Tests back Chapter 11 No Distance Short Distance Long Distance 1. Messenger 2. Receptor 3. Transduction 4. Secondary Messengers 5. Cell Targets Signal Transduction Pathway Signal Disruption Pathways Disruptions Poison Diabetes • • • • • Cell division- reproduction of cells Cell cycle- life of cell Chromosomes- DNA in packed structures Chromatin- DNA and proteins Somatic cells- # of chromosomes per body cell (all except reproductive) • Gametes- reproductive cells (half of the somatic #) • Sister Chromatids- duplicated chromosome joined by centromere • Mitosis- division of genetic material • Cytokinesis- division of cytoplasm • Animals – cleavage furrow • Plants – Cell plate • Binary Fission- Division in half (prokaryotes) • Origin of Replication • Cell cycle is regulated by internal and external signals • Checkpoint- control point where stop and go signals occur • G1 •S • G2 • G0 • Protein kinases are enzymes that activate or inactivate proteins by phosphorylating them • To be activated the kinase must be attached to a cyclin • Because these kinases are dependent upon attachment of cyclin they are known as cyclin-dependent kinases or Cdks. • Cells respond to • “maturation-promoting factors” this is what triggers the cell’s passage past each checkpoint • Growth hormone • Density-dependent inhibition- Uncontrolled cell growth-