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Cellular respiration is the process of which biological fuels are oxidised in the presence of an inorganic electron acceptor such as oxygen to produce large amounts of energy, to drive the bulk production of ATP. Anaerobic respiration is used by microorganisms either bacteria or archaea in which neither oxygen (aerobic respiration) nor pyruvate ...
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary ...
Ventilation refers to the in-and-out movement of air of the lungs and perfusion is the circulation of blood in the pulmonary capillaries. [1] In mammals, physiological respiration involves respiratory cycles of inhaled and exhaled breaths. Inhalation (breathing in) is usually an active movement that brings air into the lungs where the process ...
List of first human settlements. This is a list of dates associated with the prehistoric peopling of the world (first known presence of Homo sapiens ). The list is divided into four categories, Middle Paleolithic (before 50,000 years ago), Upper Paleolithic (50,000 to 12,500 years ago), Holocene (12,500 to 500 years ago) and Modern ( Age of ...
These are lists of the 100 known verified oldest women and men sorted in descending order by age in years and days. [ a] The oldest person ever whose age has been independently verified is Jeanne Calment (1875–1997) of France, who lived to the age of 122 years and 164 days. [ b] The oldest verified man ever is Jiroemon Kimura (1897–2013) of ...
Ecosystem respiration is the sum of all respiration occurring by the living organisms in a specific ecosystem. [1] The two main processes that contribute to ecosystem respiration are photosynthesis and cellular respiration. Photosynthesis uses carbon-dioxide and water, in the presence of sunlight to produce glucose and oxygen whereas cellular ...
Demographics of the world. Demographics of Earth. Population pyramid of the world in 2022 by the UN. Population. Over 8,120,531,329 (estimated) Fertility rate. 2.27 (2021) Earth has a human population of over 8 billion as of 2024, with an overall population density of 50 people per km 2 (130 per sq. mile). Nearly 60% of the world's population ...
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of organisms. Cell biology is the study of the structural and functional units of cells. Cell biology encompasses both prokaryotic and ...