Glossary
Cell Communication
The intricate process by which cells send, receive, and respond to signals from each other and their external environment.
Example:
During embryonic development, cells engage in extensive cell communication to coordinate the formation of tissues and organs.
Cell Death (Apoptosis)
Programmed cell death, a controlled and orderly process that eliminates unwanted or damaged cells without causing inflammation.
Example:
During the development of human hands, the webbing between fingers is removed through apoptosis to create distinct digits.
Cell Differentiation
The process by which a less specialized cell becomes a more specialized cell type, acquiring distinct structures and functions.
Example:
An embryonic stem cell transforming into a neuron or a muscle cell is a prime example of cell differentiation.
Cellular Responses
The changes in cell function, behavior, or gene expression that occur as a direct result of a cell receiving and processing a signal.
Example:
Upon detecting a viral infection, an immune cell's cellular responses might include initiating programmed cell death or releasing antiviral proteins.
Environmental Factors
External conditions or stimuli, such as temperature, light, or chemical presence, that can influence cellular behavior and trigger responses.
Example:
A plant's leaves orienting towards sunlight is a direct response to environmental factors influencing its cellular processes.
Gene Expression
The process by which information encoded in DNA is used to synthesize a functional product, typically a protein, influencing a cell's characteristics.
Example:
When a cell needs to produce more digestive enzymes, it increases the gene expression of the specific genes coding for those enzymes.
Glucagon
A hormone produced by the pancreas that raises blood glucose levels by stimulating the liver to break down stored glycogen and release glucose into the bloodstream.
Example:
If you skip a meal, your pancreas releases glucagon to ensure your brain and other organs have a steady supply of glucose.
Insulin
A hormone produced by the pancreas that lowers blood glucose levels by promoting the uptake of glucose into body cells and its storage as glycogen in the liver.
Example:
After eating a carbohydrate-rich meal, your pancreas releases insulin to help your body manage the rise in blood sugar.
Ligand
A signaling molecule that binds specifically to a receptor, initiating a cellular response.
Example:
Neurotransmitters like serotonin act as ligands when they bind to specific receptors on nerve cells, transmitting signals in the brain.
Metabolism
The sum of all chemical processes that occur within a living organism to maintain life, including both the breakdown of substances for energy and the synthesis of new molecules.
Example:
When you exercise, your muscle cells increase their metabolism to rapidly produce ATP for muscle contraction.
Quorum Sensing
A type of cell communication in bacteria where they coordinate gene expression and behavior based on population density, using secreted signaling molecules.
Example:
Bacteria forming a protective biofilm often rely on quorum sensing to collectively initiate the production of the extracellular matrix.
Receptor
A protein, typically located on the cell surface or within the cytoplasm, that specifically binds to a signaling molecule (ligand) and initiates a cellular response.
Example:
The taste buds on your tongue contain specific receptors that bind to different molecules, allowing you to perceive sweet, sour, salty, bitter, and umami flavors.
Signal Transduction
The multi-step process where an extracellular signal is converted into a specific intracellular response, often involving a cascade of molecular events.
Example:
When adrenaline binds to a heart cell, a rapid signal transduction pathway leads to an increased heart rate.