Quiz 9/4 Flashcards
Communication between cells is accomplished mainly by ___________ means
chemical
It is absolutely essential for multi-cellular organisms to survive and function properly
Cell to cell communication
Involves physical contact between cells or organisms
Direct
The 3 types of signaling that can occur between cells and organisms
direct, local, and long distance
What happens in local signaling?
Growth factors that are released into a localized area. (Usually for normal growth or repair)
Two examples of long distance signaling
Hormones and Pheromones
They are released in one part of the body to travel to another part of the body (an example of long distance signaling)
Hormones
Chemical mate attractants released into the environment
Pheromones
It is analogous to talking on the phone
Signal Transduction Pathway
______ _____________ won the Nobel Prize in 1971 for the discovery of the signal transduction pathway. He worked at Vanderbilt University.
Earl Sutherland
The 3 parts of the signal transduction pathway
reception, transduction, and response
First part of the signal transduction pathway
reception
Second part of the signal transduction pathway
transduction
Third part of the signal transduction pathway
response
What happens in the first step of the signal transduction pathway (reception)?
chemical binding to membrane protein
What happens in the second step of the signal transduction pathway (transduction)?
This is a series of steps in the changing of the signal to something the cell can understand at the nucleus or in the cytoplasm
What does transduction mean?
“to change or carry through”
What happens in the third step of the signal transduction pathway (response)?
This usually involves making something or turning on/off an enzymatic process. Usually involves DNA transcription and translation of enzymes.
The actual signal molecules
ligand
________ binds to the receptor protein (which are like hands) on the cell membrane or inside the cell.
Attachment causes conformational shape change in the receptor protein that sets in motion the transduction pathway
Ligand
Most common pathway used by the cell
G-Protein Pathway
3 Important Protein Pathways
G-Protein Pathway, Tyrosine-Kinase Pathway, Intracellular Receptors
__________ ___________ ___________-protein serves as attachment point for ligand; will change shape upon attachment of the “proper” ligand
G-Protein Linked Receptor
acts as a relay protein carrying message to the right location
G-Protein
Act like a catalyst for rapidly activating several relay proteins
Tyrosine-Kinase Pathway
Pathway is involved in growth/repair
Tyrosine-Kinase Pathway
Mostly for receiving hormones and steroids (lipids that don’t need receptor proteins on the cell membrane.)
Intracellular Receptors
Diffuse across the phospholipid bilayer
Intracellular receptors
usually starts the making of mRNA within the nucleus
Transcription factors
A ligand attaches to the receptor protein, it changes shape, GTP leaves a phosphate and becomes GDP, and then proteins connect to the phosphates to be activated
G-protein pathway
The ligand attaches to the receptor protein which is attached to the g-protein and a GDP. The protein changes shape and GTP replaces the GDP. Then the g-protein breaks off once it is activated. When the ligand detaches no more g-proteins can be activated.
G-Protein Pathway
A ligand attaches to the receptor protein then the shape changes. GTP leave a phosphate on the receptor protein and become GDP. This activates the protein. Relay proteins attach to the phosphates to be activated.
Tyrosine-Kinase Pathway
Aldosterone diffuses through cell membrane, binds with receptor, then moves into nucleus and binds to DNA. This creates mRNA. mRNA leaves the nucleus and binds to ribosomes in the cytoplasm which leads to the creation of certain proteins.
Intracellular receptors
