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Topic Review
Biography
Topic Review
Niacin
Niacin (also known as “vitamin B3” or “vitamin PP”) includes two vitamers (nicotinic acid and nicotinamide) giving rise to the coenzymatic forms nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP).
2.0K
17 Feb 2022
Topic Review
Sex Organ
A sex organ (or reproductive organ) is any part of an animal's body that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. The testis in the male, and the ovary in the female, are called the primary sex organs. All others are called secondary sex organs, divided between the external sex organs—the genitals or genitalia, visible at birth in both sexes—and the internal sex organs. Mosses, ferns, and some similar plants have gametangia for reproductive organs, which are part of the gametophyte. The flowers of flowering plants produce pollen and egg cells, but the sex organs themselves are inside the gametophytes within the pollen and the ovule. Coniferous plants likewise produce their sexually reproductive structures within the gametophytes contained within the cones and pollen. The cones and pollen are not themselves sexual organs.
2.0K
04 Nov 2022
Topic Review
Senescence
Plants not only may delay senescence until after they reproduce successfully, but they may also bring senescence time forward, in order to reproduce in favored conditions. It demonstrates that even though senescence is part of aging, it does not necessarily mean plants have to reach a certain age to senesce. Experiments using different aged plants have suggested that in interest of their final outcome and fitness, plants carefully weigh out environmental cues and transit to next developmental phase at proper time, even if that means transiting to terminal senescence phase earlier and shortening their lifespan.
2.0K
20 Feb 2021
Topic Review
Nitrogen in Wetlands
Wetlands are viable sinks for nitrate and have also been identified as a source of nitrous oxide, a product of two microbially regulated processes: nitrification and denitrification. Anthropogenic expansion of nitrogen is a leading cause of the eutrophication of water bodies and may also contribute to the deterioration of the ozone layer in the stratosphere. Wetlands ameliorate the quality of water percolating through them, by retaining nutrients and sequestering carbon, and simultaneously enhancing the flora and fauna diversity of these landscapes. Among the many services these wetlands provide, they also alleviate nitrate pollution by attenuating reactive nitrogen from agricultural drainage and ensure the effective reclamation of the wastewater.
2.0K
24 May 2021
Topic Review
Trans-Fatty Acids
Naturally occurring (fatty acids) FAs usually have the cis-configuration. Nevertheless, under certain conditions (e.g. partial catalytic hydrogenation or enzymatic hydrogenation), a double bond in FAs may change from a cis (Z) to a trans (E) configuration (geometric isomerization) and/or move to other positions in the carbon chain (positional isomerization). TFAs mediate increase of LDL levels and decrease of HDL levels in blood, which may lead to health consequences (e.g. cardiovascular diseases), even if this association is unclear considering the small proportion (about 10%) of cholesterol participating in atherosclerosis, re-questioning the interest of statins in this context. However, awareness is strongly suggested about industrial hydrogenation and subsequently possible excessive consumption of deleterious TFAs.
2.0K
28 Dec 2020
Biography
Hans Adolf Krebs
Sir Hans Adolf Krebs (/krɛbz, krɛps/; 25 August 1900 – 22 November 1981)[1][2][3][4] was a German-born British biologist, physician and biochemist.[5] He was a pioneer scientist in the study of cellular respiration, a biochemical process in living cells that extracts energy from food and oxygen and makes it available to drive the processes of life.[6][7] He is best known for his discoveries
2.0K
29 Nov 2022
Topic Review
Long-Term Memory
Long-term memory (LTM) is the stage of the Atkinson–Shiffrin memory model in which informative knowledge is held indefinitely. It is defined in contrast to short-term and working memory, which persist for only about 18 to 30 seconds. Long-term memory is commonly labelled as explicit memory (declarative), as well as episodic memory, semantic memory, autobiographical memory, and implicit memory (procedural memory).
2.0K
24 Nov 2022
Topic Review
Tree of Life
The tree of life or universal tree of life is a metaphor, model and research tool used to explore the evolution of life and describe the relationships between organisms, both living and extinct, as described in a famous passage in Charles Darwin's On the Origin of Species (1859). {{Blockquote Tree diagrams originated in the medieval era to represent genealogical relationships. Phylogenetic tree diagrams in the evolutionary sense date back to the mid-nineteenth century. The term phylogeny for the evolutionary relationships of species through time was coined by Ernst Haeckel, who went further than Darwin in proposing phylogenic histories of life. In contemporary usage, tree of life refers to the compilation of comprehensive phylogenetic databases rooted at the last universal common ancestor of life on Earth. Two public databases for the tree of life are TimeTree, for phylogeny and divergence times, and the Open Tree of Life, for phylogeny.
2.0K
18 Oct 2022
Topic Review
The Role of Phytoplankton in Carbon Dioxide Fixation
Marine phytoplankton account for more than half of the carbon dioxide fixation of Earth. The export of carbon is highest at the photic zone of the ocean, which is dominated by phytoplankton. The term phytoplankton comes from the Greek words phyto (plants) and plankton (wanderers or drifters). Plankton can also be zooplanktons that feed on phytoplankton and release fecal pellets that are made of dissolved carbon particles.
2.0K
13 Apr 2022
Biography
Frank Macfarlane Burnet
Sir Frank Macfarlane Burnet, OM AK KBE FRS FAA FRSNZ[1] (3 September 1899 – 31 August 1985[2]), usually known as Macfarlane or Mac Burnet, was an Australian virologist best known for his contributions to immunology. He won a Nobel Prize in 1960 for predicting acquired immune tolerance and was best known for developing the theory of clonal selection. Burnet received his Doctor of Medicine degr
2.0K
30 Dec 2022
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