Cell Signalling Flashcards
What is the final pathway in signaling?
A pathway that leads to multiple processes contributing to the final outcome, rather than a linear sequence of events.
This emphasizes the complex nature of signaling pathways in biological responses.
What are the effects of specific phosphorylation of proteins?
It can lead to:
* Enzyme activation (or inactivation)
* Nuclear (or cytoplasmic) localization of transcription factors
* Transcription factor activation (or inactivation)
* Actin polymerization (or depolymerization)
* Protein degradation (or stabilization)
* Activation of feedback inhibitory (or stimulatory) loops
Phosphorylation is a key regulatory mechanism in cellular signaling.
True or False: The traditional view of signaling is that receptor activation triggers a simple, linear sequence of biochemical intermediates.
False
The traditional view is oversimplified; signaling is more complex and involves multiple processes.
What is the role of Notch family receptors?
Ligand binding leads to proteolytic cleavage and nuclear translocation of intracellular Notch to form a transcription complex.
This mechanism is crucial for cell signaling in development.
What is the function of Wnt protein ligands?
They influence cell development through a pathway involving Frizzled family receptors and stabilization of β-catenin.
Wnt signaling is vital for various developmental processes.
Define paracrine signaling.
Signaling that affects only cells in the immediate vicinity through diffusion.
This type of signaling is characterized by rapid degradation of the signal.
What are intracellular receptors activated by?
Lipid-soluble ligands that can easily transit plasma membranes.
Examples include vitamin D and steroid hormones.
Fill in the blank: G-protein coupled receptors (GPCRs) typically activate _______.
GTP-binding regulatory proteins (G proteins)
GPCRs play a significant role in various signaling pathways.
What processes can ligand binding initiate in signal transduction?
- Open ion channels
- Activate G proteins
- Activate endogenous enzymes
- Trigger proteolytic events or change protein stability
These processes are key to initiating cellular responses.
What is apoptosis?
Programmed cell death involving activation of a proteolytic cascade and destruction of cellular components.
Apoptosis is crucial for regulating cell numbers and removing damaged cells.
What is necrosis?
A form of cell death resulting from injury or disease, characterized by cell membrane disruption and inflammation.
Unlike apoptosis, necrosis often leads to inflammation in the surrounding tissue.
What types of signals do cells respond to?
- Danger and pathogens
- Cell-cell contacts
- Cell-ECM contacts
- Secreted molecules
These signals dictate various cellular responses.
Define cell differentiation.
Changes in physical and functional properties of cells as they proliferate to form different body structures and organs.
Differentiation results from selective repression of different gene promoters.
What is the primary organizer in embryonic development?
Primordial chorda-mesoderm, which directs the development of adjacent tissues.
This organizer plays a crucial role in forming the body’s structures.
True or False: All cells have the necessary genetic information for the development of all structures required in the body.
True
However, differentiation involves selective gene expression.
What is the role of integrins?
Mediators of cell-ECM contacts.
Integrins are crucial for cell adhesion and signaling.
What do secreted molecules include?
Growth factors, cytokines, and hormones secreted by endocrine organs.
These molecules are essential for intercellular communication.
