BISC 101 Lecture Notes - Lecture 12: Signal Transduction, Phototropism, Cytoplasmic Streaming
16 Jun 2016
School
Department
Course
Professor
Document Summary
Plant sensory systems, signals and responses according to environment. Environmental stimulus sensory cell receptors hormone signal hormone receptor on target cells signal transduction (secondary messenger) cell f(x) (i. e. cell elongation) Transduction: process in which a biological cell converts one signal/stimuli to another. Positive = growth of plant tip towards light. Negative = growth of plant tip away from light. Hypothesised that hormones cause the bending: shoots bend away from side with the hormone. Cells on the dark side elongate faster than on the light side. Photoreceptors: detect the presence, direction, intensity and wavelength of light. 2 major classes of photoreceptors: blue light receptors. Phototropin involved in phototropic responses and the opening/closing of stomata is sensitive to the blue end of the light spectrum. Chryptochromes: are involved in timing of flowering: phytochrome photoreceptors. Shows photoreversibility; switching between two different comfirmations. Has ability to determine whether seed will germinate or not and avoid shade.
