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What is the purpose of cell communication in biological processes?
Cell communication is crucial for maintaining homeostasis and coordinating cellular activities.
What are the three mechanisms of cell communication?
Direct Contact, Local Signaling, Long-Distance Signaling.
How do cells communicate via Direct Contact?
Cells can communicate through gap junctions or plasmodesmata, allowing for the direct transfer of molecules.
What is Local Signaling?
A process where signaling molecules are released to affect nearby cells, such as neurotransmitters in synaptic signaling.
What is Long-Distance Signaling?
Hormones are released into the bloodstream, affecting target cells located far away in the body.
What are the main steps of a Signal Transduction Pathway?
Reception, Transduction, and Response.
What are G-protein-coupled receptors (GPCRs)?
Membrane proteins that detect molecules outside the cell and are involved in many physiological processes.
What happens during the activation of G-proteins?
The alpha subunit switches from GDP to GTP, leading to separation from the beta-gamma subunit and triggering signaling pathways.
What role do GPCRs play in the body?
They are involved in sensory perception, hormonal regulation, neurotransmission, and immune system function.
What is an Ion Channel Receptor?
A membrane receptor that opens to allow ions to flow in and out of the cell in response to specific signals.
How do Ion Channel Receptors function?
Ligands bind to extracellular domains, causing the receptor to change shape and open the ion channel.
What is a Receptor Tyrosine Kinase (RTK)?
Membrane receptors that play a critical role in signaling pathways related to growth, differentiation, and metabolism.
What triggers dimerization in Receptor Tyrosine Kinase (RTK)?
Ligand binding causes two RTK molecules to come together to form a dimer, activating the receptor.
What is a Phosphorylation Cascade?
A series of reactions where one enzyme activates another by adding a phosphate group, amplifying the signal.
What are the different types of cell signaling?
Autocrine, Paracrine, Endocrine, Juxtacrine, and Gap Junction signaling.
What is a second messenger?
Small intercellular molecules that relay signals from receptors to target molecules within the cell.
What is the role of cAMP in cell signaling?
cAMP activates protein kinases and plays a part in processes like glycogen breakdown and hormonal secretion.
What are the phases of the cell cycle?
Interphase (G1, S, G2 phases) and Mitotic Phase (M phase).
What happens during the S Phase of the cell cycle?
DNA is replicated, resulting in two sister chromatids for each chromosome.
What are the checkpoints in the cell cycle?
G1 checkpoint, G2 checkpoint, and M checkpoint, ensuring proper cell cycle progression.
What regulatory proteins fluctuate during the cell cycle?
Cyclins.
How do cancer cells affect the cell cycle?
They bypass normal checkpoints leading to uncontrolled cell division and tumor formation.
What is apoptosis?
Programmed cell death that is essential for development and maintenance in multicellular organisms.
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