Cell Signaling Flashcards
How did cell signaling evolve?
Through exchange of mating factors
What is specificity?
One chemical, one shape, one receptor type, one response
What is the difference between local and long distance signaling?
- Local: signaling to self or adjacent cell
- Long distance: signaling multiple cells away
What is a ligand?
A molecule that binds to another (usually larger) molecule for communicating to a cell
What is a sending cell?
A cell which secretes ligands
What is a target cell?
A cell which intercepts a ligand with a receptor
What is a non-target cell?
A cell which doesn’t have a receptor for a given ligand
What are the two types of local signaling?
- Paracrine signaling
- Synaptic signaling
What is the ONE specific type of long-distance signaling?
Endocrine (hormonal) signaling
What is paracrine signaling?
In immune system: secreting cell discharges regulatory molecules (i.e., growth factor) into extracellular fluid
What is synaptic signaling?
In nervous system: nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell
What is endocrine (hormonal) signaling?
Specialized endocrine cells secrete hormones into body fluids, typically blood, targeting only specific cells (however, all over the body)
What type of ligand is most likely to cross a cell membrane?
A small, nonpolar molecule
What is signal transduction?
The process through which a ligand binds to an extracellular receptor, initiating intracellular change
What are the three steps of signal transduction?
Reception, transduction, response (outside, inside, activates)
What are the three roles of HORMONES in signal transduction?
- Travel long distances
- Bind to similar receptors on a wide variety of cell types
- Quick responsivity
What are the three types of signal transduction PATHWAYS?
- G Protein-Coupled Receptors
- Receptor Tyrosine Kinases
- Ion Channel Receptors
What are the key aspects of G Protein-Coupled Receptors?
- Phosphorylation
- Shape change
- 2* relay molecule
What are the key aspects of Receptor Tyrosine Kinases?
- Multiple phosphorylations
- Shape change
What are the key aspects of Ion Channel Receptors?
- Lock and key mechanism
- Chemiosmotic difference in charges
What is the function of protein kinase?
To transfer phosphates from one molecule to another
What is the function of protein phosphatase?
To remove PO4
What is the role of cyclic adenosine monophosphate (cAMP)?
Functions as a secondary relay molecule to amplify response in cell
What is the role of adenylate cyclase?
To convert ATP into Cyclic AMP
What is MHC?
Major histocompatibility complex
HOST CELL ID BADGES
What are toll-like receptors?
Pathogen associated molecular patterns
To ID pathogens
What is the role of antigen recognition in the immune system? + its three components.
PRESENTATION AND ID—
- Macrophages: ingest, digest, present
- T lymphocytes: memory and activation
- B lymphocytes: memory and antibodies
What is the role of histimine?
Inflammation (runny nose)
What is the role of prostaglandins?
Pain and fever
What is the role of immunoglobins?
Variable antibodies
What is the nervous system?
System of cells (neurons) which sense, interpret, and act on stimuli
All neurons…
- Inflow of information (become alert)
- Process information (think)
- Outflow information (respond)
What are the four basic neuron types?
Bipolar, unipolar, multipolar, pyramidal
What is the role of a synapse?
To serve as a messenger between the ends of two neurons
What is the role of a neurotransmitter?
If a synapse is the messenger, the neurotransmitters are the message.
In ion channels, what is the benefit of establishing action potentials?
Action potentials are brief pulses of electricity in a cell’s membrane–used by neurons to communicate with one another and send messages throughout the body
What does the graph of a neuron message look like?
Resting, stimulus, depolarization, action potential, repolarization, refractory period, resting state
