2012年细胞生物学考试答2012年细胞生物学考试答案2012年细胞生物学考试答案2012年细胞生物学考试答案.doc

名词解释： 1：Signal patch：A pleated 褶皱structure existed in the tertiary structure of protein蛋白质三级结构. The sorting signal that leads protein into lysosome is signal patch. 2: Basic gene expressions (Constitutive gene expressions): It means the expression of house keeping gene. The expression of house keeping gene is not easy to be affected by the changes from inner or outer environment. 3: DNA replication licensing: Recent work has clarified how higher eukaryotic cells licence DNA replication precisely once per cycle. An inhibitor, geminin, prevents replication before mitosis by inhibiting the replication factor CDT1. Degradation of geminin in anaphase allows CDT1 to promote binding of MCM proteins, and hence DNA replication. Eukaryotic cells must replicate their entire DNA once, exactly once, and only once in each cell cycle. Over the past ten years the ground rules, as well as some of the proteins that regulate DNA replication, have been identified. Geminin protein is a key factor to block the replication by binding itself to CDT1 to block the binding of licensing factors to chromatin, inhibiting the onset of S phase. If geminin is removed from CDT1, the DNA duplication will initiated immediately. We call the course above as DNA replication licensing! 4:G0 phase of cell cycle: resting phase where the cell has left the cycle and has stopped dividing. 5:IPS: In 2006, investigators found that some somatic cells can be induced to return back to get “potency” as stem cells by the four genes, Oct-3/4, Sox2, c-Myc, and Klf4 transfected by RT virus. So, they called these stem cells as “inducible pluripotent stem cells” (iPS), and the protocol as “iPS technology”. These iPS cells can express some markers of ESC and be differentiated as any somatic cells. But, the iPS cells they obtained keep many differences with natural ESC at gene expression ways or epigenomics. 6: Gene：structural gene, house keeping gene and luxury gene: Gene means a DNA sequence encoding a protein