Term
| WHAT IS CELL TO CELL COMMUNICATION? |
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Definition
| IT IS HOW CELLS TELL OTHERS WHAT TO DO |
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Term
WHICH ONE OF THE FOLLOWING STATMENTS IS FALSE?
A. CELL SIGNALING REUIRES A LIGAND BINDING TO A RECEPTOR.
B. MANY CELL SIGNALING RECEPTORS ARE FOUND IN THE PLASMA MEMBRANE OF THE CELL.
C. ONE LIGAND CAN TRIGGER MULTIPLE SIGNALING PATHWAYS.
D. LIGAND BINDING CAUSES THE TRANSMISSION OF A SIGNAL TO THE INTERIOR OF THE CELL.
E. NONE OF THE ABOVE SATEMENTS ARE FALSE. |
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Definition
E; NONE OF THE ABOVE STATEMENTS ARE FALSE; ALL ARE TRUE.
RECEPTOR=DOORBELL, LIGAND= PUSHING BUTTON |
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Term
| WHY MUST CELLS SIGNAL TO EACHOTHER? |
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Definition
BECAUSE CELLS MUST BE ABLE TO RESPOND TO EXTERNAL STIMULI.
ALLOWS FOR COORDINATION OF ACTIVITIES AND FOR CELLS TO CHANGE CHARACTERISITS IN REPONSE (EX. FIGHT OR FLIGHT; OR BRAIN TELLS BODY TO GO THROUGH PUBERTY). |
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Term
| WHAT ARE THE 3 SIGNAL TRANSDUCTION METHODS AND DESCRIBE A LITTLE BIT ABOUT THEM. |
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Definition
1. ELECTRICAL
-ONE NEURON IS CONNECTED DIRECTLY TO ANOTHER VIA GAP JUNCTIONS
2. SYNAPTIC
-NERUOTRANSMITTERS
3. CHEMICAL MESSENGERS
-HORMONES, GROWTH FACTORS.. EXC. |
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Term
| WHAT ARE THE 2 SIGNALING SYSTEM REQUIREMENTS FOR CELL TO CELL COMMUNICATION? |
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Definition
SIGNALING CELL (LIGAND) AND THE TARGET CELL
(RECEPTOR/TARGET WHERE SIGNAL MOLECULE BINDS)
-IF CELL HAS RIGHT RECEPTOR, IT WILL RESPOND. |
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Term
STATE THE DISTANCE FROM THE SIGNAL TO ITS TARGET:
ENDOCRINE SIGNALS..?
PARACRINE SIGNALS..?
AUTOCRINE SIGNALS.? |
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Definition
ENDOCRINE SIGNALS= TARGET IS FAR FROM SOURCE. EX BRAIN TO OVARIES
PARACRINE= TARGET AND SOURCE ARE NEARBY. EX INFLAMMINATORY RESPONSE/CELLS DIVIDE
AUTOCRINE=TARGET IS THE SOURCE. EX GROWTH FACTORS |
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Term
| WHAT ARE THE 3 CATEGORIES OF HORMONES? |
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Definition
1. SMALL LIPOPHILIC
2. HYDROPHILIC
3. LARGE LIPOHILIC |
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Term
| HOW DO SMALL LIPOPHILIC HORMONES WORK? |
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Definition
| HORMONE GETS IN, BINDS TO INTRACELLULAR RECEPTOR, THEN HORMONE-RECEPTOR COMPLEX BINDS TO TRANSCRIPTION CONROL REGION IN DNA WHICH TURNS ON GENE EXPRESSION (EX. STEROIDS) |
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Term
| HOW DO HYDROPHLIC HORMONES WORK? |
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Definition
SINCE THEY CAN'T GET ACROSS THE MEMRBANE, THEY HAVE RECEPTORS ON THE PLASMA MEMBRNAE THAT CREATE A 2ND MESSENGER (EITHER PEPTIDE HORMONES OR SMALL CHARED MOLECULES) IN ORDER TO GET THE MESSAGE ACROSS. HORMONE= FINGER, RECEPTOR= DOORBELL.
AN EXAMPLE OF THIS IS GROWTH HORMONE. |
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Term
WHAT ARE THE GENERAL STEPS FOR CELL TO CELL COMMUNICATION? PUT THEM IN CORRECT ORDER.
A. TRANSPORTED TO TARGET
B. ALTERS PROTEIN ACTIVITY OF ONE OR MORE ENZMES INSIDE CELL (USUALLY A KINASE)
C.PRODUCTION OF AN EFFECTOR MOLECULE
D. LIGAND IS MADE AND RELEASED
E.BINDS TO RECEPTOR ON TARGET
F.CAUSES CHANGE IN ACTIVITY INSIDE THE CELL
G.REMOVAL OF LIGAND FROM RECEPTOR (PRESS DOORBELL, THEN TAKE FINGER OFF).
H. RECEPTOR ALTERS SHAPE BECAUSE THE LIAGND IS BINDING. |
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Definition
| D. LIGAND IS MADE AND RELEASED-> A. TRANSPORTED TO TARGET-> E. BINDS TO RECEPTOR ON TARGET-> H. RECEPTOR ALTERS SHAPE BECAUSE THE LIAGND IS BINDING.-> C. PRODUCTION OF AN EFFECTOR MOLECULE-> B. ALTERS PROTEIN ACTIVITY OF ONE OR MORE ENZMES INSIDE CELL (USUALLY A KINASE)-> F. CAUSES CHANGE IN ACTIVITY INSIDE THE CELL -> G. REMOVAL OF LIGAND FROM RECEPTOR (PRESS DOORBELL, THEN TAKE FINGER OFF). |
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Term
| NAME 3 WAYS THAT RECEPTORS ARE CHARACTERIZED AS |
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Definition
-THEY ARE COMPLEMENTARY TO THE LIGAND (LIKE HAND IN A GLOVE)
-BIDING IS REVERSIBLE
-USUALLY A CONFORMATION CHANGE WHEN RECEPTOR AND LIGAND BIND
-RECEPTORS FOR SAME LIGAND CAN HAVE DIFFERENT EFFECTS ON DIFFERENT CELLS
-ONE CELL CAN HAVE DIF. RECEPTORS FOR SAME LIGAND ON THE SAME CELL (EACH KIND CAUSES DIF EFFECT INSIDE) |
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Term
| WHAT IS A LIGANDS FUNCTION? |
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Definition
| A LIGANDS ONLY FUNCTION IS TO BIND TO THE RECEPTOR IN WHICH IT IS NOT METABOLIZED (BROKEN DOWN). |
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Term
WHICH ONE OF THE FOLLOWING STATMENTS IS FALSE?
A. A LIGAND IS A MOLECULE THAT BINDS TO AND ACTIVATES RECEPTORS IN THE PLASMA MEMBRANE CAUSING THE TRANSMIISION OF THE SIGNAL TO THE INTERIOR OF TEH CELL.
B. A LIGAND IS A MOLECULE THAT BINDS TO RECEPTORS AND IS THEN TRANSPORTED INTO THE CYTOPLASM CAUSES THE TRANSMISSION OF THE SINGAL TO THE INTERIOR OF TEH CELL.
C. LIGAND BINDING IS REVERSIBLE.
D. USUALLY BINDING OF THE LIGAND TO ITS RECEPTOR CAUSES A CONFORMATINOAL CHANGE IN THE RECEPTOR. |
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Definition
B IS FALSE BECAUSE THE RECEPTOR DOESN'T LEAVE THE PLASMA MEMBRANE.
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Term
SOME HORMONES TARGET SITES THAT ARE DISTANT FROM THE SOURCE OF THE HORMONE. THIS TYPE OF SIGNALING IS CALLED_____ SIGNALING.
A. PARACRINE
B. ENDOCRINE.
C. AUTOCRINE.
D. SYNAPTIC |
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Definition
| B, ENDOCRINE, IS CORRECT BECASUE ENDCRINE= LONG DISTANCES, PARACRINE= SHORT DISTANCES, AUTOCRINE= TARGET IS THE SOURCE AND SYNAPTIC IS KIND OF SIGNALING PROCESS AND IS NOT PART OF THE GROUP. |
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Term
| WHAT ARE THE 4 MAJOR CATEGORIES OF SIGNAL TRANSDUCTION SYSTEMS? |
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Definition
| G-PROTEIN RECEPTORS, RECEPTORS WITH INTRINSIC ENZYME ACTIVITY, RECEPTORS LACKING INTRINSIC ENZYME ACTIVITY AND ION-CHANNEL RECEPTORS. |
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Term
| DESCRIBE THE G-PROTEIN SINGAL TRANSDUCTION SYSTEM. |
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Definition
-RECEPTOR BINDS TO LIGAND, CAUSES CONFORMATIONAL CHANGE IN THE RECEPTOR THAT ACTIVATES A G PROTEIN.
-CAN CAUSE PRODUCTION OF SECOND MESSENGER (EX. CAMP) |
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Term
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Definition
DIFFERENT THAN G PROTEIN RECEPTORS.
-IT SHUTTLES BETWEEN THE RECEPTOR AND EFFECTOR
IT BINDS TO GTP
-RELAYS CONFORMATIONAL CHANGE THAT RECEPTOR UNDERWENT WHEN IT BINDED TO THE LIGAND. |
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Term
| WHAT ARE THE 3 SUBUNITS OF THE G PROTIEN |
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Definition
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Term
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Definition
| It activates phospholipase C which is the enzyme that breaks down special membrane lipid. |
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Term
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Definition
| It inhibits adenylate cyclase. It turns off things. |
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Term
| What is cAMP and what does it do? |
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Definition
cAMP is a second messengery.
-it regulates cellular metabolism
it modifies a cAMP dependent protein kinase in cytosol (cAPKs)
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Term
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Definition
| They add phosphate groups to other proteins activating or inactivating them. |
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Term
| What is the structure of PKA (cAPK)? |
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Definition
| It is made of 4 subunits in which it has 2 regulator subunits and 2 catalytic subunits. The 2 regulator subunits each bind to 2 cAMP and also binds to C. |
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Term
| What happens when cAMP binds to PKA? |
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Definition
| It causes shape to change and makes R dissociate from C in which C becomes active. |
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Term
| How does the G protein signal transduction system that acivates adenylate cyclase work? |
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Definition
| Ligand binds to the receptor which results in a change in conformation which causes the G protein to associate with the receptor. The G alpha releases its GDP and binds a new molecule of GTP. |
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Term
| What is the termination of response? |
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Definition
It turns off the response of G proteins.
-Activity of the G protien only persists as long as the alpha subunit is bound to GTP and that the alpha and beta-gamma remain seperated.
(Once the alpha and beta-gamma come back together, it shuts down the signal transduction pathway). |
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Term
True or False:
G protein receptors consists of an alpha, beta, and gamma subunit. |
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Definition
| False; G protein can, but G protein receptors are different and do NOT have those subunits. |
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Term
True or false:
G protein when activated can activate adenylate cycalse causing an increase in cAMP leveles. |
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Definition
| True. Adenylate cycalse makes cAMP. |
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Term
True or false:
Adenylate cyclase activates a protein kinase. |
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Definition
| False. Adenylate cyclase makes cAMP, and cAMP activates a protein kinase. |
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Term
| How do beta blockers work compared to B1 adrenergic receptors on cardiac muscle? |
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Definition
| B1 adrenergic receptors promote an increase in heart rate by action of catecholamines (Fight or Flight) where beta blockers act as antagonists and slow down heart rate. |
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Term
| What is the difference between an antagonist and a agonist? |
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Definition
Antagonist= bind to receptor but DON'T activate it.
Agonist= bind to receptor and ACTIVATEs it. |
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Term
| How does having B2 receptors on the SMC in bronchi do? |
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Definition
| It results in the relaxation of SMC which opesn the airway. (reverses smptoms of asthma) |
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Term
| What is Cholera toxin and how does it work? |
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Definition
It causes life threatening diareha.
-the toxin changes the shape
-high levels of cAMP which changes certain mebrane proteins. |
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Term
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Definition
It provides engery for the flight or fight response by increasing blood glucose levels
-epinephrin binds to receptor which activates g protein system which increases cAMP in cytosol. |
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Term
Which of the following is not a step in the regulation of glycogen metabolism?
a. Epinephrine stimulates an increase in cAMP
b. A cAMP-dependent kinase phosphrylates glycogen phosphorylase
c. A cAMP-dependent kinase phosphorylates glycogen phosphorylase kinase
d. A rise in cAMP activates a cAMP-dependent protein kinase |
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Definition
| B is correct because it can't be C because it is kinase not just a phosphorylase. |
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Term
Which of the following events occurs when cAMP levels drop after removal of epinephrine stimulation?
a. Glycogen synthase is inactivated
b. Glycogen phosphorylase is activated
c. Glycogen phosphorylase kinase is activated
d. Phosphoryprotein phosphatase is activated |
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Definition
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Term
An agonist of the B1-adrenergic receptor would be expected to..
a. Open bronchioles in the small airways in the lung
b. Close bronchioles in the small airways in the lung
c. Increase heart rate and contractility
d. Decrease heart rate and contractility |
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Definition
| C is correct in which it increases heart rate and contractility. |
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Term
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Definition
| They are second messengers. |
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Term
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Definition
| It binds calcium, and has bind cites for it. When it binds, it changes the shape and then can bind to the target proteins and regulate the proteins effect/abilit to do things. |
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Term
_____ is an intracellular protein that binds calcium and activates enzymes.
a. Calmodulin
b. Protein kinase
c. DAG
d. IP3 |
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Definition
| It is A because calmodulin is a protein that margilated by calcium binding. |
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Term
Two products of phospholipase C activity that serve as second messengers are___ and ___.
a. Calcium and IP3
b. IP3 and protein kinase
c. IP3 and cAMP
d. IP3 and DAG |
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Definition
| D because PIP2 is broken down into IP3 and DAG |
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Term
Cylic AMP is produced by the enzyme____ and degraded by the enzyme___.
a. adenylate cyclase; calmodulin
b. calmodulin; adenylate cyclase
c. adenylate cyclase; phosphodieterase
d. phosphodiesterase; adenylate cyclase |
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Definition
| C is correct because denylate cyclase makes AMP |
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Term
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Definition
They are receptors with Intrinsic Enzyme Activity
-They invole the Ras family of singal tranducers
Ras= G protien that consits of one subunit (reg. cell growth) |
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Term
| What does the RTK receptor do? |
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Definition
It autophosphorylates things.
They link receptor to signal transduction pathway |
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Term
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Definition
| They are used for binding of ligands. |
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Term
| What does the transduction pathway receptor do? |
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Definition
| They send messages to cells to make things happen. |
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Term
| What are the typical domains of the RTK? |
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Definition
-Bind ligands
- Sginal transduction system
- Autophosphorylation (when RTK is activated)
-Polypeptide chain that span the membrane |
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Term
| What is teh end result of EGF activation of the EGF receptor? |
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Definition
Activating a mAPK
mAPK= adds phosphate groups (which end up chaing the effects of genes). |
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Term
| Explain how GAP1 and increased endocytosis would turn off the EGF signal transduction pathway described in this exercise? |
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Definition
GAP1= proteint aht enhances natural abilit of Ras to turn GTP into GDP; makes it happen faster.
Endcytosis= internalizes things outside of the cell. Takes the receptor from surface, which tops the signal. |
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Term
Would Ras activity increase or decrease for each of the following:
Deletion of the SOS gene |
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Definition
| The Ras activity would decrease because the SOS is how Ras becomes activated in which GDP is released, and GTP is activated. |
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Term
| What is the function of the psophorylated tyrosines? |
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Definition
| The phosphorylated tyrosines is the activation of signaling proteins found in the cytoplasm. They recruit proteins to the SH2 domain. |
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Term
| What is unique about GRB2 that allows it to bind to an acitvated EGF receptor? |
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Definition
| It has 1 SH2 domain and 2 SH3 domains. |
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Term
| Can GRB2 bind to an EGF receptor when ligand isn't present? |
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Definition
| No because GRB2 binds to the receptor to make pTry that it needs for it to bind. |
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Term
| Is it possible for EGF receptor to activate more than one signal-transduction pathway? |
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Definition
| Yes because more than 1SH3 bidning protein and SH2 domain (more than 1). Depends what is recruited which make different signals. |
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Term
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Definition
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Term
| How does the regulation of blood glucose work? |
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Definition
Insulin and Glucagon are secreted by islets of Langerhans
-insulin reduces blood glucose levels uses a RTK receptor on muscle and adipose.
-Glucagon increases blood glucose levels uses G protien receptor found primarily on liver cells. |
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Term
CQ. G-protein-linked receptors activate a heterotrimeric G protein through interactions between the receptor and the Gbg subunit. Upon binding to the receptor, Gbg subunit then catalyzes GDP/GTP exchange by the Ga subunit. How is this similar to the activation of Ras by a RTK?
a. Both require that the receptor becomes activated when GDP is replaced with GTP
b. Both the G protein and Ras are heterotrimeric proteins.
c. Both Ras and the G protein remove GDP and replace it with GTP to activate.
d. Both require the phosphorylation of a specific amino acid in the receptor for activation. |
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Definition
| C is correct both Ras and g protein remove GDP and replace it with GTP to activate. |
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Term
| What are some possible effects of having a defect in RTK for FGF? |
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Definition
| It is a dominate negative muation which the receptors are important in mesoderm development. For example, the tadpole in which most of the body does not develop. |
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Term
| What are dominant negative mutations? |
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Definition
| It is when one bad copy of a gene for receptor is in it making half of the receptor working and half of it not working correctly. Could also have 2 bad copies in which neither FGF receptors work properly which means that it can't recruit GRB2 to the membrane. |
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Term
| What are the 2 receptors lacking enzyme activity? |
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Definition
This type of signal transduction deals with immune response
-causes genes to get turned on (transcribbed, messages turn into proteins)
-ex.= Cytokine receptors (ex. infection)
-ex. Interfero (antivieral) |
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Term
STATs are normally found in the cytoplasm, but don’t move into the nucleus until they become activated. How do they become activated?
a. The JAK protein adds a phosphate group to the receptor activating a kinase that phosphorylates as SOS protien.
b. STAT monomers dimmerize when phosphate groups are added to the ligand.
c. The receptor adds a phosphate group to STAT monomers allowing them to dimerize.
d. JAK adds a phosphate group to STAT monomers allowing them to dimmerize. |
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Definition
| D is correct because it can not be A because JAK protien doesn't add the phosphate group to the receptor which adds phosphate group to STAT monomers. |
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Term
| What did the STAT dinners do once they get into the nucleus? |
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Definition
| A because they move into the nucleus, binds to STAT promoter and turn on specific genes. |
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Term
| What are ion channels and what do they do? |
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Definition
Flow of ions that communicate an event that is going happen inside the cell have receptor that associated with ion channel.
It is formed from glycoproteins; forms a 'tube' or pore.
-Either open or closed under certain circumstances (gated)
-Ions corss by concentration difference (hi to low)
-They are classified according to what opens and closes the gate. |
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Term
| How do you stop the reponse of cell to cell communication |
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Definition
IT is important because you need to be able to stop the response so you depolarize the membrane.
1. Reuptake by presynaptic terminals
2. Degrade the neurotransmitter into inactive molecules. |
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