2.2 Flashcards
(22 cards)
What is the process of cellular communication
- Signal
- Reception
- Transduction
- Response
What are the four types of signalling?
Contact dependent
Auto crime signalling
Paracrine signalling
Endocrine signalling
What are ligands signals?
Extracellular chemical signal
Secreted by the signalling (secretory) cell
Bind to the target cell
Local and long distance messengers
What are hydrophobic ligands?
Cross the plasma membrane
Steroid hormones (estradiol, testosterone, vitamin D)
What are water soluble ligands?
Bind extracellular receptors
Small molecules (peptides and small proteins)
What are receptors
Specific proteins (reside of target cells)
Span the plasma membrane
Bind ligands (release by the signalling cells)
What is the lock and key model?
Receptor-ligands interactions are highly specific
A single ligands can bind to multiple receptors
Elicits different responses for different cell types.
What are receptor ion channels?
Cell surface receptor
On binding of ligands: change shape, channels opens, ions flow into the cell, alter intracellular composition and cell activity)
What are enzyme linked receptors?
Cell surface receptors
Enzyme linked
G protein (activation of enzymes, cascade of events involving activation of secondary proteins, amplification of signal)
Involved in the immune system response and inflammation
What are intracellular receptors?
Internal receptors
Bind lipid soluble ligands (ligands diffuse across the plasma membrane, binds a receptor in the cytoplasms or the nucleus)
The ligands-receptor complex, binds DNA and alters transcription and translation.
What are the four types of cellular signalling?
Direct communication, Autocrine signalling, paracrine signalling and endocrine signalling
What is direct communication between cells?
Gap junctions
What are feature of gap junctions?
Communication channels made of a porous protein, directly link the plasma membrane of neighbouring cells.
They facilitate passage of ions and small water soluble molecules.
What is autocrine signalling?
(Auto) self signalling, the signal cell is the target cell
What are features of autocrine signalling?
The released ligand binds to the receptor on the same cell
In embryonic development it guides differentiation.
Its involved in, pain regulation, inflammation and destruction of virus infected cells
What is paracrine signalling?
Short distance communication.
What are feature of paracrine signalling?
Secretory cells release ligands, ligands diffuse across the extracellular space, binds a receptor on a nearby target cell.
Quick response
Short lasting
What is endocrine signalling?
Long distance signalling
What are features of endocrine signalling?
Long distance signalling
Mesenger molecules like hormones released by endocrine glands, travel via the bloodstream and bind receptors on target cells .
Slow response
Long lasting effect.
What does the response to ligand-receptor interactions depend on?
The type of ligand, the type of receptor and intracellular signalling molecules.
What do extracellular receptors simulate?
Cell growth, differentiation, proliferation, movement/migration and death/survival.
What do intracellular receptors do?
Target and alter transcription and translation
