Cell Signaling Routes, Receptors, and Ligand Properties

All flashcards

What do intercellular and intracellular mean?

Intercellular means communication between cells; intracellular means communication within a cell.

What are a ligand, receptor, and target cell?

A ligand is a signaling molecule that binds a specific molecule. A receptor recognizes and binds a ligand, and a target cell is a cell affected by the signal.

How does signaling across a chemical synapse work?

An impulse reaching the presynaptic axon terminal causes neurotransmitters to be released. They cross the small synaptic gap, bind receptors on the postsynaptic cell, and can initiate another impulse.

How does endocrine signaling reach distant targets?

Endocrine cells release hormones that travel through the bloodstream to target cells elsewhere in the body. The response is often slower but longer-lasting.

What passes through gap junctions and plasmodesmata?

Small signaling molecules and ions, such as calcium ions, can pass between connected cells; large molecules such as proteins and DNA cannot.

Quiz questions

1. What immediate effect can ligand binding have on an ion channel-linked receptor?Answer: It opens or alters a channel, allowing selected ions to cross.
2. What nucleotide change activates a G protein after receptor activation?Answer: GDP is released and GTP binds to the G protein.
3. What commonly happens when a tyrosine kinase receptor is activated by ligand binding?Answer: Two receptors dimerize and phosphorylate tyrosine residues.
4. Why do hydrophobic hormones often bind carrier proteins while traveling in blood?Answer: Carrier proteins help them travel through watery blood.
5. How can differences in cell-surface receptors affect which host species a virus can infect?Answer: Receptor differences can prevent viral proteins from binding host cells.