Biology of food Essay Example | Topics and Well Written Essays - 1250 words - 1

Biology of food - Essay Example Genes are required to direct the production of functional molecules; also known as proteins. A process known as gene expression does this. Gene expression consists of two steps: transcription, and translation. Gene information is necessary in the production of proteins. Transcription is the first step done to get the information out of storage. The information stored in the DNA of a gene is relocated to an RNA (mRNA) molecule located in the cell nucleus; this process is called transcription. The DNA of a gene serves as a template for harmonizing base pairing. RNA polymerase II catalyzes the configuration of a pre- mRNA molecule; which is developed to form a mature mRNA. The mRNA transports the information from the DNA located in the nucleus into the cytoplasm. The second major step in gene expression, translation step follows in the cytoplasm. Three start factor proteins (IF1, IF2, and IF3) bind to the small subunit of the ribosome, resulting to a pre-initiation mRNA complex. The mRN A complex and methinine carrying tRNA, bind to the mRNA in close proximity to the AUG start codon; forming the initiation complex. The mRNA intermingles with the large ribosomal subunits, which releases the initiation factors. The large ribosomal subunit binds to the small ribosomal subunit to complete the initiation complex. ... Peptide bonds are formed via a peptidyl transferase activity. This procedure is repeated until the tRNA molecules have read all codons; amino acids joined to the tRNA have been connected in the growing polypeptide chain appropriately. With each mRNA, base sequence, codes for a specific amino acid. Each codon identifies a particular amino acid. Therefore, the mRNA sequence is used as a template to bring together the chain of amino acids that make up a protein. Transfer RNA joins the protein; by linking one amino acid within the interval. Protein production comes to a halt when the ribosome comes across a stop codon in mRNA. The stop codons are UAA, UAG, and UGA; Trna can recognize these codons. In place of the tRNA, release factors bind and facilitate the release of the mRNA from the ribosome and consequent dissociation of the ribosome. This sting of amino acids built by chromosomes finally acquires its activity during gene regulation, when gene expression is taking place. Signals fro m the location and or other cells activate transcription facets. The transcription features are proteins, which bind to the dogmatic locations of the gene. The rate of transcription can then be increased or decreased; establishing the amount of protein and product made. This is paramount as the string-of-stuff will resemble and act differently as per the specified activities. Environmental mutagens (like oxygen radicals) can result to DNA modifications causing mutations. These radicals react with DNA yielding lesions such as base modifications, cross-links, and strand breaks. A highly reactive hydroxyl radical, counters the DNA. This is done by the addition to double bonds of the DNA bases, as well as the blocking of the hydrogen atom from the methyl assemblage of thymine and C-H