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Ernest Overton
Charles Ernest Overton (1865–1933) was a British physiologist and biologist, now regarded as a pioneer of the theory of the cell membrane. In the last years of the 19th century Overton did experimental work, allowing the distinction to be drawn between the cell wall of plants and their cytoplasmic membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (th .... He studied the permeability of a range of biological materials to around 500 chemical compounds. In 1900, Overton proposed a biomembrane model "Overton Biomembrane Model" which stated that biomembranes are made up of lipids. He gave this statement on the basis of observation of transport of lipid soluble substances across the biomembranes. He came to Lund University in Sweden as a professor, and married Louise Petrén-Ove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of cells and organelles, being selectively permeable to io ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Wall
A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mechanism. Cell walls are absent in many eukaryotes, including animals, but are present in some other ones like fungi, algae and plants, and in most prokaryotes (except mollicute bacteria). A major function is to act as pressure vessels, preventing over-expansion of the cell when water enters. The composition of cell walls varies between taxonomic group and species and may depend on cell type and developmental stage. The primary cell wall of land plants is composed of the polysaccharides cellulose, hemicelluloses and pectin. Often, other polymers such as lignin, suberin or cutin are anchored to or embedded in plant cell walls. Algae possess cell walls made of glycoproteins and polysaccharides such as carrageenan and agar that are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasmic Membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of cells and organelles, being selectively permeable to ions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semipermeable Membrane
Semipermeable membrane is a type of biological or synthetic, polymeric membrane that will allow certain molecules or ions to pass through it by osmosis. The rate of passage depends on the pressure, concentration, and temperature of the molecules or solutes on either side, as well as the permeability of the membrane to each solute. Depending on the membrane and the solute, permeability may depend on solute size, solubility, properties, or chemistry. How the membrane is constructed to be selective in its permeability will determine the rate and the permeability. Many natural and synthetic materials which are rather thick are also semipermeable. One example of this is the thin film on the inside of the egg. Biological membranes are selectively permeable, with the passage of molecules controlled by facilitated diffusion, passive transport or active transport regulated by proteins embedded in the membrane. Biological membranes An example of a biological semi-permeable membrane i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lund University
, motto = Ad utrumque , mottoeng = Prepared for both , established = , type = Public research university , budget = SEK 9 billion Facts and figures Lund University web site. , head_label = Vice Chancellor , head = Erik Renström , academic_staff = 4,780 (2022) (academic staff, researchers and employed research students) , administrative_staff = 2,890 (2022) , students = 46 000 (29 000 full-time equivalents) [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louise Petrén-Overton
Hedvig Louise Beata Petrén-Overton (August 12, 1880 – January 14, 1977) was a Swedish mathematician, the first woman in Sweden with a doctorate in mathematics. Early life and education Louise Petrén was one of twelve children of the vicar of Halmstad. Her father had earned a doctorate in mathematics in 1850, and her great-uncle had been a professor of mathematics at Lund University. One of her brothers was physician and researcher Karl Anders Petrén. With two older sisters doing the housework, she was left free to concentrate on her studies. As a child, ill with scarlet fever, she told her family that she would not go to heaven unless she could bring her mathematics books there. She earned an education certificate through private tutoring in 1899, and earned a bachelor's degree at Lund University in 1902, as one of roughly a dozen women at the university and the only one in the sciences. She earned a licenciate in 1910 and defended her doctorate at Lund in 1911, with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meyer-Overton Hypothesis
Minimum alveolar concentration or MAC is the concentration, often expressed as a percentage by volume, of a vapour in the alveoli of the lungs that is needed to prevent movement (motor response) in 50% of subjects in response to surgical (pain) stimulus. MAC is used to compare the strengths, or potency, of anaesthetic vapours. The concept of MAC was first introduced in 1965. MAC actually is a ''median'' value, not a minimum as term implies. The original paper proposed MAC as the ''minimal'' alveolar concentration, which was shortly thereafter revised to ''minimum'' alveolar concentration. A lower MAC value represents a more potent volatile anesthetic. Other uses of MAC include MAC-BAR (1.7–2.0 MAC), which is the concentration required to block autonomic reflexes to nociceptive stimuli, and MAC-awake (0.3–0.5 MAC), the concentration required to block voluntary reflexes and control perceptive awareness. Formal definition The MAC is the concentration of the vapour (measured ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1865 Births
Events January–March * January 4 – The New York Stock Exchange opens its first permanent headquarters at 10-12 Broad near Wall Street, in New York City. * January 13 – American Civil War : Second Battle of Fort Fisher: United States forces launch a major amphibious assault against the last seaport held by the Confederates, Fort Fisher, North Carolina. * January 15 – American Civil War: United States forces capture Fort Fisher. * January 31 ** The Thirteenth Amendment to the United States Constitution (conditional prohibition of slavery and involuntary servitude) passes narrowly, in the House of Representatives. ** American Civil War: Confederate General Robert E. Lee becomes general-in-chief. * February ** American Civil War: Columbia, South Carolina burns, as Confederate forces flee from advancing Union forces. * February 3 – American Civil War : Hampton Roads Conference: Union and Confederate leaders discuss peace terms. * Feb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1933 Deaths
Events January * January 11 – Sir Charles Kingsford Smith makes the first commercial flight between Australia and New Zealand. * January 17 – The United States Congress votes in favour of Philippines independence, against the wishes of U.S. President Herbert Hoover. * January 28 – "Pakistan Declaration": Choudhry Rahmat Ali publishes (in Cambridge, UK) a pamphlet entitled ''Now or Never; Are We to Live or Perish Forever?'', in which he calls for the creation of a Muslim state in northwest India that he calls " Pakstan"; this influences the Pakistan Movement. * January 30 ** National Socialist German Workers Party leader Adolf Hitler is appointed Chancellor of Germany by President of Germany Paul von Hindenburg. ** Édouard Daladier forms a government in France in succession to Joseph Paul-Boncour. He is succeeded on October 26 by Albert Sarraut and on November 26 by Camille Chautemps. February * February 1 – Adolf Hitler gives his "Proclamation to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
19th-century British Biologists
The 19th (nineteenth) century began on 1 January 1801 ( MDCCCI), and ended on 31 December 1900 ( MCM). The 19th century was the ninth century of the 2nd millennium. The 19th century was characterized by vast social upheaval. Slavery was abolished in much of Europe and the Americas. The First Industrial Revolution, though it began in the late 18th century, expanding beyond its British homeland for the first time during this century, particularly remaking the economies and societies of the Low Countries, the Rhineland, Northern Italy, and the Northeastern United States. A few decades later, the Second Industrial Revolution led to ever more massive urbanization and much higher levels of productivity, profit, and prosperity, a pattern that continued into the 20th century. The Islamic gunpowder empires fell into decline and European imperialism brought much of South Asia, Southeast Asia, and almost all of Africa under colonial rule. It was also marked by the collapse of the la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Physiologists
British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, the English language as spoken and written in the United Kingdom or, more broadly, throughout the British Isles * Celtic Britons, an ancient ethno-linguistic group * Brittonic languages, a branch of the Insular Celtic language family (formerly called British) ** Common Brittonic, an ancient language Other uses *'' Brit(ish)'', a 2018 memoir by Afua Hirsch *People or things associated with: ** Great Britain, an island ** United Kingdom, a sovereign state ** Kingdom of Great Britain (1707–1800) ** United Kingdom of Great Britain and Ireland (1801–1922) See also * Terminology of the British Isles * Alternative names for the British * English (other) * Britannic (other) * British Isles * Brit (other) * Briton ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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