BIOL 119 Lecture Notes - Lecture 1: Xylem, Thigmotropism, Membrane Potential
Document Summary
Chapter 40- plant sensory systems, signals, and responses. Plants receive and respond appropriately to a wide variety of environmental stimuli: light, gravity, pressure, prests/wounds. Living things gather information and respond to it. Stimuli may also include controversial stimuli such as smell (airbourne molecules) and. A potato left growing in darkness produces shoots that look white and unhealthy, and it lacks elongated roots. These are morphological adaptations for growing in darkness, collectively called etiolation. Signal transduction- pathways link an external signal to a response: after exposure to light, a potato undergoes changes called de-etiolation, in which shoots and roots grow normally. Reception: internal and external signals are detected by receptors- proteins that change in response to specific stimuli in de-etiolation, the receptor is a phytochrome capable of detecting light. Two types of second messengers play an important role in de-etiolation: ca2+ ions and cyclic gmp (cgmp)
