponding to an AA sequence. DNA and RNA store genetic information as sets of 3 nucleotides. A Base Triplet is a series of three nucleotides of DNA that codes for a specific amino acid. Promoter Codon: Specific triplet code that identifies where transcription STARTS . Terminator Codon: Specific triplet code that identifies the END of transcription. RNA: mRNA (messenger RNA): are long strands of RNA that are transcribed from DNA and that travel to the ribosomes to direct precisely which amino acids are assembled. tRNA (transfer RNA): transports amino acids to the ribosome and position each amino acid to the correct place. rRNA (Ribosomal RNA): found in the ribosome and provides the site where polypeptides are assembled.
a) Transcription
Transcription is the first step of Protein synthesis and is the transfer of information from DNA to RNA, which occurs when an mRNA copy of the gene is produced.
Transcription Process:
Transcription is initiated when the enzyme RNA Polymerase binds to a particular sequence of nucleotides called a Promotor Codon located at the beginning of the gene. Starting there, the enzyme begins to partially unwind the DNA and move into the gene section. As it encounters each DNA nucleotide, it adds the corresponding complementary RNA nucleotide to a growing mRNA strand. GCTA in DNA would signal the addition of CGAU to the mRNA. The mRNA codes for a specific AA sequence.
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