Chapter 11 Flashcards
What suggests signal molecules evolved in prokaryotes?
Signal transduction pathway similarities
What are the 2 forms of communication in local signaling?
- Direct contact and transfer between cell junctions
- Cell-to-cell recognition
Local regulator
Messenger molecule that travels short distances
What type of messenger is a growth factor?
Local regulator
What is the initial transduction of a signal?
Shape change of receptor
What are the three types of membrane receptors?
- G protein-coupled receptors
- Receptor tyrosine kinases
- Ion channel receptors
What is attached to the tyrosines in receptor tyrosine kinase pathways?
Phosphate group
What forms of messengers can cross membrane? As in, what are the physical characteristics of them?
Small or hydrophobic
A steroid is what kind of messenger?
Hydrophobic
An activated hormone-receptor complex acts as ______
transcription factor
What is the benefit of a multistep pathway?
Amplification of signal, coordination and regulation
Protein kinase
Proteins that phosphorylate proteins (transfer phosphate from ATP to protein)
Protein phosphatases
Proteins that dephosphorylate proteins (remove phosphates from proteins)
Second messenger
Small, nonprotein, water-soluble molecules that spread through cell by diffusion
In certain pathways, ______ _______ creates cAMP. How so?
- Adenylyl cyclase
- Converting ATP to cAMP
How is a G protein activated?
When its GDP is switched with a GTP
What does cAMP typically do after it is created?
Phosphorylates protein kinase A
In certain pathways, second messengers ______ and ______ lead to release of calcium into cell.
- IP3
- DAG
Why is there such a large concentration of calcium ions in the ER?
Calcium ions are actively imported from cytoplasm
Many pathways regulate synthesis of enzymes and various proteins, usually by…
Other pathways do what?
- turning genes on or off in the nucleus
- regulate activity of enzymes and proteins
At each step in a cascade, what is greater than in the previous step?
Number of activated products
Scaffolding proteins
Large relay proteins in which other relay proteins are attached
How can scaffolding proteins increase signal transduction efficiency?
Grouping different proteins in same pathway
What is the actual signal that is being transduced in the various pathways?
Interactions that involve shape changes
GTPase
Hydrolyzes GTP binding to G protein
