C2.1 Chemical signalling HL Flashcards
Ligand
A molecule that binds specifically to a receptor site of another molecule, initiating signal transduction in cells.
Stages of Signal Transduction
Involves ligand synthesis and release, transport and diffusion, receptor binding, signal transduction, cellular response, and signal termination.
Quorum Sensing
A process where bacteria communicate and coordinate behavior based on cell density, using signalling molecules like autoinducers.
Bioluminescence in Bacteria
A phenomenon where bacteria emit light, governed by gene expression in response to quorum sensing, like in Vibrio fischeri.
Ligand Binding
When a ligand specifically binds to a receptor, triggering a cascade of cellular responses, like gene expression modulation.
Autoinducers
Small signalling molecules used in quorum sensing, allowing bacteria to regulate behaviors like biofilm formation.
Positive Feedback in Cell Signalling
A mechanism where an output of a process enhances the response, amplifying the signal.
Negative Feedback in Cell Signalling
A process where the output of a system dampens the response, preventing over-amplification of the signal.
Role of Feedback Loops in Homeostasis
Feedback loops (positive and negative) are crucial for maintaining balance in cellular processes and overall homeostasis.
Biofilm Formation
A collective behavior of bacteria, influenced by quorum sensing, resulting in a protective layer formed by sticking together.
Quorum Quenching
Methods aimed at disrupting quorum sensing, useful in treating bacterial infections and preventing biofilm formation
Signal Transduction Cascade
Series of molecular events initiated by a ligand-receptor interaction, leading to a specific cellular response
Importance of Chemical Signalling
Essential for cell-to-cell communication, regulating processes like immune response, development, and homeostasis
Cell-to-Cell Interactions
Can be direct (through cell contact) or indirect (via secreted signalling molecules).
Role of Receptors in Signalling
Specific proteins that bind to signalling molecules, initiating cellular responses.
Importance of Signal Termination
Ensures that the signalling response is appropriate in duration and intensity, preventing excessive cellular responses.
Ligand Specificity
Receptors have specific binding sites that determine which ligands they can bind to
Cellular Responses to Signalling
Include changes in gene expression, enzyme activation/inhibition, and alterations in metabolic processes
Drug Resistance and Quorum Sensing
Understanding quorum sensing can help in developing strategies to combat drug-resistant bacteria
Applications of Quorum Quenching
Includes environmental contaminant degradation, medical treatments, and food industry applications
