1. yeast cells responding to mating signal: when exposed to mating factor they get protrusion and can mate 2.virus binding to cells induces a signal required for efficient penetration of the plasma membrane
what are the four types of cell communication?
1. endocrine: long distance using hormones 2. paracrine: short distance using local mediators 3. neuronal: quick and specific uses neurotransmitters 4. contact dependent: direct physical contact uses receptors
How might the same signal elicit a different response in different cells?
-the signal can bind to a surface receptor that has different intracellular signaling molecules, altering activity of different effector proteins, not just the receptor that is important, also have to receive and interpret the signal -variety of surface receptors on different cells, can use a relatively small number of signal molecules in different combinations to have subtle changes in cell behavior
What are the functional consequences of cell signaling?
survival, growth, differentiation, death
How does cortisol act?
-acts by activating a transcription regulator; a hormone produced by adrenal glands, diffuses across plasma membrane binds to receptor protein in cytosol -hormone receptor complex transported into nucleus through nuclear pores, cortisol binding activates receptor protein that binds regulatory sequences in DNA to activate or repress transcription
Draw the nitric oxide pathway
acetyl choline released by nerve, diffuses past smooth muscle and through basal lamina, reaches receptors on endothelial cells in blood vessel--cells make and release NO -NO diffuses out of endothelial cells into smooth muscle cells to make muscle cells relax