Cell Communication - Chapter 9

Practice flashcards covering key concepts from Chapter 9 on cell communication.

What is cell communication?

The process by which cells send messages to each other.

What is quorum sensing?

A mechanism for cells to monitor local cell density.

What is a ligand?

A signaling molecule that binds to a receptor protein.

What role does the receptor protein play in cell communication?

It binds to the ligand to initiate a cellular response.

What is signal transduction?

The process that converts the information in a signal into a cellular response.

Name the four basic mechanisms for cellular communication.

Direct contact, paracrine signaling, endocrine signaling, and synaptic signaling.

What is paracrine signaling?

When a signal released from a cell affects neighboring cells.

Describe synaptic signaling.

Occurs in animals where nerve cells release neurotransmitters to bind receptors on nearby target cells.

What is the difference between intracellular receptors and cell-surface receptors?

Intracellular receptors are inside the cell and bind small, hydrophobic ligands, while cell-surface receptors are on the plasma membrane and bind hydrophilic ligands.

What is phosphorylation in the context of signaling?

The addition of a phosphate group to a protein to change its activity.

What is the function of protein kinases?

Enzymes that add phosphate groups to proteins, often activating them.

How do G protein-coupled receptors work?

They link extracellular signals to intracellular responses by activating G proteins.

What are second messengers?

Molecules that relay signals inside cells, amplifying the signal from a receptor.

How do glucagon and epinephrine stimulate liver cells?

Both hormones can activate the same signaling pathway to mobilize glucose.

What is the significance of receptor subtypes?

Different forms of the same receptor can lead to different effects in different cells.

How do receptor tyrosine kinases (RTKs) function in cell signaling?

They dimerize and autophosphorylate upon ligand binding, initiating a cellular response.

What is a MAP kinase cascade?

A series of protein kinases that phosphorylate each other in succession, amplifying a signal.

What do scaffold proteins do in signaling pathways?

They organize the components of a kinase cascade into a single protein complex for efficiency.

What is the role of Ras protein in signaling?

Ras acts as a link between receptor tyrosine kinases and the MAP kinase cascade.