BIO230H1 Lecture Notes - Lecture 19: Signal Transduction, Paracrine Signalling, Cyclic Adenosine Monophosphate
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BIO230H1 Full Course Notes
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Document Summary
Many bacteria release and respond to chemical signals. Signally coordinates motility, antibiotic production, spore formation, sexual conjugation in bacterial populations. Mating in budding yeast: signaling between yeast cells prepares them to mate. Aggregation of ameboid cells: signaling between dictyostelium cells draws them together to form a fruiting body. Cells can send out hundreds of different types of signalling molecules. E. g. , proteins, small peptides, amino acids, nucleotides, other small molecules, dissolved gases. These are exocytosed, emitted by diffusion or displayed on cell curface. Cells receive signals in 2 ways: cell-surface receptor. A hydrophilic signal molecule is recognized by a cell-surface receptor (transmembrane) protein of a target cell. A small hydrophobic signal molecule from a carrier protein is recognized by the intracellular receptor protein within the cytosol or nucleus of a target cell. Signalling can occur over short or long distances: Short: contact-dependent: signals are retained on the cell surface.
