MolecularBiology分子生物学-m.pptVIP

* * * * * * * * * * * grid cells (blue) place cells (yellow) * In what has become known as nanoscopy, scientists visualize the pathways of individual molecules inside living cells. They can see how molecules create synapses between nerve cells in the brain; they can track proteins involved in Parkinsons, Alzheimers and Huntingtons diseases as they aggregate; they follow individual proteins in fertilized eggs as these divide into embryos. timulated emission depletion (STED) microscopy, developed by Stefan Hell in 2000. Two laser beams are utilized; one stimulates fluorescent molecules to glow, another cancels out all fluorescence except for that in a nanometre-sized volume. Scanning over the sample, nanometre for nanometre, yields an image with a resolution better than Abbes stipulated limit. single-molecule microscopy. The method relies upon the possibility to turn the fluorescence of individual molecules on and off. Scientists image the same area multiple times, letting just a few interspersed molecules glow each time. Superimposing these images yields a dense super-image resolved at the nanolevel. 二、基本知识介绍 人类基因与基因组 人类基因典型结构 中心法则 The Central Dogma 人细胞中的基因表达 FACT 1: an uniform genome in almost every cell of human body FACT 3: the shape and function of each type of cell are different FACT 2: the proteome in each type of cell is different Some Facts in Human Cells the types and amounts of the various proteins in a cell the concentration of mRNA and the frequency at which the mRNA is translated which genes are transcribed and their rate of transcription in a particular cell type TRUTH: the gene is differentially expressed regulation same genome in all cells of an organism regulation regulation Gene differential expression Gene Expression Occurs by a Two-Stage Process Transcription: generates a single-stranded RNA identical in sequence with one of the strands of the duplex DNA Three principal classes of products: message RNA (mRNA) transfer RNA (tR