Cell Communication

These flashcards cover key concepts related to cell communication, including signaling mechanisms, receptor types, and the roles of ligands and second messengers.

What are the four types of signaling mechanisms found in multicellular organisms?

Autocrine, Direct, Paracrine, Endocrine.

What is Autocrine signaling?

A cell targets itself and often occurs during development.

Define Paracrine signaling.

A signaling process where a cell targets a nearby cell.

What distinguishes Endocrine signaling?

It involves the targeting of distant cells via the bloodstream.

What are internal receptors responsible for?

They regulate gene expression by entering the nucleus and binding to DNA.

What characterizes cell-surface receptors?

They are transmembrane receptors specific to individual cells with extracellular, transmembrane, and intracellular domains.

How do G-protein linked receptors function?

They are activated by ligand binding, inducing a conformational change that activates G-proteins.

What is the role of tyrosine kinase in cell signaling?

Ligand binding causes dimerization of receptors, activating tyrosine kinase, which leads to phosphorylation inside the cell.

Define second messengers in signal transmission.

Small molecules that propagate a signal after ligand binding, such as calcium and cyclic AMP (cAMP).

How does phosphorylation affect intracellular signaling?

It can activate or inactivate proteins, affecting cell responses.

What is quorum sensing in bacteria?

A signaling mechanism that allows bacteria to monitor cell density and respond to environmental changes.

What role does apoptosis play in cellular processes?

It is essential for life and development, impacting gene expression and metabolism.

What happens during signal transduction?

The continuation of a signal from the ligand receptor to inside the cell, often involving second messengers.

What are the two main types of ligands based on their solubility?

Small hydrophobic ligands and water-soluble ligands.

What is the significance of signaling via gap junctions?

It allows cells to coordinate responses through direct intercellular communication.