Cell signaling Flashcards
Importance of cell signalling:
All cells and organisms must be able to respond to their changing environment.
Signal pathway:
- stimulus
- receptor
- transmission of signal
- effector
- response
Transduction is…
conversion of the original signal to a message that can be transmitted
Transmitting message involves…
crossing barriers such as cell surface membranes
Signalling molecules are usually very…
small for easy transport.
Signalling includes both…
electrical and chemical events and their interactions with each other.
The cell surface membrane is critical…
component of most signalling pathways because it is a barrier to the molecules.
In typical signalling pathway, molecules…
must cross or interact with the cell surface membrane
Signalling molecules are very…
diverse.
If the signalling molecule is hydrophobic such as…
steroid hormones it can diffuse directly across the cell surface membrane and bind to receptors.
Most of the signalling molecules are…
water soluble.
(Typical signalling pathway) Starts with signal arriving…
at a protein receptor in a cell membrane.
(Typical signalling pathway)The receptor has a specific…
a shape which recognises the signal. (only cells with this receptor can recognise it)
(Typical signalling pathway)The signal brings a change in…
the shape of the receptor, this spans the membrane and message is passed to the inside of the cell. (signal transduction)
(Typical signalling pathway)The change in shape of the receptor allows…
interaction with the next component.
(Typical signalling pathway)The next component is often…
G-protein, which releases a second messenger. Many of second messengers can be made, in response to one receptor.
The second messenger is…
a small molecule which diffuses through the cell relaying the message.
(Typical signalling pathway)Many produced second messengers represent…
amplification of the original signal.
(Typical signalling pathway)The second messengers usually activate…
enzymes, increasing the amplification at each sage.
(Typical signalling pathway)Finally, a required enzyme is…
produced which brings the required change in cell metabolism.
Signalling cascade is…
a sequence of events triggered by the G-protein.
(Other ways of alerting the activity of a cell by receptor)Opening an ion channel, resulting…
in a change of membrane potential
(Other ways of alerting the activity of a cell by receptor)Acting directly as…
a membrane-bound enzyme(e.g. insulin receptor)
(Other ways of alerting the activity of a cell by receptor)Acting as an intracellular receptor when…
the initial signal passes straight through the cell surface membrane.
Direct cell contact is…
another mechanism of signalling.
