Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
What is cell signaling?
|
mechanisms by which cells communicate with one another
|
|
|
Define: signaling molecules
|
hormones and other molecules that initiate cell response
|
|
|
Define: target cells
|
have receptor proteins to which the signaling molecules binds
|
|
|
Describe receptors
|
1. function to act as transducers
2. may not show absolute discrimination in binding 3. a signal from hormone binds to hormone receptor, which will initiate a response to the cell |
|
|
What happens if the target cells are not in close proximity?
|
the signal must be transported to them, usually by blood
|
|
|
What does cellular response depend on?
|
1. hormone concentration
2. receptor number 3. receptor affinity 4. agonist vs antagonist |
|
|
Describe agonist v antagonist in hormone
|
hormones can act in pairs; agonists work together to increase an overall response, while antagonist work to decrease a response
ex: glucagon and insulin |
|
|
Chemical messengers - ways for hormone transport
|
1. blood (for long distance - most hormones travel this way_
2. released through interstitial fluid (paracrine and autocrine) 3. intercellular 4. contact dependent 5. neurotransmitters |
|
|
what are paracrine signals?
|
affect other cells in the area; localized interactions (ex: histamine)
|
|
|
What are autocrine signals?
|
1. affect the molecules that release them (auto)
|
|
|
what is intercellular signalling?
|
gap junctions
|
|
|
what is contact depending signaling/
|
receptors
|
|
|
What is neurotransmitters?
|
signaling/target nuerons - cell to cell communication
|
|
|
Major stages in cell signaling
|
1. signal release
2. signal binding 3. transduction 4. response |
|
|
What is cell transduction?
|
converting extracellular signal into intracellular response
|
|
|
Where are peptide hormones located?
|
surface of cell
|
|
|
What is cAMP?
|
secondary messenger
|
|
|
Describe the G protein-cAMP signaling process
|
1. signaling molecule binds with Gprotein-linked receptor in membrane (GDP)
2. signal molecule-receptor complex activates G protein 3. GDP is split and becomes GTP 4. G protein (GTP) activates adenylyl cyclase which catalyzes synthesis of cAMP from ATP 5. cAMP activates protein kinase which phosphorylates proteins 6. cellular response |
|
|
Epinephrine activation of liver cell
|
G-protein - cAMP signaling process but the signal that activates the g-protein is epinephrine
|
|
|
Describe G protein-PHospholipase C signaling process
PAGE 142 |
1. signaling molecule binds with g-protein-linked receptor & activates g-protein
2. signal mol-receptor complex activates phospholipase C which splits PIP2 into DAG and IP3 3. DAG is secondary messenger and activates protein kinase enzymes that phosphorylate protein 4. some cellular activity altered 6. IP3 binds to Ca channels in ER 7. Ca released act as secondary messengers and alter some cell activity` |
|
|
What are secondary messengers in g-protein-phospholipase signaling?
PAGE 144 |
1. signal
2. DAG 3. calcium |
|
|
What are secondary messengers in g-protein-cAMP signaling?
|
1. signal
2. cAMP |
|
|
Describe scaffolding proteins
FIGURE 6-13 |
1. organize groups of intracellular signaling molecules into signaling complexes
2. position enzymes close to their substrates and prevent enzymes from being co-opted into other pathways |
|
|
Describe signal amplification
|
1. signal transduction cascade
2. magnifying the strength of a signal 3. ex: epinephrine 4. occurs at several steps along the cascade |
|
|
Describe steroid hormones
|
1. testosterone ring structure
2. direct effect on transcription 3. targets cytoplasmic/nucleus receptors 4. transported straight to nucleus |
