5) Cell Communication Flashcards
What are the three steps of cell signaling?
- Reception
- Transduction
- Response
Explain the first stage of cell communication
- Reception
The signal (like a hormone or molecule) finds and attaches to a specific receptor on the target cell’s surface or inside the cell.
Think of it like a key fitting into a lock—only the right signal works for the right receptor.
Explain the second stage of cell communication
- Transduction
Once the receptor receives the signal, it starts a series of steps inside the cell to pass the message along.
This often involves proteins or molecules inside the cell (like a relay team) that amplify the signal or convert it into a form the cell can understand.
Explain the third stage of cell communication
- Response
The cell does what the signal is asking it to do!
This could be activating a gene, making a protein, releasing a chemical, or even changing how the cell behaves.
What are Signaling Cascades?
A signaling cascade is a chain reaction of molecular events triggered by a signal, such as a hormone, neurotransmitter, or growth factor, that binds to a receptor on or inside a cell. The cascade amplifies and spreads the signal within the cell, eventually leading to a specific cellular response.
Breaking it Down Simply:
Signal Starts the Process
A signaling molecule (ligand) binds to a receptor on the cell surface or inside the cell.
This activates the receptor, starting the cascade.
Relay Team of Molecules
The activated receptor sends the signal to a series of relay molecules (like proteins, enzymes, or ions).
Each step amplifies the signal—one molecule can activate many others, like a domino effect.
Second Messengers
Often, small molecules like cAMP or calcium ions (second messengers) help carry and amplify the signal.
Activation of Effector Molecules
The cascade ends with the activation of effector molecules, which carry out the cell’s response.
Cellular Response
The response could be anything from gene activation, protein production, cell division, secretion, or even cell death.
What are the two types of receptors?
- Cell Surface Receptors
- Intracellular Receptors
Cell Surface Receptors
These receptors sit on the cell membrane and help the cell detect signals (like hormones or neurotransmitters) from the outside world.
Types:
- G Protein-Coupled Receptors (GPCRs)
The most common type of receptor.
When a signal (like adrenaline) binds, the receptor activates a G-protein, which then triggers a series of reactions inside the cell.
Think of it like flipping a switch that starts a relay race. - Enzyme-Linked Receptors
These receptors have enzyme activity or work with enzymes.
When a signal binds, it activates the receptor’s enzyme function, often leading to chemical changes inside the cell. - Ligand-Gated Ion Channels
These are like gates for ions (charged particles) to pass through the cell membrane.
A signal (ligand) binds to the receptor, and the “gate” opens, letting ions (like calcium or sodium) flow into the cell.
Intracellular Receptors
These receptors are inside the cell, not on the surface. They are for signals that can pass through the cell membrane.
N/A
Explain these receptors
- ion channel
- G protein
- enzyme linked recptors ex: Ligand-Gated Ion Channel
- Opens/closes a channel for ion flow
- Activates a G-protein to start a cascade
- Activates enzyme activity to trigger signals
There are 4 types of cell signaling
- They differ in distance and length of reaction
endocrine, paracrine , contact dependent and autocrine
Explain autocrine signaling
cell targets itself
Explain direct signaling access gap junctions
cell targets cell by gap junctions
Explain paracrine signaling
cell targets nearby cell
Explain endocrine signaling
cell targets itself through the bloodstream
