Transcription and Translation Notes PDF
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These notes provide a detailed overview of transcription and translation, two crucial processes in molecular biology. The document explains the central dogma of molecular biology and describes the structure of DNA, highlighting its role in protein synthesis. It also details the process of transcription, from initiation and elongation to termination, and the process of translation, such as initiation, elongation, and termination.
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Transcription and translation **MLO1.** Describe the central dogma of molecular biology. ** MLO2.** Explain how DNA is transcribed into mRNA, how mRNA is translated into protein and how proteins perform biological functions within cells. ** MLO8.** Explain, with the aid of diagrams,...
Transcription and translation **MLO1.** Describe the central dogma of molecular biology. ** MLO2.** Explain how DNA is transcribed into mRNA, how mRNA is translated into protein and how proteins perform biological functions within cells. ** MLO8.** Explain, with the aid of diagrams, the key organelles within a cell and how they function. ** MLO9.** Describe the basic structure of cell membranes and understand its importance in cellular compartmentalisation and maintaining osmolality. Explain the ways in which ions and large molecules are transported across cell membranes. ** MLO15.** Distinguish between key cell types found within the body and understand how cells form the building blocks of organs and tissues, and relate this to how the body functions as a whole. The **central dogma of molecular biology** is an explanation of the flow of genetic information within a biological system. It can be simplified as "DNA makes RNA, and RNA makes protein" but a more scientific explanation is that information cannot be transferred back from protein to either protein or nucleic acid. DNA structure: - Made of carbon, nitrogen, oxygen, phosphorus and hydrogen atoms - Made of many nucleotides containing a phosphorylated ribose sugar and a nitrogenous base of either adenine, thymine, cytosine or guanine Transcription process: - RNA polymerase binds to DNA at transcription start site - RNA polymerase moves along DNA (3' to 5') producing mRNA - RNA polymerase reaches stop sequence and mRNA is released - Activator proteins bind to enhancer sequences. Binding causes the DNA to bend, bringing them closer to a gene promoter sequence. Other transcription factor proteins join the activator proteins, forming a protein complex which binds to the gene promoter. This protein complex facilitates the attachment of RNA polymerase to the promoter region. - Before translation, splicing occurs, removing introns as they are non-coding Translation process: - Initiation at start codon AUG - tRNA with complimentary anti codon binds to start codon - Ribosomal LSU forms complex with SSU and tRNA in peptidyl site - tRNA molecule with corresponding anticodon enters aminoacyl site - Peptide bonds formed - Ribosome moves along mRNA molecule - When stop codon reached, release factor enters A site and releases polypeptide
