who proposed. a model. to. show. the process. of. protein. synthetic. with. the. help of. bacterial cell
Answers
Explanation:
Protein biosynthesis (Protein synthesis) is a core biological process, occurring inside cells, which balances the loss of cellular proteins (via degradation or export) through the production of new proteins. Proteins perform a variety of critical functions as enzymes, structural proteins or hormones and therefore, are crucial biological components. As a result, protein synthesis is regulated at multiple steps [1]. Protein synthesis is very similar for prokaryotes and eukaryotes but there are distinct differences.
Protein synthesis can be divided broadly into two phases - transcription and translation. During transcription, a gene (section of DNA) is converted into a template molecule (messenger RNA) by enzymes, known as RNA polymerases, in the nucleus of the cell [2]. This mRNA is exported from the nucleus via nuclear pores to the cytoplasm of the cell for translation to occur. Subsequently during translation, the messenger RNA is read by ribosomes in the cytoplasm and the nucleotide sequence of the mRNA is used to determine the sequence of amino acids. The amino acids are joined together by peptide bonds (a type of covalent bond) to form a polypeptide chain.
Following translation of the mRNA into a polypeptide chain, this polypeptide chain must fold to form a functional protein i.e. fold to produce the functional active site of the enzyme. In addition, a folded protein may undergo different post-translational modifications, which can alter the proteins ability to function, where the protein is located within the cell (e.g. cytoplasm or nucleus) and the proteins ability to interact with other proteins [3] .
The incorrect folding of polypeptide chains can result in non-functional proteins, this is often caused by mutations in the underlying DNA nucleotide sequence. These mutations in the DNA change the subsequent mRNA sequence, which then changes the amino acid sequence in the polypeptide chain. These mutations can cause the mRNA sequence to be shorter due to earlier termination of transcription, thereby, producing a shorter polypeptide chain. Alternatively, the mutation can change the mRNA sequence altering the polypeptide chain by changing the amino acid sequence [4].
Biosynthesis of amino acids (the building blocks of proteins) is a complex process with many chemical reactions mediated by enzymes, which if mutated would shut down the pathway, resulting in no-growth. Beadle and Tatum proposed the "one gene one enzyme" theory. One gene codes for the production of one protein.