AP Bio Unit 4

Cell Communication

The process by which cells can communicate with each other via various methods including direct contact, local signaling, and long distance signaling.

Direct Contact

Gap Junctions, and Plasmodesmata

Plasmodesmata

Channels that connect plant cells, allowing for direct communication and transport of substances.

Gap Junctions

Specialized intercellular connections in animal cells that allow direct communication between neighboring cells.

Local Signaling

Paracrine, Synaptic

Paracrine signaling

A form of local signaling where the target cell is close to the signal-releasing cell.

Synaptic signaling

A type of local signaling that occurs in the nervous system, involving neurotransmitters at synapses.

Long Distance

Endocrine

Endocrine system

A system of glands that secrete hormones into the bloodstream for long-distance signaling.

Ligand

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

Transduction

The process by which a signal is converted into a cellular response. Extracellular to Intracelllular

Cyclic AMP

A second messenger molecule that amplifies signals and activates multiple proteins within a cell.

GPCR (G Protein-Coupled Receptor)

A large family of receptors that detect molecules outside the cell and activate internal signal transduction pathways.

Ion Channels

Proteins that form pores in the cell membrane, allowing ions to flow in and out of cells, often activated by ligands.

Negative Feedback

A regulatory mechanism in which a change in a variable triggers a response that counteracts the initial change to maintain homeostasis.

Positive Feedback

A regulatory process in which an increase in a variable triggers further increases, pushing systems further away from their set point.

Cell Cycle

The series of phases that a cell goes through leading to its division and replication, including G1, S, G2, and mitosis.

Apoptosis

Programmed cell death that occurs in the body as a natural part of growth and development.

Cyclins

Regulatory proteins that control the progression of the cell cycle by activating cyclin-dependent kinases (CDKs).

Cyclin-dependent kinase (CDK)

Enzymes that, when activated by cyclins, progress the cell cycle and regulate various functions.

Checkpoints in the Cell Cycle

Regulatory points in the cell cycle that ensure proper division and prevent errors.