Cell communication Flashcards
What are the three stages of cell signaling?
Reception
Transduction
Cellular response
What is a signal transduction pathway?
information from cell surface to interior
Long distance molecules for cell signaling are _______, and longer distance molecules are _______.
Hormones
Pheromones
What is programmed cell death called?
Apoptosis
The binding between a signal molecule (______) and receptor is highly specific
ligand
A ________ change in a receptor is often the initial transduction of the signal
conformational
Most signal receptors are plasma membrane proteins, but some are not; they
are _______ receptors.
intracellular
Small or hydrophobic chemical messengers can readily cross the membrane and activate receptors. These include ______ hormones.
steroid
An activated hormone-receptor complex can act as a _______ ______, turning on specific genes
transcription factor
What are the three main types of membrane receptors?
G-protein-linked receptors
Receptor tyrosine kinases
Ion channel receptors
How does a G-protein linked receptor work?
A G-protein-linked receptor is a plasma membrane receptor that works with the help of a G protein
The G-protein acts as an on/off switch: If GDP is bound to the G protein, the G protein is inactive
How does a receptor tyrosine kinase work?
Receptor tyrosine kinases are membrane receptors that attach phosphates to tyrosines
A receptor tyrosine kinase can trigger multiple signal transduction pathways at once
How do ion channel receptors work?
An ion channel receptor acts as a gate when the receptor changes shape
When a signal molecule binds as a ligand to the receptor, the gate allows specific ions, such as Na+ or Ca2+, through a channel in the receptor
What are some benefits of enzyme cascades?
Multistep pathways can amplify a signal: A few molecules can produce a large cellular response (amplification)
Multistep pathways provide more opportunities for coordination and regulation (specificity)
What are second messengers?
Second messengers are small, nonprotein, water-soluble molecules or ions
The extracellular signal molecule that binds to the membrane is a pathway’s “first messenger”
Second messengers can readily spread throughout cells by diffusion (They are small.)
