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20 Cards in this Set

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  • Back
What is a receptor protein?
A protein that binds to a specific signal molecule, inducing a change within the cell.
List the four types of cell signaling and describe them.
Direct contact- cell to cell
Paracrine- targets cells in immediate vacinity
Endocrine- targets distant cells through the blood
Synaptic- rapid communication between neurons and target cells
What is an intracellular receptor?
Receptors located within the cell that can trigger a variety of responses from the cell.
How do intracellular receptors act as gene regulators? What is an example of a signal molecule in this function?
They stimulate protein synthesis. Steroids.
How do intracellular receptors act as enzymes? What is an example of a signal molecule in this fuction?
They catalyze synthesis of intracellular signal molecules. NO(Nitric Oxide).
What are the three types of cell surface receptors?
Chemically gated ion channels, enzyme receptors, G-protein receptors.
What is a kinase?
An enzyme that activates proteins by adding a phosphate group.
How do enzyme receptor cell surface receptors usually activate intracellular proteins?
How do G-protein receptors work?
A receptor protein is activated, which activates a G-protein, which activates an enzyme or ion channel on the cell membrane.
Each G-protein receptor is a ___-pass transmembrane protein.
What are the first and second messengers?
The first messengers are external signals that are converted to intracellular signals, which are the second messengers.
What are two important intracellular signal molecules and where do they come from?
cAMP (synthesized from ATP by adenlyl cyclase), Calcium (extracellular fluid and/or endoplasmic reticulum)
What does calcium activate?
Calmodulin, which in turn activates many other proteins.
Why can a very small amount of signal molecule cause dramatic changes in the cell?
The signal is amplified.
What type of receptor is the photoreceptor in our eyes?
G-protein receptor.
How do cells tell the difference between cells similar to themselves and different cells?
They detect the tissue specific glycolipids on a cell membrane with their MHC proteins.
What are tight junctions? Where is one place where they are found?
Places where plasma membranes of cells connect in a sheet. Epithelial cells.
What are anchoring junctions? What role do desmosomes and cadherin play in this?
They are connections between two cells' cytoskeltons or extracellular matrix. Desmosomes connect the cytoskeletons and cadherin is the protein that makes the critical link.
What are communicating junctions? What are they in animals? In plants?
A junction that allows a chemical or electrical signal to pass between two cells. Gap junctions. Plasmodesmata.
Who made these flashcards?
Robert Fromm