AP Biology Module 20 Vocab quiz

Population

All the individuals of a given species that live and reproduce in a particular place; one of several interbreeding groups of organisms of the same species living in the same geographical area.

Signaling molecule

A chemical messenger that functions in cell communication by affecting activities of other cells.

Target cell

A cell that has receptor proteins that can bind to a specific signaling molecule.

Ligand

A signaling molecule with a molecular shape and distribution of charge that allows it to match up with and bind to a complementary receptor protein.

Quorum sensing

Density-dependent production of signal molecules in bacteria that leads to population responses, such as bioluminescence or DNA uptake.

Hormone

A signaling molecule that is transported in the circulatory system by endocrine signaling.

Plasmodesmata

Connections between two adjacent plant cells that permit molecules and other substances to pass directly from the cytoplasm of one cell to the cytoplasm of another.

Sensor

In homeostasis, the component that detects a stimulus.

Set point

In homeostasis, the typical physiological value of a particular parameter, such as body temperature or blood glucose levels, which is actively maintained by the body with very little fluctuation.

Negative feedback

A process in which the response or output of a system opposes the initial stimulus, resulting in steady conditions, or homeostasis.

Positive feedback

A pattern or response in which the output or signal of a communication system increases the activity in the same system that produced the signal.