Chapter 9 Vocab: Cell Communication Flashcards
Define Cell signaling
The system of communication between cells through signaling pathways
Define Synapse
A site where a neuron makes a communicating connection with another neuron or an effector such as a muscle fiber or gland
Define Synaptic signaling (not found in the glossary)
- In the brain, a ligand-gate ion channel may remain active for less than 10 milliseconds.
- Occurs at chemical synapses between two neurons or between a neuron and a muscle cell
Define Electrical synapse
In the nervous system where plasma membranes of two connecting neurons are in direct contact and communication across such a synapse occurs by the direct flow of an electrical signal
Define Cell-Cell recognition
Communication by direct contact. Adjacent cells can communicate with each other when a membrane protein in one cell binds selectively to a membrane in the other cell.
Define Extracellular fluid
The fluid occupying the spaces between cells in multicellular animals
Define Chemical synapses
In the nervous system where the plasma membranes of the presynaptic and postsynaptic cells are separated by a narrow gap. Communication across such a synapse occurs by means of a neurotransmitter; that is an electrical impulse arriving at an axon terminal of the presynaptic cell triggers release of a neurotransmitter that crosses the gap and binds to a receptor on the postsynaptic cell, triggering an electrical impulse in that cell
Define Hormone
A signaling molecule secreted by a cell that can alter the activities of any cell with receptors for it; in animals, typically a molecule produced by one tissue and transported via the bloodstream to another specific tissue to alter its physiological activity
Define Reception
In signal transduction, the binding of a signal molecule with a specific receptor in a target cell. In neural signaling, the first of four components in which a stimulus is detected by specialized sensory neurons
Define Ligand
A molecule that binds to another molecule
Define Transduction
In cell signaling, the process of changing a signal into the form necessary to cause the cellular response. In prokaryotes, the process in which DNA is transferred from donor to recipient bacterial cells by an infecting bacteriophage
Define Signaling cascade
I do not know
Define Response
In signal transduction, the last stage in which the transduced signal causes the cell to change according to the signal and to the receptors on the cell. In neural signaling, the third and last component involving the action resulting from the integration of neural messages
Define Transmembrane protein
An integral membrane that extends entirely through the plasma membrane
Define Protein Kinases
Enzyme that transfers a phosphate group from ATP to one or more sites on particular proteins
Define Phosphorylation cascade
A series of phosphorylation reactions catalyzed by a series of protein kinases
Define Phosphorylation
The addition of a phosphate group to a molecule
Define Protein phosphatases
An enzyme that, with a nucleosidase, breaks down a nucleoside to a nitrogenous base, a five carbon sugar, and a phosphate. In general, a phosphatase removes a phosphate group from a molecule
Define Amplification
Occurs whenever a protein in a signaling pathway performs its function repeatedly, producing many copies of the next molecule in the pathway
Define Amplification
Occurs whenever a protein in a signaling pathway performs its function repeatedly, producing many copies of the next molecule in the pathway
Define Receptor tyrosine kinases (RTKs)
In signal transduction, a surface receptor with built-in protein kinase activity
Define G-protein-coupled receptors (GPCRs)
In signal transduction, a surface receptor to a signal by activating a G protein
Define First messenger
The extracellular signal molecule in signal transduction pathways controlled by G-protein- coupled receptors
Define Effector
In signal transduction, a plasma membrane associated enzyme, activated by a G protein, that generates one or more second messengers. In homeostatic feedback, the system that returns the condition to the set point if it has strayed away. In nervous systems, non neuronal cells that respond to neurotransmitters released from neurons
Define Second messengers
In particular signal transduction pathways, an internal, nonprotein signal molecule that directly or indirectly activates protein kinases, which elicit the cellular response
Define cyclic AMP (cAMP)
In particular signal transduction pathways, a second messenger that activates protein kinases, which elicit the cellular response by adding phosphate groups to specific target proteins. cAMP functions in one of two major G-protein coupled receptor response pathways
What is Inositol triphosphate (IP3)
A small, water soluble molecule that diffuses rapidly through the cytoplasm. Is a second messenger produced by breaking down a membrane phospholipid PIP2 with the enzyme phospholipase C
What does Diacylglycerol (DAG) do?
activate protein kinases, which phosphorylate target proteins and produce that cellular response
What is the primary effect of IP3 in animal cells
Activate ion channel proteins in the endoplasmic reticulum (ER), which release Ca2+ stored in the ER into the cytosol
What is the effect of IP3 in plants
IP33 releases Ca2+ primarily from the large central vacuole and is involved in reactions that close plant stomata in response to a hormone signal
Define Ligand-gated ion channels
A type of cell surface receptor that in response to a ligand binding, changes conformation, opening or closing an ion channel, thereby allowing or blocking ion movement through the channel
Define Steroid hormone receptors
Internal receptor that turns on specific genes when it is activated by binging a specific steroid hormone
Define Cross talk
Interaction by which cell signaling pathways communicate with one another to integrate their responses to cellular signals
