C2.1 Chemical signalling HL

Question 1

Ligand

Answer 1

A molecule that binds specifically to a receptor site of another molecule, initiating signal transduction in cells.

Question 2

Stages of Signal Transduction

Answer 2

Involves ligand synthesis and release, transport and diffusion, receptor binding, signal transduction, cellular response, and signal termination.

Question 3

Quorum Sensing

Answer 3

A process where bacteria communicate and coordinate behavior based on cell density, using signalling molecules like autoinducers.

Question 4

Bioluminescence in Bacteria

Answer 4

A phenomenon where bacteria emit light, governed by gene expression in response to quorum sensing, like in Vibrio fischeri.

Question 5

Ligand Binding

Answer 5

When a ligand specifically binds to a receptor, triggering a cascade of cellular responses, like gene expression modulation.

Question 6

Autoinducers

Answer 6

Small signalling molecules used in quorum sensing, allowing bacteria to regulate behaviors like biofilm formation.

Question 7

Positive Feedback in Cell Signalling

Answer 7

A mechanism where an output of a process enhances the response, amplifying the signal.

Question 8

Negative Feedback in Cell Signalling

Answer 8

A process where the output of a system dampens the response, preventing over-amplification of the signal.

Question 9

Role of Feedback Loops in Homeostasis

Answer 9

Feedback loops (positive and negative) are crucial for maintaining balance in cellular processes and overall homeostasis.

Question 10

Biofilm Formation

Answer 10

A collective behavior of bacteria, influenced by quorum sensing, resulting in a protective layer formed by sticking together.

Question 11

Quorum Quenching

Answer 11

Methods aimed at disrupting quorum sensing, useful in treating bacterial infections and preventing biofilm formation

Question 12

Signal Transduction Cascade

Answer 12

Series of molecular events initiated by a ligand-receptor interaction, leading to a specific cellular response

Question 13

Importance of Chemical Signalling

Answer 13

Essential for cell-to-cell communication, regulating processes like immune response, development, and homeostasis

Question 14

Cell-to-Cell Interactions

Answer 14

Can be direct (through cell contact) or indirect (via secreted signalling molecules).

Question 15

Role of Receptors in Signalling

Answer 15

Specific proteins that bind to signalling molecules, initiating cellular responses.

Question 16

Importance of Signal Termination

Answer 16

Ensures that the signalling response is appropriate in duration and intensity, preventing excessive cellular responses.

Question 17

Ligand Specificity

Answer 17

Receptors have specific binding sites that determine which ligands they can bind to

Question 18

Cellular Responses to Signalling

Answer 18

Include changes in gene expression, enzyme activation/inhibition, and alterations in metabolic processes

Question 19

Drug Resistance and Quorum Sensing

Answer 19

Understanding quorum sensing can help in developing strategies to combat drug-resistant bacteria

Question 20

Applications of Quorum Quenching

Answer 20

Includes environmental contaminant degradation, medical treatments, and food industry applications