Topic 3.4: Chemical Signalling (HL) Questions

A cell releases a signalling molecule that binds to receptors on the very same cell. Which mode of chemical signalling is this?

During wound healing, a cell releases a growth factor that diffuses only as far as the cells directly beside it, stimulating them to divide. Which mode of signalling is this?

Which molecule acts as the SECOND MESSENGER in the signal-transduction pathway studied here?

State the name of the second messenger produced inside the cell after a hydrophilic hormone binds its transmembrane receptor.

A signalling molecule binds to a receptor protein on a target cell. What term is used for the signalling molecule that binds the receptor?

After a neurotransmitter has acted, the signal at the synapse must be switched off. Which event ends the signal?

Which property of a steroid hormone allows it to bind a receptor INSIDE the target cell rather than on the cell surface?

State precisely where a neurotransmitter binds in order to trigger a response in the postsynaptic neuron.

State where the receptor for a peptide hormone such as insulin is located in a target cell.

Acetylcholine is released into the gap between a nerve ending and a muscle fibre and acts on the cell immediately across that gap. Which mode of signalling does this describe?

A transmembrane receptor is best described as a protein that

A neurotransmitter has just been released into the synaptic cleft. What must happen next for the signal to produce a response in the postsynaptic neuron?

State where the receptor for a steroid hormone is located within a target cell.

State the term used for a signalling molecule that binds to a receptor.

Why does a water-soluble signalling molecule have to use a receptor on the cell surface instead of an intracellular receptor?

The diagram shows a control loop regulating a chemical signalling pathway. As the response rises, it acts back on the pathway to reduce further signalling. What type of control is shown, and what is its effect on the response? [Diagram: bio-negative-feedback]

At a particular synapse, a neurotransmitter binds its receptor and opens channels that let Na⁺ flow into the postsynaptic neuron. What is the most likely effect on that neuron?

Compared with signalling through a surface receptor and a second messenger, signalling through an intracellular receptor is best described as:

Switching a gene ON via an intracellular receptor changes the activity of the cell because it leads to a change in which of the following?

Outline how the binding of a neurotransmitter at an excitatory synapse makes the postsynaptic neuron more likely to fire.