Chapter 9 Unit 3 Flashcards
Learn the material to do good on the test.
State the two things communication between cells require.
- Ligand 2. Receptor
What are the four basic mechanisms for cellular communication?
- Direct contact 2. Paracrine signaling 3. Endocrine signaling 4. Synaptic signaling.
Describe direct contact
It is where ligand molecules on the surface of one cell are recognized by receptor molecules on an adjacent cell.
Describe paracrine signaling
It is where ligands are released from a secretory cell bind to the receptors on adjacent cells.
Describe endocrine signaling
It is where special ligands called hormones are released from the secretory cells and bind to the receptors on or within cells throughout the body.
Describe synaptic signaling
It is where nerve cells release the signal ligands (neurotransmitters) which binds to receptors on nearby nerve or muscle cells.
What are signal transduction?
It is the series of chemical reactions that occur following the binding of a ligand to a receptor.
How does a cell respond when a ligand binds to a receptor?
Chemically
What is kinase?
It is an enzyme that adds a phosphate to a protein therefore activating or turning it on.
What is phosphatase?
It is an enzyme that removes a phosphate from a protein therefore deactivating or turning it off.
What are the three AA that are frequent in phosphorylation?
Serine, Threonine, and Tyrosine.
How many AA do you need for phosphorylation?
One of the three.
Where are cell surface or membrane receptors located?
They are on the plasma membrane.
Where is the intercellular receptor located?
It is located inside the cell.
List the three classes of membrane receptors?
- Channel linked or gated receptors 2. Enzymatic receptors 3. G protein- coupled receptors
What is an enzyme receptor called?
Receptor tyrosine kinase
`What two things happen when a signal ligand binds the membrane bound receptor?
It is dimerized and authphosphorylated.
What happens after the membrane bound receptor is dimerized and authphosphorylated?
The activated receptor then adds a phosphate to tyrosine on a response protein.
What is an example of a receptor tyrosine kinase?
An epidermal growth factor receptor which stimulates skin cells to replicate.
What is Kinase cascade?
It is a series of protein kinases that phosphorylate each other in succession amplifying the signal, therefore a few signal ligand molecules can cause a large cell response.
What is MAP kinases?
They stand for Mitogen-activated protein kinases.
Where are MAP kinases typically?
They are typically in plant products.
What is G-protein?
It is a protein bound to GTP.
What is G-protein-coupled receptor (GPCRs)
Receptors bound to G proteins.
G proteins is a what that can be turned on by a receptor?
A switch.
Signal ligand binds receptor, then G protein activates a(n) what?
An effector protein usually an enzyme.
Once activated what do effector proteins produce that then generates a cellular response?
A second messenger.
What is a common effector protein which converts ATP to cAMP which then acts as a second messenger?
Adenylyl cyclase
What are the other second messengers?
Inositol phosphates and calcium ions (Ca2+)
What does it mean if one of the second messengers increase?
It means that the cell has been activated.
What does Adenylyl cyclase at as after converting ATP to cMAP?
It serves as a second messenger to activate or inactivate proteins.
What can steroid hormones do?
They can go across the membrane
Where is calcium?
In the smooth ER.
Steroid hormones are nonpolar so they can cross the plasma membranes and go to what?
Steroid receptor.
What usually happens during the regulation of gene expression?
An inhibitor blocks the steroid receptor from binding to DNA until the hormone is present.
What are the three functional domains of a steroid receptor?
- Hormone-binding domain 2. DNA binding domain 3. Domain that interacts with coactivator to affect gene expression (activating or deactivating transcription)
What does the steroid receptor signaling do?
It regulates gene expression.
What are autoinducers?
They are small molecules produced by bacteria that regulates gene expression.
What is Ligand?
It is a signaling molecule from the cell.
What is a receptor?
It is a protein which the ligand binds to.
What do pores do regarding direct contact?
They can open and close.
Describe channel linked or gated receptors
The ion channel opens in response to ligand binding.
Describe enzymatic receptors
The receptor is an enzyme that is activated by ligand binding.
Describe G protein- coupled receptors
A G-protein ( protein bound to GTP) assist in transmitting signal.
What are MAP kinases activated by?
They are activated by kinase cascades.
Where is a receptor located?
It may be on the plasma membrane or within the cell.
What happens when the shape of the receptor changes?
The function changes, and they become active.
