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Biology 1002B Study Guide - Quiz Guide: Purine, Uracil, Pyrimidine

Course Code
BIOL 1002B
Tom Haffie
Study Guide

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Multiple Responses for Single Ligand (Ex: Norepinephrine)
-Message depends on the ligand and the receptor associated as well as the pathway
-Norepinephrine: Can bind to 3 diff. adrenergic receptors to stimulate different responses
-Binding to ɑ1:Activates PLC→ Triggers P)P pathway→ Activates Ca2+channels
-Increase [Ca2+] triggers diverse effects(depending on cell type)
-Binding to ɑ2: )nactivates Adenylate Cyclase→ Decreases [cAMP]→ )nactivates PKA
Closes Ca2+ channel
-Binding to β receptor: Activates Adenylate Cyclase→ )ncreases [cAMP]→ Activates
PKA→ Opens Ca2+ channel
Coordinating Responses
-Antagonism of cellular prevents futile cycle of opposite responses cancelling out
-Antagonistic pathways: Pathways that are linked and only one can be expressed at one
-Example: Insulin and Glucagon maintaining blood sugar levels
-)nsulin: Travels via endocrine pathway→ Binds to tyr-k receptors→ Signals cells to
express glucose transporters→Cell more permeable to glucose→Decrease [Glucose]
-Glucose returns to normal→ Less insulin release→ Glucose transporters
internalized via endocytosis
\-Glucagon: Starts same as insulin but causes cell to release glucose
-Pancreas can only release either insulin or glucagon. Not both.
Ending the Response
1. Ligand removed by distant tissue by diffusion due to low [ ] near receptor
2. Ligand degraded by extracellular enzymes
3. Ligand taken by adjacent cell:
-Ligand released→ Absorbed by adjacent cell via endocytosis
4. Ligand receptor complex internalized via endocytosis (Degraded by lysosome)
-Can also only degrade only the ligand and return the receptor to membrane
5. Receptor inactivated via dephosphorylation/phosphorylation
6. Part of signalling pathway inactivated
X-Ray Crystallography
-Compound isolated in form of crystals (Hard and time consuming)
-Crystals bombarded w x-ray
-Dispersion and inference patterns analyzed to determine 3D structure
DNA History:
-Friedrich Miescher (1868): Discovered DNA from pus cells and named it nuclein
.-DNA was not recognized as hereditary material until 1952
-D structure discovered in 95s by Watson and Crick With Rosalind Franklin’s data
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