Key Terms from Biology Lecture: Theory, Disease, and Living Organisms

Vocabulary flashcards covering key concepts from the lecture notes, including terms related to theory, disease, living organisms, cell structure, and geological evidence.

purchase (contextual definition)

In the lecture, purchase means gaining traction on an issue or arriving at a conclusion, not buying.

theory

A well-supported explanation based on a wealth of evidence accumulated over years; not a guess.

disease

A specific pathological condition with a known cause (etiology); examples include cancer, Alzheimer's, Huntington's, cystic fibrosis, AIDS.

illness

A general term for a state of being unwell; used when disease is not defined or specified.

idiopathic

Having an unknown cause; etiology that is not yet understood.

plasma membrane

The cell boundary that encloses the interior, maintains the internal environment, and regulates movement of water and substances.

stimulus

A signal (external or internal) that elicits a response from an organism.

response

The organism’s action or change in behavior in reaction to a stimulus.

unicellular

Organisms composed of a single cell.

multicellular

Organisms composed of many cells, with specialized tissues.

germ theory

The idea that many diseases are caused by microorganisms and can be studied scientifically.

osmosis

Movement of water across a semipermeable membrane, driven by differences in solute concentration.

first law of thermodynamics

Energy cannot be created or destroyed, only transformed; total energy in a closed system remains constant.

exothermic

A chemical reaction that releases heat to the surroundings, often releasing energy rather than providing it for work.

Chicxulub crater

A meteorite impact crater in the Yucatán Peninsula; linked to a mass extinction and evidenced by iridium layers and gravity anomalies.

iridium anomaly

Unusually high iridium concentrations in rocks, indicating a meteorite impact event.

gravity mapping

Mapping subtle variations in Earth's gravitational field to identify features like craters and buried structures.