Crowdly

At a synapse Neuroligin and Neurexin function

To tether and then dock vesicles of transmitter

To allow the vesicles to fuse with the cell membrane

To link up across the synapse to promote synaptic efficiency

✅

To move Ca⁺⁺ from the active zone to the docking proteins

To cause the unzipping of the vesicles membranes when they fuse with the terminal membrane

Receptors for water-soluble chemical signals

Can be linked to G proteins and Tyrosine kinase to produce intracellular effects

Only form ion channels and are used for rapid signalling

Produce intermediate duration effects through actions on the DNA

Produce intermediate duration effects through membrane-bound actions on the DNA

Can act via ion channels, G proteins, Tyrosine kinase or DNA to produce intracellular effects

The point at which two excitable cells contact to exchange information with each other is called a

Gap junction

Flash point

Desmosome

Synapse

Tight junctions

Electrical signalling:

Occurs through gap-junction channels.

✅

Involves chemically-gated channels.

Always involves the flow of ions in only one direction.

Involves ion channels activating G proteins.

Occurs by the flow of ions through the extracellular fluid.

Receptor molecules for chemical signals have the property of specificity because:

they are macromolecules made up of amino acids.

their binding sites for a chemical signal have a particular structure.

they can be recycled.

they are membrane-bound.

they have regulatory sites.

At an electrical synapse, presynaptic and postsynaptic membranes interface through

keratinocytes

gap junctions

neurofibril nodes

desmosomes

neurotransmitters

Which of the following statements is true of ALL chemical receptors in cells?

Undergo a conformational change on binding to ligand

Are coupled to a G-protein

Are made up of two or more proteins

Each type can only bind one ligand

Are located on the cell membrane

The mechanisms to reduce a cell's ability to respond to high levels of a chemical are mainly

G protein coupled signalling mechanisms, Increased refractoriness and Decreased affinity

Pre-synaptic inhibition and Pre-synaptic facilitation

Activation of inactivation sites, Down regulation and Sequestration

Pre-synaptic inhibition and Post-synaptic inhibition

Activation of Desensitization sites, Increased refractoriness and Decreased affinity