C2.1 Cell signalling Flashcards
(31 cards)
What are ligands?
cell signalling molecules
To what do ligands bind?
to the protein receptors on the membranes of cells
What is quorum sensing?
type of cell signalling used by bacteria to detect density of the population, basically it allows bacteria to coordinate their action as a colony
What is the name for signalling molecules involved in quorum sensing?
autoinducers
What is vibrio fischeri?
A marine, Gram-negative bacterium known for producing bioluminescence
What triggers light production in Vibrio fischeri?
high population density that leads to high levels of AHL, which activates the lux operon
What type of feedback system is involved in Vibrio fischeri quorum sensing?
A positive feedback loop—more AHL → more gene activation → more AHL
What is AHL?
signalling molecule that vibrio fischeri use for quorum sensing
What’s the example of quorum sensing?
bioluminescence in Vibrio fischeri and mutualism with the bobtail squid
What are cytokines?
proteins that act as chemical messages within cells or between nearby cells (e.g. tissue cells)
Where calcium ions act an signalling chemical in animals?
in muscle fibres (binds to protein on actin to allow myosin head to attach) and neurons (causes the release of neurotransmitters)
What are the three main types of hormones?
- amines
- peptide
- steroids
What are the four types of neurotransmitters?
- amines
- amino acids
- esters
- gases
What are the characteristics and examples of amine hormones?
those are derived molecules from amino-acids, examples: adrenaline, melatonin
What are the characteristics and examples of peptide hormones?
those are small proteins or polypeptide chains, examples: insulin, oxytocin
What are the characteristics and examples of steroid hormones?
driven from cholesterol, examples: oestradiol, testosterone, cortisol
Which types of hormones bind to the surface of the target cells and which one binds inside the target cells?
amine and peptide hormones bind to the receptors on the surface and steroid hormones bind to the receptors inside the cell
How calcium ions are transported?
by calcium channels (passive), calcium pumps (active) or sodium-calcium exchanger
Where intracellular receptors can be found?
in the cytoplasm and in the nucleus
Why do transmembrane receptors have hydrophobic and hydrophilic regions?
to be embedded in the membrane and allow to detect the external signals from the signalling molecule and initiate action inside the cell
What is transduction pathway?
what happens after ligand binds to receptor
What is an intracellular pathway?
ligand enterns the cell, binds to receptor and regulates gene expression
What is a transmembrane pathway?
ligand binds with the receptor which changes its shape and it produces secondary messenger molecules causing reaction in the cell
What type of receptors are present for transmitters?
transmembrane receptors
