AP Topic - Signal Transduction Flashcards
What are the two ways cells communicate with one another?
Cells communicate through direct contact, or with other cells from a distance via chemical signalling.
How do cells communicate with one another over short distances?
Using local regulators over short distances by using local regulators that target cells in the vicinity of the signal emmiting cell.
How do cells communicate over long distances?
Signals released by one cell can travel long distances to target cells of another type.
What is direct contact between cells known as?
Gap junction
What are short distance signals known as?
Paracrine signalling
What are short distance signals called?
Paracrine system
What are long distance signals called?
Endocrine system
What are gap junctions?
In animals and plasmodesmation (in plants) are tiny channels that directly connect neighboring cells
How do cells connect directly to one another?
Two cells may bind to another because the carry complementary proteins on their surface. When the proteins bind to one another, this interaction changes the shape of one or both proteins, transmitting a signal.
In what system are gap junctions unutilized?
Immune system
How does paracrine system?
Cells that are near one another communicate through the release of chemical messengers. (Ligands that can diffuse through the space between the cells)
When is paracrine system important?
During development, when they allow one group of cells to tell a neighboring group of cells what cellular identity to take on.
How does endocrine signalling work?
When cells need to transmit signals over long distances, they use the circulatory system where signals are produced by specialized cells and release into bloodstream
What do signal transduction pathways link?
Signal reception and cellular responses
What do many signal transduction pathways include?
Protein modification and phosphorylation cascades
What is phosporylation?
The addition of a Phosphate (ADP—> ATP)
What does signalling begin with?
Recognition of a chemical messenger (ligand) - by a receptor protein in a target cell
How does recognition of a ligand work?
The ligand binding domain of a receptor recognizes a specific chemical messenger
What can a ligand be?
A peptide, small chemical, or protein
What is an example of a receptor protein in Eukaryotes?
G protein-coupled
What is he purpose of signaling cascades?
Relay signals from receptors to target cells - amplyfiy incoming signals
What is the result of the amplification of signals?
The appropriate resoponse by the cell: ex: Growth, secretion of molecules, gene expression
What are ways a signal can be relayed?
- Ligand binds, intercellular domain of a receptor protein changes shape initiating transduction of signal
- Secondary messengers relay and amplify messages
- Binding of ligand to ligand-gated channels can cause the channel to open/close
What is signal transduction?
The process of a signal going from outside of the cell to inside
What are the three major steps of singal transduction?
- reception - Where a molecule binds to a receptor
- Transduction - A signal relay (cascade or amplfiying effect)
- Response - Cellular response
What is the relationship between receptors and ligands?
They often have closley matched pairs
What are the two types of receptors?
Surface cell receptors
Intercellular receptors
What are the three cell-surface receptors?
G Protein coupled receptors
Tyrosine Kinase
Ligand gated ion channels
What are intercellular receptors?
Recpetors in the cell - ligand must pass through membrane
What type of ligand would a intercellular ligand attach to?
A lipid soluble hotmone
What molecule to GPCRS use?
GTP
