Chemical Signals 1 BIOL 1407 Chemical Signals Cells

Chemical Signals 1 BIOL 1407

Chemical Signals • Cells use chemicals to communicate with other cells • http: //www. livevideo. com/video/9 DF 33 CE 7 B 1014 B 55 BEF 2322395 D 72133/neutrophil -chemotaxis. aspx • Photo Credit of Neutrophil engulfing anthrax bacteria: Tim Vickers, 2007, Wikimedia Commons

Chemical Signaling: Direct Contact

Chemical Signaling: Short-Distance

Chemical Signaling: Long. Distance

Chemical Signaling Between Individuals • Pheromones • Video of Orchid Wasp Mimic: http: //www. youtube. com/w atch? v=-h 8 I 3 cqpgn. A • Photo credit for Spined Soldier Bug eating Mexican Beetle larvae: USDA, 2006, Wikimedia Commons Article on Spined Soldier Bug and his pheromones: • http: //www. nytimes. com/1992/03/01/new s/cuttings-the-enemy-s-enemy-is-thesoldierbug. html? partner=rssnyt&emc=rss&pag ewanted=all

Signal Transduction Pathways

Receptors

Target Cells: Have Receptors for Signal

Target Cells and Specificity

Types of Hormones

Transport and Receptor Location

Water. Soluble Hormones

G Proteins

Second Messengers • c. AMP • c. GMP • IP 3 and DAG • Calcium • Calmodulin

Lipid. Soluble Hormones

Steroid Hormones • Brassinosteroids in plants • Steroid hormones in animals – Synthesized from Cholesterol – Testosterone, Progesterone, Estrogens – Cortisol and Aldosterone from adrenal cortex

Seed Dormancy and Germination • ABA – High levels inhibit germination = promotes dormancy • Gibberellins – High levels promote seed germination

Al-your-own skew-Tell-um

Trigger for Desert Seed Germination: Rain Photo Credit for Storm Over Western Ghats: Plane. Mad, 2006, Wikimedia Commons

Desert Seed Germination • Attenborough Video: – http: //www. you tube. com/watc h? v=z 1 IBn. HIO Fxs – Photo Credit for South Africa Desert in Bloom: Winfried Bruenicen, 2001, Wikimedia Commons

Volatile Chemicals • Jasmonic Acid and Plant Volatiles • Dodder plant seeks close relationship with tomato plant – http: //imagearchive. ps u. edu/displayimage. ph p? pos=-19895 • Photo Credit for Dodder in Bloom: Michael Becker, 2005, Wikimedia Commons

Photo Credit for Dodder on Acacia: Khalid Mahmood, 2007, Wikimedia Commons

Photo Credit for Parasitoid Wasp on Plant Bug Nymph: Scott Bauer, USDA, 2003, Wikimedia Commons

The End Unless otherwise specified, all images in this presentation came from: Campbell, et al. 2008. Biology, 8 th ed. Pearson Benjamin Cummings.