[04] Signal Transduction Flashcards
What is “signal transduction” in the context of human physiology?
The process by which a cell converts one kind of signal or stimulus into another.
What are the three stages of signal transduction?
- Reception
- Transduction
- Response
What happens during the “reception” stage of signal transduction?
A signal molecule binds to a specific receptor on the cell surface.
What happens during the “transduction” stage of signal transduction?
The binding of the signal molecule triggers a series of changes in a series of intracellular molecules.
What happens during the “response” stage of signal transduction?
The transduced signal triggers a specific cellular activity.
What are the types of molecules that often serve as signal molecules?
- Hormones
- Neurotransmitters
What is a “hormone” in the context of signal transduction?
A molecule, often a protein or steroid, that is produced by one part of the body and acts on target cells elsewhere in the body.
What is a “neurotransmitter” in the context of signal transduction?
A molecule that transmits signals across a chemical synapse, such as between two nerve cells.
What is a “receptor” in the context of signal transduction?
A protein molecule that receives and responds to a signal molecule.
What is an example of a receptor in signal transduction?
The G-protein coupled receptor (GPCR).
What is the function of a G-protein coupled receptor (GPCR)?
It activates an intracellular G-protein when it binds to a signal molecule.
What is a “G-protein” in the context of signal transduction?
A protein that binds the guanine nucleotides GDP and GTP and acts as a molecular switch.
What are “second messengers” in signal transduction?
Intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules.
Name two common second messengers in signal transduction.
- Cyclic AMP (cAMP)
- Inositol trisphosphate (IP3)
What is the function of “cyclic AMP (cAMP)” in signal transduction?
It amplifies the signal and activates specific protein kinases within the cell.
What is the function of “Inositol trisphosphate (IP3)” in signal transduction?
It triggers the release of calcium ions (Ca2+) from intracellular stores, modulating various cellular processes.
How does signal transduction affect human physiology?
It regulates numerous physiological processes such as immune responses, sense perception, cell growth, and apoptosis.
Define “apoptosis” in the context of human physiology.
The programmed cell death that occurs when a cell is damaged, unhealthy, or no longer needed.
What is the PKA pathway in the context of signal transduction?
The Protein Kinase A (PKA) pathway involves the activation of PKA by cAMP, leading to the phosphorylation of various proteins.
What is the primary signal molecule involved in the PKA pathway?
Cyclic AMP (cAMP)
What is the PKC pathway in the context of signal transduction?
The Protein Kinase C (PKC) pathway involves the activation of PKC, often via diacylglycerol (DAG) and calcium ions, leading to the phosphorylation of various proteins.
What are the primary signal molecules involved in the PKC pathway?
- Diacylglycerol (DAG)
- Calcium ions (Ca2+)
What is the TK pathway in the context of signal transduction?
The Tyrosine Kinase (TK) pathway involves the activation of receptor tyrosine kinases by signal molecules, triggering auto-phosphorylation and the subsequent activation of various intracellular pathways.
What is a receptor tyrosine kinase in the context of the TK pathway?
A type of cell surface receptor that can phosphorylate tyrosine residues on certain proteins when activated.
What is the IP3 pathway in the context of signal transduction?
The Inositol trisphosphate (IP3) pathway involves the production of IP3, which binds to IP3 receptors in the endoplasmic reticulum, triggering the release of Ca2+ and affecting various cellular processes.
What is the primary signal molecule involved in the IP3 pathway?
Inositol trisphosphate (IP3)
