Cellular respiration is the process by which cells break down glucose and other molecules to produce energy in the form of ATP. The spelling of this word can be explained using the International Phonetic Alphabet (IPA) phonetic transcription. The first syllable, "cell," is pronounced as "sɛl" and refers to a small, enclosed space. The second syllable, "u-lar," is pronounced as "juːlər" and means "related to," indicating that the process occurs within cells. The final syllables, "res-pi-ra-tion," are pronounced as "rɛspəˈreɪʃən" and refer to the act of breathing or exchanging gases.
Cellular respiration is a vital biochemical process that occurs in the cells of living organisms, especially in eukaryotic organisms, to generate energy in the form of adenosine triphosphate (ATP). It is an intricate metabolic pathway that involves the oxidation of glucose or other organic molecules within the cells, releasing energy for various life processes.
During cellular respiration, glucose is broken down through a series of complex reactions involving enzymes and electron transport chains. These reactions occur in three main stages: glycolysis, the Krebs cycle (also known as the citric acid cycle or TCA cycle), and oxidative phosphorylation (electron transport chain).
Glycolysis is the initial step where glucose is converted into two molecules of pyruvate, producing a small amount of ATP and reducing substances like NADH. The next stage, the Krebs cycle, takes place within the mitochondria, breaking down pyruvate to generate more NADH and FADH2, as well as ATP and release carbon dioxide. Ultimately, the electron transport chain uses electrons carried by NADH and FADH2 to produce a large amount of ATP through oxidative phosphorylation.
Overall, cellular respiration is crucial for the survival and functioning of living cells as it provides energy needed for essential processes like growth, movement, metabolism, and reproduction. It is an efficient way to convert the chemical energy stored in glucose and other organic molecules into a more usable form (ATP) that can be readily utilized by the cell.
The word "cellular" in "cellular respiration" refers to cells, which are the smallest units of life. It comes from the Latin word "cellula", meaning "small room" or "small compartment". This term was used by Robert Hooke, an English scientist, in the late 17th century to describe the tiny compartments he observed under a microscope.
The word "respiration" comes from the Latin word "respirare", meaning "to breathe". It refers to the process in which living organisms take in oxygen and release carbon dioxide. This term has been used since ancient times to describe the act of breathing and the exchange of gases in organisms.
Therefore, the combination of "cellular" and "respiration" in the term "cellular respiration" indicates the process of breaking down organic molecules within cells to release energy, using oxygen and producing carbon dioxide as byproducts.