Chapter 9; Textbook Flashcards
What is paracrine signaling?
Signaling between cells that are close together, uses diffusion through the extracellular matrix
What type of responses does paracrine signaling typically elicit?
Quick, short-lasting responses
How does paracrine signaling keep signals localized?
Paracrine ligand molecules are normally quickly degraded by enzymes or removed by neighboring cells
What’s an example of paracrine signaling?
Nerve cell synapses
What is endocrine signaling?
Signaling from distant cells via the bloodstream
What type of response does endocrine signaling elicit?
A slower, long-lasting response
What are the ligands released during endocrine signaling called?
Hormones
What are hormones?
Signaling molecules that are produced in one part of the body but affect other body regions some distance away
How do hormones travel?
Through the bloodstream
What’s a downside to the movement of hormones via the blood stream?
Hormones become more diluted
What is autocrine signaling?
When the target cell is the same (or similar) cell as the signaling cell
When is autocrine signaling used?
During the early development of an organism to ensure that cells develop into the correct tissues, to regulate pain sensation and inflammatory responses, and in apoptosis
What is direct signaling across gap junctions?
The small, fluid-filled channels (gap junctions) allow intracellular mediators to diffuse between the two cells
What do internal receptors do?
They respond to hydrophobic ligand molecules that are able to travel across the plasma membrane
What do cell-surface receptors do?
They span the entire plasma membrane and perform a signal transduction, through which an extracellular signal is converted into an intracellular signal
What do ion channel-linked receptors do?
They bind a ligand and open a channel through the membrane that allows specific ions to pass through
What do g-protein-linked receptors do?
They bind a ligand and activate a membrane protein (G-protein) that then interacts with either an ion channel or an enzyme in the membrane
How many transmembrane domains do g-protein-linked have?
7
What are enzyme-linked receptors?
Cell-surface receptors with intracellular domains that are associated with an enzyme
What can small hydrophobic ligands do?
Directly diffuse through the plasma membrane and interact with internal receptors
What makes water-soluble ligands unique?
They can’t pass through the plasma membrane unaided, so they bind to the extracellular domain of cell-surface receptors
What is phosphorylation?
One of the most common chemical modifications that occurs in signaling pathways, it adds a phosphate group to a molecule (like a protein)
What enzyme is used during phosphorylation?
Kinase
What is a second messenger?
It’s a small molecule that propagates a signal after it’s already been initiated, which helps spread a signal through the cytoplasm by altering the behavior of certain cellular proteins
What’s an example of a second messenger?
Cyclic AMP (cAMP)
What are inositol phospholipids?
Lipids that can also be converted into second messengers
What are growth factors?
The ligands that promote cell growth
What is quorum sensing?
Bacterial signaling, which detects the number of cells present in the environment
What does quorum sending use?
Autoinducers
What are autoinducers?
Found in quorum sensing, autoinducers are signaling molecules secreted by bacteria to communicate with other bacteria of the same kind
