Basic Principles of Biological Communication Flashcards
How can a signalling cell send signals to a target cell?
Via signalling molecules/ ligands/ transmitters
What are receptors?
Transmembrane proteins
What are the 3 methods of local communication?
- Contact dependent
- Paracrine
- Autocrine (signalling molecule bound to target cell)
What are the 2 methods of distant communication?
Endocrine
Synaptic
What is the function of dendrites in the neurone?
Dendrites receive inputs and synapse with other cells.
What is the alternative name for the cell body of a neurone?
The soma
What ensures action potentials can only flow from soma to synapse?
The polarity of the neurone cell
How does endocrine communication work?
- Hormones are released from specialised cell populations forming endocrine glands
- Hormones travel through the bloodstream and bind to receptors.
What determines the duration of the hormone signal?
The half-life of the signalling molecule.
Where are intracellular receptors located?
In the cytoplasm or in the nucleus.
Ligands that bind to intracellular receptors must be hydrophobic. Why is this?
As they must pass through the phospholipid bilayer.
What are the 3 regions of a membrane receptor?
- An extra-cellular domain
- Transmembrane domain
- Intracellular domain
What is found in the extracellular domain?
- The hormone binding site
- The N-terminus
What is found in the intracellular domain?
The C - terminus
What are ligand-gated ion channels?
Protein channels which allow certain ions to pass through when ligands are bound (and change the structure).
What are enzyme-linked receptors?
- Cell surface receptors with intracellular domains associated with an enzyme.
What do receptor tyrosine kinases do?
They transfer phosphate groups to the amino acid tyrosine.
What are the 3 subunits of G protein coupled receptors?
Alpha
Beta
Gamma
What happens when a ligand binds to the G protein receptor site?
It activates the alpha sub-unit and causes dissociation of beta-gamma units.
What do these sub-units then activate?
They stimulate/ inhibit enzymes in the cell membrane causing the opening or closing of ion channels.
What sub-unit is used to define the G protein?
The alpha sub-unit.
Which is faster, endocrine or neuronal communication?
Neuronal communication is faster.
Which is more energetically efficient, endocrine or neuronal communication?
Endocrine communication is cheaper energetically.
