Biology 1002B Study Guide - Quiz Guide: Adenine, Exocytosis, Ibuprofen
Cell Signalling
Steps to cell communication:
-Set up: Choosing signal/signalling molecule
1. Reception: Cell receives message from signalling molecule
-Depends on # and type of receptor presented on outer membrane
2. Transduction: Interpretation and relay of message
-Series of biochemical reactions to relay message.
3. Response: Cellular response activated
Communication Paths
-Direct/Indirect: Direct = Direct (Fastest), Indirect = Others
1. Direct cell signalling: Signal sent to cells in contact using gap junctions.
2. Autocrine and Paracrine: Messengers leaves the cell and travels short distance.
-Paracrine: Messenger travels to neighbouring cell.
-Autocrine: Messenger returns to original cell.
3. Exocrine: Messages released from glands.
4. Endocrine Signalling: Messenger travels through the bloodstream.
5. Neural Signalling: Short/Long distances in short time.
-Fastest of indirect pathway.
-Messengers arrive to neuronal cell→ Travels down cell via action potential→
Convert back to chemical to be released to next neuronal cell.
Signalling Messengers (Ligands)
-Change in cell/environment causes cell to send a message via chemical messengers
-6 Classes:
1. Steroids: Endocrine pathway.
-Derived from cholesterol ∴Lipophilic
-Cannot be stored in vesicles
-Either diffuses through membrane or bound to globular carrier protein (i.e.
albumin)
-Proteins must be globular, soluble and carry steroids into endocrine
pathway.
-Allows for messenger to arrive at its desired target
-Able to diffuse through membrane of target cells:
-Can reach intracellular receptors
-Can diffuse through nuclear membrane and act as gene transcription factors.
-3 Classes:
-Mineralocorticoids (i,e, Aldosterone): Regulates levels of minerals.
-Glucocorticoids (i.e. Cortisol): Regulates levels of sugar.
-Sex hormones (i.e. testosterone/estrogen)
2. Eicosanoids (Lipids): Paracrine and autocrine pathway (Too large for direct/gap
junctns)
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Document Summary
Cell signalling: reception: cell receives message from signalling molecule. Depends on # and type of receptor presented on outer membrane. Direct/indirect: direct = direct (fastest), indirect = others: direct cell signalling: signal sent to cells in contact using gap junctions, autocrine and paracrine: messengers leaves the cell and travels short distance. Convert back to chemical to be released to next neuronal cell. Change in cell/environment causes cell to send a message via chemical messengers. Messengers arrive to neuronal cell travels down cell via action potential . Either diffuses through membrane or bound to globular carrier protein (i. e. steroids: endocrine pathway. albumin) pathway. junctns) Proteins must be globular, soluble and carry steroids into endocrine. Allows for messenger to arrive at its desired target. Able to diffuse through membrane of target cells: Can diffuse through nuclear membrane and act as gene transcription factors. Eicosanoids (lipids): paracrine and autocrine pathway (too large for direct/gap.
