Cell signaling occurs through two main types: electrical signals using ions and chemical signals using signaling molecules. The majority (60-70%) of drugs bind to G protein-coupled receptors (GPCRs). Muscle contraction, writing, and boxing occur due to nicotinic acetylcholine receptor ion channels. Signaling molecules act by binding to receptors and are also called ligands. Signaling molecules can be agonists, which stimulate pathways, or antagonists, which inhibit pathways. End targets of cell signaling include transport proteins, cytoskeleton, enzymes, and genes. Signaling mediators include adapter proteins, effectors, cAMP as a second messenger, and protein kinases. Scaffold proteins cause localization of signaling mediators
33. Ans.) The two functions are:
a.) Acts as –ve feedback on
Hypothalamus to seize the
concentration of or release
of Gonadotropin and
34. b.) Enhances the condition of Endometrial lining for the possible
implantation of Fertilised egg:
i.) Promote proliferation of Endometrial Squamosa Epithelial cells
ii.) Increases Vascularisation
iii.) Increases thickness of walls
iv.) Promote formation of Endometrial glands &
v.) Increases Secretorial activity.
35. There are 3 types of termination mechanisms
for a pathway. They are:
A.) Making the
signaling molecule not
to be present in the
vicinity of receptor.
This is 2 types:
i.) Reuptake of
Signalling molecule
ii.) Degradation of
Signalling
molecule
B.) Making the receptor desensitize to the signaling
molecule. Ex: Phosphorylation of receptor
C.) Invagination of Signaling molecule-Receptor
complex(i.e internalization and degradation)
36. (These are the few important points for
Life Sciences competitive examinations).
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