Glossary: Q-S

Respiration

Definition: A process in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances. Respiration is a three-step process that involves glycolysis, the Krebs cycle, and oxidative phosphorylation.

Examples:

• Glycolysis: The breakdown of glucose into pyruvate, which takes place in the cytoplasm.
• The Krebs cycle: The oxidation of pyruvate to carbon dioxide, which takes place in the mitochondria.
• Oxidative phosphorylation: The production of ATP from the transfer of electrons from NADH and FADH2 to oxygen, which takes place in the mitochondria.

Context/Function: Respiration is the process by which most of the energy in living organisms is produced. It is essential for all life processes, including growth, reproduction, and movement.

Species

Definition: A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. The species is the principal natural taxonomic unit, ranking below a genus and denoted by a Latin binomial, e.g., Homo sapiens.

Examples:

• Humans: Homo sapiens
• Dogs: Canis lupus familiaris
• Cats: Felis catus

Context/Function: The concept of a species is fundamental to biology and to our understanding of the diversity of life on Earth. It is used to classify organisms and to study their evolutionary relationships.