BISC 101 Lecture 12: BISC 101 - midterm 2 review- Environment Interactions
30 Oct 2017
School
Department
Course
Professor
Document Summary
2. a hormone (cell-cell signal) released by receptor cell travels throughout body. 3. responder cells receive hormonal signal, transduce it external signal changes activity. Shoot bends away from hormone: what is the first plant hormone discovered, how do photoreceptors allow plants to detect presence direction, intensity & Phototropic response = occurs with blue light. Suggests hormone diffuses from tip down to shoot wavelength of light? auxin b/c mediated by light photoreceptors phototropin. Shows photoreversibility, switching b/w 2 diff conformations. Involved seed germination/ shade avoidance/ flowering: explain photoreversibility. Red light (660 nm) increased germination (drives photosynthesis) Auxin binds auxin receptors (tir1, abp1) signal transduction. 1. increased # proton pumps (h+-atpases) in plasma membrane. 2. lowers ph, activating expansion enzymes that unzip cell wall structure. 3. h+-atpases establish electrochemical gradient ion/solute uptake cell. 4. turgor pressure increases, expanding loosened cell wall. 2. gibberellins diffuse form embryo aleurone layer.
