AP Biology cell communication key terms

What is cell signaling?

The process by which cells communicate with each other using chemical signals.

Difference between endocrine and paracrine signaling

Endocrine signaling involves hormones traveling through the bloodstream; paracrine signaling occurs between nearby cells.

What is a ligand?

A molecule that binds to a receptor to initiate a cellular response.

True or false: Receptors are only found on the cell surface.

False, because some receptors are intracellular and found within the cytoplasm or nucleus.

Function of G protein-coupled receptors

They transmit signals from outside the cell to inside, activating G proteins.

Fill in the blank: __________ signaling involves direct contact between cells.

Juxtacrine

What are second messengers?

Small molecules that propagate a signal within a cell after receptor activation, e.g., cAMP.

Which molecule often acts as a second messenger?

Cyclic AMP (cAMP) is a common second messenger in signal transduction pathways.

True or false: All signaling pathways result in a cellular response.

False, because some pathways may not lead to an immediate response or may be inhibitory.

Difference between autocrine and paracrine signaling

Autocrine signaling affects the same cell that releases the signal; paracrine affects nearby cells.

What is signal transduction?

The process by which a cell converts an extracellular signal into a functional response.

What role do protein kinases play?

They add phosphate groups to proteins, altering their activity as part of signaling pathways.

Fill in the blank: __________ signaling involves hormones traveling through the bloodstream.

Endocrine

What is apoptosis?

Programmed cell death, often triggered by specific signaling events.

True or false: All receptors are specific to one ligand.

True, because receptor-ligand interactions are highly specific and crucial for proper signaling.

What is the role of phosphatases?

They remove phosphate groups from proteins, often reversing the actions of kinases.

Define neurotransmitters.

Chemical messengers that transmit signals across a synapse from one neuron to another.

What is a signal amplification?

The process by which a small signal results in a large response through a cascade of reactions.

Difference between ion channel-linked and G protein-coupled receptors

Ion channel-linked receptors allow ions to flow across membranes; G protein-coupled receptors activate G proteins.

What is a feedback loop?

A process in which the output of a system influences its own activity, can be positive or negative.

Fill in the blank: __________ signaling allows cells to respond to their environment.

Cellular

What is a receptor tyrosine kinase (RTK)?

A type of receptor that, upon binding a ligand, dimerizes and autophosphorylates to activate signaling pathways.

What is the primary function of integrins?

To mediate cell adhesion to the extracellular matrix and transmit signals from the ECM to the cell.

True or false: All cell signals require a receptor.

True, because signals must bind to receptors to elicit a cellular response.

What is the significance of cell communication?

It allows cells to coordinate activities, respond to changes, and maintain homeostasis.