BIOLOGY 172 Chapter Notes - Chapter 20.4, 28.4, 31.1: Vacuole, Xylem, Phloem
Document Summary
Rate of transcription of any gene in any type of cell is determined by the combination of transcription factors that are present in the cell and by the relative balance of activators and repressors. Combinatorial control is the regulation of gene transcription by means of multiple transcription factors acting together. All multicellular organisms at many developmental stages. Arabidopsis is a model organisms for developmental studies and presents a clear case of combinatorial control. Meristems are regions of undifferentiated cells, where growth can take place; similar to stem cells in animals growing points of shoots/roots/flowers. Floral meristems 4 whorls representing differentiated structures. 3 classes of mutants showing characteristic floral abnormalities. When a is absent, c is also expressed in whorl 1 and 2. When c is absent, a expends into w 3 and 4. A and c are mutually antagonistic: usually a silences c and prevents transcription in w1-2, usually c binds to microrna and prevents translation of gene a.
