Cell Communication

These flashcards cover essential concepts related to cell communication, including signaling pathways, receptor types, and specific signaling molecules.

What are the two main pathways of cell communication?

Extracellular Reception and Intracellular Reception.

What is the role of signal molecules in cell communication?

Signal molecules bind to receptor proteins to initiate a signaling cascade.

What types of signaling mechanisms are involved in extracellular signal types?

Contact-dependent, paracrine, synaptic, and endocrine signaling.

What is the significance of having many simultaneous signals in cell communication?

Different receptors can lead to different responses, allowing for complex cellular signaling.

What types of receptors are involved in extracellular signaling?

Ion-channel coupled, G-protein linked, and enzyme-linked receptors.

What is a G-protein and its function?

G-proteins act as molecular switches that transmit signals from outside the cell into the cell.

What occurs when a signal molecule binds to a G-protein linked receptor?

The G-protein exchanges GDP for GTP and gets activated.

What is the role of cAMP in cellular processes?

cAMP acts as a mediator, influencing various cellular functions.

What happens to protein kinase A (PKA) when cAMP levels rise?

cAMP binds to regulatory sites on PKA, activating its catalytic subunits.

How does nitric oxide function as a signaling molecule?

NO diffuses into target cells and activates guanyl cyclase, converting GTP to cGMP.

What is the cellular effect of nitric oxide on muscle cells?

Nitric oxide causes rapid relaxation of smooth muscle cells.

What are inositol phosphates and their role in cell signaling?

Inositol phosphates are products of phospholipase C activation and serve as secondary messengers.

What is the function of calmodulin in cellular signaling?

Calmodulin binds Ca2+ and activates various proteins, including kinases.

What triggers the production of nitric oxide in cells?

Acetylcholine released from nerve cells stimulates nitric oxide synthesis.

What is the lifespan of nitric oxide as a signaling molecule?

Nitric oxide has a very short half-life of 5-10 seconds.

What is the primary target of nitric oxide in cells?

Guanyl cyclase, which converts GTP into cyclic GMP.

What cellular processes does cyclic GMP mediate?

Cyclic GMP mediates multiple processes like vasodilation and smooth muscle relaxation.

What is the consequence of G-protein hydrolyzing GTP?

The G-protein is inactivated and reassociates into its trimeric form.