Module 20 Terms - Cell Communication and Cell Cycle Flashcards
What are the general steps of cell signaling?
A signaling cell receives a stimulus
The cell releases signaling molecules
Those signaling molecules bind to receptor proteins on a target cell
The target cell responds
Signaling molecule
Chemicals released by cells that alter the activities of other cells (also called ligands)
Target cell
The cell that receives the signal
Ligands
Another name for signaling molecules
Quorum sensing
Communication among bacteria that leads to a response only when there are a high number of bacteria present in a given area
Hormone
A type of signaling molecule that travels in the circulatory system and affects distant cells
Endocrine signaling
Long-distance signaling, where hormones travel through the circulatory system. Used for communication across cells, tissues, and organs of multicellular organisms
Paracrine signaling
Between cells that are close to each other. Signaling molecules can move through diffusion between cells
Autocrine signaling
Where a cell communicates with itself
Contact-dependent signaling (juxtacrine)
Requires physical contact between 2 cells and happens in 2 ways:
- 1 transmembrane protein of one cell acts as the ligand and 1 transmembrane protein of the other cell acts as the receptor
- Other cells have passages/channels that connect them to other cells. There are no receptors in this form of cell communication
Plasmodesmata
Openings that cross through the membranes and cell walls of two plant cells
Sensor
A component of a system that detects when conditions have moved away from a particular level (set point)
Set point
A particular level for a condition
Effector
The component in the system that restores normal conditions following a disturbance in those conditions
Negative feedback
A stimulus acts on a sensor that signals an effector, which produces a response that opposes the initial stimulus and therefore turns off the signal
