background preloader


The Archaea ( Archaea were initially classified as bacteria, receiving the name archaebacteria (or Kingdom Monera), but this classification is outdated.[1] Archaeal cells have unique properties separating them from the other two domains of life: Bacteria and Eukaryota. The Archaea are further divided into four recognized phyla. Classification is difficult, because the majority have not been studied in the laboratory and have only been detected by analysis of their nucleic acids in samples from their environment. Classification[edit] New domain[edit] Current classification[edit] The classification of archaea, and of prokaryotes in general, is a rapidly moving and contentious field. A superphylum - TACK - has been proposed that includes the Aigarchaeota, Crenarchaeota, Korarchaeota and Thaumarchaeota.[18] This superphylum may be related to the origin of eukaryotes. Species[edit] The classification of archaea into species is also controversial. Origin and evolution[edit] R.S. Morphology[edit] Related:  MICROBIOLOGYThe Biology of Life

10 Strange Things About The Universe Space The universe can be a very strange place. While groundbreaking ideas such as quantum theory, relativity and even the Earth going around the Sun might be commonly accepted now, science still continues to show that the universe contains things you might find it difficult to believe, and even more difficult to get your head around. Theoretically, the lowest temperature that can be achieved is absolute zero, exactly ? One of the properties of a negative-energy vacuum is that light actually travels faster in it than it does in a normal vacuum, something that may one day allow people to travel faster than the speed of light in a kind of negative-energy vacuum bubble. One prediction of Einstein’s theory of general relativity is that when a large object moves, it drags the space-time around it, causing nearby objects to be pulled along as well. Relativity of Simultaneity Since this extra dimension is so small, only tiny objects, such as particles, can move along it. Antimatter Retrocausality

Bacteria Bacteria ( Most bacteria have not been characterised, and only about half of the bacterial phyla have species that can be grown in the laboratory.[10] The study of bacteria is known as bacteriology, a branch of microbiology. Etymology Origin and early evolution Morphology Many bacterial species exist simply as single cells, others associate in characteristic patterns: Neisseria form diploids (pairs), Streptococcus form chains, and Staphylococcus group together in "bunch of grapes" clusters. Even more complex morphological changes are sometimes possible. Cellular structure Structure and contents of a typical gram-positive bacterial cell (seen by the fact that only one cell membrane is present). Intracellular structures The bacterial cell is surrounded by a cell membrane (also known as a lipid, cytoplasmic or plasma membrane). Many important biochemical reactions, such as energy generation, use concentration gradients across membranes. Extracellular structures Endospores Growth and reproduction

Prokaryote Cell structure of a bacterium , one of the two domains of prokaryotic life. The division to prokaryotes and eukaryotes reflects two distinct levels of cellular organization rather than biological classification of species. Prokaryotes include two major classification domains: the bacteria and the archaea . [ edit ] Relationship to eukaryotes The division to prokaryotes and eukaryotes is usually considered the most important distinction among organisms. The genome in a prokaryote is held within a DNA / protein complex in the cytosol called the nucleoid , which lacks a nuclear envelope . [ 5 ] The complex contains a single, cyclic, double-stranded molecule of stable chromosomal DNA, in contrast to the multiple linear, compact, highly organized chromosomes found in eukaryotic cells. Prokaryotes lack distinct mitochondria and chloroplasts . [ edit ] Sociality While prokaryotes are still commonly imagined to be strictly unicellular, most are capable of forming stable aggregate communities.

Cell nucleus HeLa cells stained for the cell nucleus DNA with the BlueHoechst dye. The central and rightmost cell are in interphase, thus their entire nuclei are labeled. On the left, a cell is going through mitosis and its DNA has condensed. Because the nuclear membrane is impermeable to large molecules, nuclear pores are required that regulate nuclear transport of molecules across the envelope. The pores cross both nuclear membranes, providing a channel through which larger molecules must be actively transported by carrier proteins while allowing free movement of small molecules and ions. History[edit] Between 1877 and 1878, Oscar Hertwig published several studies on the fertilization of sea urchin eggs, showing that the nucleus of the sperm enters the oocyte and fuses with its nucleus. Structures[edit] Nuclear envelope and pores[edit] Nuclear pores, which provide aqueous channels through the envelope, are composed of multiple proteins, collectively referred to as nucleoporins. Nuclear lamina[edit]

Lyapunov fractal Standard Lyapunov logistic fractal with iteration sequence AB, in the region [2, 4] × [2, 4]. Generalized Lyapunov logistic fractal with iteration sequence AABAB, in the region [2, 4] × [2, 4]. Generalized Lyapunov logistic fractal with iteration sequence BBBBBBAAAAAA, in the growth parameter region (A,B) in [3.4, 4.0] × [2.5, 3.4], known as Zircon Zity. In mathematics, Lyapunov fractals (also known as Markus–Lyapunov fractals) are bifurcational fractals derived from an extension of the logistic map in which the degree of the growth of the population, r, periodically switches between two values A and B. A Lyapunov fractal is constructed by mapping the regions of stability and chaotic behaviour (measured using the Lyapunov exponent ) in the a−b plane for given periodic sequences of a and b. (stability), and blue corresponds to (chaos). Properties[edit] Lyapunov fractals are generally drawn for values of A and B in the interval . Algorithm for generating Lyapunov fractals[edit]

List of Prokaryotic names with Standing in Nomenclature LPSN (formerly List of Bacterial names with Standing in Nomenclature LBSN) Eukaryote Eukaryotes can reproduce both asexually through mitosis and sexually through meiosis and gamete fusion. In mitosis, one cell divides to produce two genetically identical cells. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells each with half the number of chromosomes as the original parent cell (haploid cells). These act as sex cells (gametes – each gamete has just one complement of chromosomes, each a unique mix of the corresponding pair of parental chromosomes) resulting from genetic recombination during meiosis. Cell features[edit] Eukaryotic cells are typically much larger than those of prokaryotes. Internal membrane[edit] Detail of the endomembrane system and its components A 3D rendering of an animal cell cut in half. The nucleus is surrounded by a double membrane (commonly referred to as a nuclear membrane or nuclear envelope), with pores that allow material to move in and out. Vesicles may be specialized for various purposes.

Mitochondrion Two mitochondria from mammalian lung tissue displaying their matrix and membranes as shown by electron microscopy History[edit] The first observations of intracellular structures that probably represent mitochondria were published in the 1840s.[13] Richard Altmann, in 1894, established them as cell organelles and called them "bioblasts".[13] The term "mitochondria" itself was coined by Carl Benda in 1898.[13] Leonor Michaelis discovered that Janus green can be used as a supravital stain for mitochondria in 1900. In 1939, experiments using minced muscle cells demonstrated that one oxygen atom can form two adenosine triphosphate molecules, and, in 1941, the concept of phosphate bonds being a form of energy in cellular metabolism was developed by Fritz Albert Lipmann. The first high-resolution micrographs appeared in 1952, replacing the Janus Green stains as the preferred way of visualising the mitochondria. In 1967, it was discovered that mitochondria contained ribosomes. Structure[edit]

Philosopher's stones | psychedelics | smart shop Philosopher's stones, psilocybe tampanensis, truffles: The psilocybe tampanensis is a special kind of psychedelic mushroom. All the available cultures originate from one specimen, that was cloned in 1977 by mycologist Stephen Pollock, as she has only been found twice in nature. This particular mushroom was found in Tampa, florida, hence the name: Tampanensis. This strain is capable of producing, besides mushrooms, socalled sclerotia they are also known as stones or truffles. Effect of Philosopher's stones, psilocybe tampanensis, truffles: The trip you get from the Philosopher's Stones is very different from other mushrooms. Usage of Philosopher's stones, psilocybe tampanensis, truffles: Eat the Philosopher's Stones, so that the active substance will be absorbed in your body through your mouth. Make tea from the Philosopher's Stones, Boil some water, keep the fire low and leave the truffles in for about 20 minutes. Take truffles on a empty stomach in a quiet natural environment or at home.

Biofilm IUPAC definition Aggregate of microorganisms in which cells that are frequently embedded within a self-produced matrix of extracellular polymeric substance (EPS) adhere to each other and/or to a surface. Note 1: A biofilm is a fixed system that can be adapted internally to environmental conditions by its inhabitants. Note 2: The self-produced matrix of extracellular polymeric substance, which is also referred to as slime, is a polymeric conglomeration generally composed of extracellularbiopolymers in various structural forms.[1] Microbes form a biofilm in response to many factors, which may include cellular recognition of specific or non-specific attachment sites on a surface, nutritional cues, or in some cases, by exposure of planktonic cells to sub-inhibitory concentrations of antibiotics.[4][5] When a cell switches to the biofilm mode of growth, it undergoes a phenotypic shift in behavior in which large suites of genes are differentially regulated.[6] Formation[edit] Development[edit]

Evolution of cells The first cells[edit] The origin of cells was the most important step in the evolution of life on Earth. The birth of the cell marked the passage from pre-biotic chemistry to partitioned units resembling modern cells. If life is viewed from the point of view of replicator molecules, cells satisfy two fundamental conditions: protection from the outside environment and confinement of biochemical activity. Partitioning may have begun from cell-like spheroids formed by proteinoids, which are observed by heating amino acids with phosphoric acid as a catalyst. Another possibility is that the shores of the ancient coastal waters may have served as a mammoth laboratory, aiding in the countless experiments necessary to bring about the first cell. Phospholipids are composed of a hydrophilic head on one end, and a hydrophobic tail on the other. [edit] The eukaryotic cell seems to have evolved from a symbiotic community of prokaryotic cells. Genetic code and the RNA world[edit] Quotes[edit]