query: the function of cell division in unicellular organisms

pos: Cell division in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor. Prokaryotes (bacteria) undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication. For simple unicellular microorganisms such as the amoeba, one cell division is equivalent to reproduction – an

pos: Cell (biology) into two daughter cells. This leads to growth in multicellular organisms (the growth of tissue) and to procreation (vegetative reproduction) in unicellular organisms. Prokaryotic cells divide by binary fission, while eukaryotic cells usually undergo a process of nuclear division, called mitosis, followed by division of the cell, called cytokinesis. A diploid cell may also undergo meiosis to produce haploid cells, usually four. Haploid cells serve as gametes in multicellular organisms, fusing to form new diploid cells. DNA replication, or the process of duplicating a cell's genome, always happens when a cell divides through mitosis or binary fission. This occurs during

pos: Bacteria bacteria are largely responsible for the production of the highly toxic forms of mercury (methyl- and dimethylmercury) in the environment. Non-respiratory anaerobes use fermentation to generate energy and reducing power, secreting metabolic by-products (such as ethanol in brewing) as waste. Facultative anaerobes can switch between fermentation and different terminal electron acceptors depending on the environmental conditions in which they find themselves. Unlike in multicellular organisms, increases in cell size (cell growth) and reproduction by cell division are tightly linked in unicellular organisms. Bacteria grow to a fixed size and then reproduce through binary fission, a form of asexual reproduction. Under

pos: Disposable soma theory of aging in stem cell exhaustion, another theorized mechanism of aging. The mechanism of why reproduction inhibits lifespan with regards to multicellular organisms is still unclear. Although many models do illustrate an inverse relationship, and the theory makes sense from an evolutionary perspective, the cellular mechanisms have yet to be explored. However, with regards to cellular replication, the progressive shortening of telomeres is a mechanism which limits the amount of generations of a single cell may undergo. Furthermore, in unicellular organisms like "Saccharomyces cerevisiae", the formation of extrachromosomal rDNA circles (ERCs) in mother cells (but not daughter cells) upon every subsequent division

pos: Asexual reproduction of meiosis and the protective recombinational repair of DNA damage afforded as one function of meiosis. An important form of fission is binary fission, where the parent organism is replaced by two daughter organisms, because it literally divides in two. Only prokaryotes (the archaea and the bacteria) reproduce asexually through binary fission. Eukaryotes (such as protists and unicellular fungi) may reproduce in a functionally similar manner by mitosis; most of these are also capable of sexual reproduction. Multiple fission at the cellular level occurs in many protists, e.g. sporozoans and algae. The nucleus of the parent cell divides several times

pos: Cell division in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor. Prokaryotes (bacteria) undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication. For simple unicellular microorganisms such as the amoeba, one cell division is equivalent to reproduction – an

pos: Evolutionary history of life Sexual reproduction eliminates such rogue cells from the next generation and therefore appears to be a prerequisite for complex multicellularity. The available evidence indicates that eukaryotes evolved much earlier but remained inconspicuous until a rapid diversification around 1 Ga. The only respect in which eukaryotes clearly surpass bacteria and archaea is their capacity for variety of forms, and sexual reproduction enabled eukaryotes to exploit that advantage by producing organisms with multiple cells that differed in form and function. By comparing the composition of transcription factor families and regulatory network motifs between unicellular organisms and multicellular organisms, scientists found there are

pos: Pinnularia cell size of a "Pinnularia" population gradually becomes smaller. When a minimum average size is reached auxospore formation occurs and sexual reproduction restores the population's average cell size. Pinnularia Pinnularia is a fresh water alga more specifically a type of Bacillariophyta (diatom). "Pinnularia" is a predominantly fresh-water alga, usually found in ponds and moist soil. They can also be found in springs, estuaries, sediments, and oceans. Members of this genus are most commonly found in of water, at . "Pinnularia" are elongated elliptical unicellular organisms. Their cell walls are composed chiefly of pectic substances on a rigid silica framework. Their

pos: Cell signaling or internalized by the receiving organism. In some cases of interspecies signaling, the emitting organism can actually be a host of the receiving organism, or vice versa. Intraspecies signaling occurs especially in bacteria, yeast, social insects, but also many vertebrates. The signaling molecules used by multicellular organisms are often called pheromones. They can have such purposes as alerting against danger, indicating food supply, or assisting in reproduction. In unicellular organisms such as bacteria, signaling can be used to 'activate' peers from a dormant state, enhance virulence, defend against bacteriophages, etc. In quorum sensing, which is also found in social insects,

neg: Unicellular organism thrush) and vagina (commonly called yeast infection). Most unicellular organisms are of microscopic size and are thus classified as microorganisms. However, some unicellular protists and bacteria are macroscopic and visible to the naked eye. Examples include: Unicellular organism A unicellular organism, also known as a single-celled organism, is an organism that consists of only one cell, unlike a multicellular organism that consists of more than one cell. Unicellular organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. Prokaryotes include bacteria and archaea. Many eukaryotes are multicellular, but the group includes the protozoa, unicellular algae, and unicellular fungi. Unicellular

neg: Unicellular organism Unicellular organism A unicellular organism, also known as a single-celled organism, is an organism that consists of only one cell, unlike a multicellular organism that consists of more than one cell. Unicellular organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. Prokaryotes include bacteria and archaea. Many eukaryotes are multicellular, but the group includes the protozoa, unicellular algae, and unicellular fungi. Unicellular organisms are thought to be the oldest form of life, with early protocells possibly emerging 3.8–4 billion years ago. Although some prokaryotes live in colonies, they are not specialised into cells with differing functions. These organisms

neg: Unicellular organism live together, and each cell must carry out all life processes to survive. In contrast, even the simplest multicellular organisms have cells that depend on each other to survive. Most multicellular organisms have a unicellular life-cycle stage. Gametes, for example, are reproductive unicells for multicellular organisms. Additionally, multicellularity appears to have evolved independently many times in the history of life. Some organisms are partially unicellular, like "Dictyostelium discoideum". Additionally, unicellular organisms can be multinucleate, like Myxogastria and "Plasmodium". Primitive protocells were the precursors to today's unicellular organisms. Although the origin of life is largely still a mystery, in the currently

neg: Multicellular organism increase in size without its limitations. They can have longer lifespans as they can continue living when individual cells die. Multicellularity also permits increasing complexity by allowing differentiation of cell types within one organism. Multicellular organism Multicellular organisms are organisms that consist of more than one cell, in contrast to unicellular organisms. All species of animals, land plants and most fungi are multicellular, as are many algae, whereas a few organisms are partially uni- and partially multicellular, like slime molds and social amoebae such as the genus "Dictyostelium". Multicellular organisms arise in various ways, for example by cell division or

neg: Multicellular organism Multicellular organism Multicellular organisms are organisms that consist of more than one cell, in contrast to unicellular organisms. All species of animals, land plants and most fungi are multicellular, as are many algae, whereas a few organisms are partially uni- and partially multicellular, like slime molds and social amoebae such as the genus "Dictyostelium". Multicellular organisms arise in various ways, for example by cell division or by aggregation of many single cells. Colonial organisms are the result of many identical individuals joining together to form a colony. However, it can often be hard to separate colonial protists from true multicellular

neg: Selfing Selfing Selfing or self-fertilization is the union of male and female gametes and/or nuclei from same haploid, diploid, or polyploid organism. It is an extreme degree of inbreeding. Selfing is widespread – from unicellular organisms to the most complex hermaphroditic plants and animals (especially invertebrates). In unicellular organisms such as Protozoa, selfing can occur when two individuals (or their cell nuclei) interbreed that were produced from a previous mitotic division of the same individual. Among hermaphrodite animals there are some that regularly reproduce by self-fertilization. In others, it is a rare event; selfing in such species is more common in

neg: Biology other areas of biology, particularly those of genetics and biochemistry. Molecular biology is a study of the interactions of the various systems within a cell, including the interrelationships of DNA, RNA, and protein synthesis and how those interactions are regulated. The next larger scale, cell biology, studies the structural and physiological properties of cells, including their internal behavior, interactions with other cells, and with their environment. This is done on both the microscopic and molecular levels, for unicellular organisms such as bacteria, as well as the specialized cells of multicellular organisms such as humans. Understanding the structure and function of

neg: Lamin Lamin Nuclear lamins, also known as Class V intermediate filaments, are fibrous proteins providing structural function and transcriptional regulation in the cell nucleus. Nuclear lamins interact with membrane-associated proteins to form the nuclear lamina on the interior of the nuclear envelope. Lamins are present in all members of the kingdom Animalia (Metazoa), but are not found in unicellular organisms, plants, or fungi. Lamin proteins are involved in the disassembling and reforming of the nuclear envelope during mitosis, the positioning of nuclear pores, and programmed cell death. Mutations in lamin genes can result in laminopathies, some of which are potentially lethal

neg: Theoretical neuromorphology first elucidating the properties and function of its main unit elements, the neurons. These are complex and specialized cells. However, the improved understanding of cellular evolution achieved over the last several years has revealed that even the most sophisticated and unique properties of nerve cells represent an adaptation of basic functions observed in all eukaryotic cells, including unicellular organisms. Thus, cellular neurobiology has become an important chapter of cell biology. Studies of neurons greatly capitalize on progress in fundamental cell biology. Conversely, research on specialized features of neurons is producing major fall-outs in other areas of biology. Projects of cellular

neg: Selfing heterozygous loci is halved in each successive generation, as shown in the following table. Illustration model of the decrease in genetic variation in a population of self-fertilized organisms derived from a heterozygous individual, assuming equal fitness Selfing Selfing or self-fertilization is the union of male and female gametes and/or nuclei from same haploid, diploid, or polyploid organism. It is an extreme degree of inbreeding. Selfing is widespread – from unicellular organisms to the most complex hermaphroditic plants and animals (especially invertebrates). In unicellular organisms such as Protozoa, selfing can occur when two individuals (or their cell nuclei) interbreed that were

neg: Biological immortality a company owned by Alphabet, published a paper in the journal "eLife" which presents possible evidence that Heterocephalus glaber (Naked mole rat) do not face increased mortality risk due to aging. Many unicellular organisms age: as time passes, they divide more slowly and ultimately die. Asymmetrically dividing bacteria and yeast also age. However, symmetrically dividing bacteria and yeast can be biologically immortal under ideal growing conditions. In these conditions, when a cell splits symmetrically to produce two daughter cells, the process of cell division can restore the cell to a youthful state. However, if the parent asymmetrically buds off a

neg: Organelle footnote, which was published as a correction in the next issue of the journal, he justified his suggestion to call organs of unicellular organisms "organella" since they are only differently formed parts of one cell, in contrast to multicellular organs of multicellular organisms. While most cell biologists consider the term "organelle" to be synonymous with "cell compartment", other cell biologists choose to limit the term to include only those that contain deoxyribonucleic acid (DNA), having originated from formerly autonomous microscopic organisms acquired via endosymbiosis. Under this definition, there would only be two broad classes of organelles (i.e. those that contain

neg: Microorganism cell walls, and contain organelles such as chloroplasts in addition to the organelles in other eukaryotes. Chloroplasts produce energy from light by photosynthesis, and were also originally symbiotic bacteria. Unicellular eukaryotes consist of a single cell throughout their life cycle. This qualification is significant since most multicellular eukaryotes consist of a single cell called a zygote only at the beginning of their life cycles. Microbial eukaryotes can be either haploid or diploid, and some organisms have multiple cell nuclei. Unicellular eukaryotes usually reproduce asexually by mitosis under favorable conditions. However, under stressful conditions such as nutrient limitations and other conditions

neg: Ocelloid Ocelloid An ocelloid is a subcellular structure found in the family "Warnowiaceae" (warnowiids), which are a members of a group of unicellular organisms known as dinoflagellates. The ocelloid is analogous in structure and function to the eyes of multicellular organisms, which focus, process and detect light. The ocelloid is much more complex than the eyespot, a light-sensitive structure also found in unicellular organisms, and is in fact one of the most complex known subcellular structures. It has been described as a striking example of convergent evolution. The ocelloid was originally described in 1884. Early descriptions were met with skepticism and

neg: Dileptus Dileptus Dileptus is a genus of unicellular ciliates in the class Litostomatea. Species of "Dileptus" occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic extrusomes, with which they stun smaller organisms before consuming them. 13 species and subspecies of "Dileptus" are currently recognized. "Dileptus" species have served as model organisms, used in the study of ciliary patterns, ontogenesis, conjugation and food acquisition "Dileptus" bodies are typically narrow or cylindrical, and have a macronucleus made up of more than a hundred scattered nodules. During cell division,

neg: Cellular differentiation of asymmetric cell divisions has also been studied in green algae of the genus "Volvox", a model system for studying how unicellular organisms can evolve into multicellular organisms. In "Volvox carteri", the 16 cells in the anterior hemisphere of a 32-cell embryo divide asymmetrically, each producing one large and one small daughter cell. The size of the cell at the end of all cell divisions determines whether it becomes a specialized germ or somatic cell. Since each cell, regardless of cell type, possesses the same genome, determination of cell type must occur at the level of gene expression. While the

neg: Cell (biology) Cell (biology) The cell (from Latin "cella", meaning "small room") is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life. Cells are often called the "building blocks of life". The study of cells is called cell biology. Cells consist of cytoplasm enclosed within a membrane, which contains many biomolecules such as proteins and nucleic acids. Organisms can be classified as unicellular (consisting of a single cell; including bacteria) or multicellular (including plants and animals). While the number of cells in plants and animals varies from species to species, humans

neg: Protist Ehrenberg and Félix Dujardin. The first groups used to classify microscopic organism were the Animalcules and the Infusoria. In 1817, the German naturalist Georg August Goldfuss introduced the word "Protozoa" to refer to organisms such as ciliates and corals. After the cell theory of Schwann and Schleiden (1838–39), this group was modified in 1848 by Carl von Siebold to include only animal-like unicellular organisms, such as foraminifera and amoebae. The formal taxonomic category "Protoctista" was first proposed in the early 1860s by John Hogg, who argued that the protists should include what he saw as primitive unicellular forms of both

neg: Lamin sinus node dysfunction and atrioventricular block, and abnormally rapid heart rhythms such as ventricular tachycardia. As a result, those with Lamin A/C heart disease are often treated with pacemakers or implantable defibrillators in addition to medication. Lamin Nuclear lamins, also known as Class V intermediate filaments, are fibrous proteins providing structural function and transcriptional regulation in the cell nucleus. Nuclear lamins interact with membrane-associated proteins to form the nuclear lamina on the interior of the nuclear envelope. Lamins are present in all members of the kingdom Animalia (Metazoa), but are not found in unicellular organisms, plants, or fungi. Lamin proteins

neg: Organism consist of structural units called cells; some contain a single cell (unicellular) and others contain many units (multicellular). Multicellular organisms are able to specialize cells to perform specific functions. A group of such cells is a tissue, and in animals these occur as four basic types, namely epithelium, nervous tissue, muscle tissue, and connective tissue. Several types of tissue work together in the form of an organ to produce a particular function (such as the pumping of the blood by the heart, or as a barrier to the environment as the skin). This pattern continues to a higher level with

neg: Evolution organisms over the next few billion years. The eukaryotic cells emerged between 1.6–2.7 billion years ago. The next major change in cell structure came when bacteria were engulfed by eukaryotic cells, in a cooperative association called endosymbiosis. The engulfed bacteria and the host cell then underwent coevolution, with the bacteria evolving into either mitochondria or hydrogenosomes. Another engulfment of cyanobacterial-like organisms led to the formation of chloroplasts in algae and plants. The history of life was that of the unicellular eukaryotes, prokaryotes and archaea until about 610 million years ago when multicellular organisms began to appear in the oceans in

neg: Amoeba (genus) its food by phagocytosis, engulfing smaller organisms and particles of organic matter, or by pinocytosis, taking in dissolved nutrients through vesicles formed within the cell membrane. Food enveloped by the "Amoeba" is stored in digestive organelles called food vacuoles. "Amoeba", like other unicellular eukaryotic organisms, reproduces asexually by mitosis and cytokinesis. Sexual phenomena have not been observed in "Amoeba", although sexual exchange of genetic material is known to occur in other Amoebozoan groups. In cases where organisms are forcibly divided, the portion that retains the nucleus will often survive and form a new cell and cytoplasm, while the other portion

neg: Monera in having a different 16Ssrna. They also have a different cell wall structure. Monera Monera () (Greek - μονήρης (monḗrēs), "single", "solitary") is a kingdom that contains unicellular organisms with a prokaryotic cell organization (having no nuclear membrane), such as bacteria. They are single-celled organisms with no true nuclear membrane (prokaryotic organisms). The taxon Monera was first proposed as a phylum by Ernst Haeckel in 1866. Subsequently, the phylum was elevated to the rank of kingdom in 1925 by Édouard Chatton. The last commonly accepted mega-classification with the taxon Monera was the five-kingdom classification system established by Robert Whittaker in

neg: Kingdom (biology) classified within the animal and plant kingdoms. However, by the mid-19th century, it had become clear to many that "the existing dichotomy of the plant and animal kingdoms [had become] rapidly blurred at its boundaries and outmoded". In 1866, Ernst Haeckel proposed a third kingdom of life, the Protista, for "neutral organisms" which were neither animal nor plant. Haeckel revised the content of this kingdom a number of times before settling on a division based on whether organisms were unicellular (Protista) or multicellular (animals and plants). The development of the electron microscope revealed important distinctions between those unicellular organisms whose

neg: Juxtacrine signalling Juxtacrine signalling In biology, juxtacrine signalling (or contact-dependent signalling) is a type of cell / cell or cell / extracellular matrix signalling in multicellular organisms that requires close contact. Hence, this stands in contrast to releasing a signaling molecule by diffusion into extracellular space, or the use of long-range conduits like membrane nanotubes and cytonemes (akin to 'bridges'), or the use of extracellular vesicles like exosomes or microvesicles (akin to 'boats'). There are three types of juxtacrine signaling: Additionally, in unicellular organisms such as bacteria, juxtacrine signaling refers to interactions by membrane contact. The term "juxtacrine" was originally introduced by

neg: Contractile vacuole "Chlamydomonas". Not all species that possess a contractile vacuole are freshwater organisms; some marine, soil microorganisms and parasites also have a contractile vacuole. The contractile vacuole is predominant in species that do not have a cell wall, but there are exceptions (notably "Chlamydomonas") which do possess a cell wall. Through Evolution, the contractile vacuole has typically been lost in multicellular organisms, but it still exists in the unicellular stage of several multicellular fungi, as well as in several types of cells in sponges (amoebocytes, pinacocytes, and choanocytes). The number of contractile vacuoles per cell varies, depending on the species. "Amoeba"

neg: Marine life cellular organisation occurred in these organisms over the next few billion years. The eukaryotic cells emerged between 1.6–2.7 billion years ago. The next major change in cell structure came when bacteria were engulfed by eukaryotic cells, in a cooperative association called endosymbiosis. The engulfed bacteria and the host cell then underwent coevolution, with the bacteria evolving into either mitochondria or hydrogenosomes. Another engulfment of cyanobacterial-like organisms led to the formation of chloroplasts in algae and plants. The history of life was that of the unicellular eukaryotes, prokaryotes and archaea until about 610 million years ago when multicellular organisms began to

neg: Suspensor a transfer cell. The last of the suspensors at the end of the embryo is known as hypophysis. Hypophysis later gives rise to the radicle and root cap. During embryo development in angiosperm seeds, normal development involves asymmetrical division of the unicellular embryo, inducing polarity. The smaller terminal cell divides to become the proembryo while the larger basal cell divides laterally to form the suspensor. The suspensor is analogous to a placental mammalian's umbilical cord. Suspensor Suspensors are anatomical structures found in certain fungi and plants. In fungi, suspensors are filamentous structural formations having the function of holding a zygospore

neg: Cell (biology) within the ribosome. The new polypeptide then folds into a functional three-dimensional protein molecule. Unicellular organisms can move in order to find food or escape predators. Common mechanisms of motion include flagella and cilia. In multicellular organisms, cells can move during processes such as wound healing, the immune response and cancer metastasis. For example, in wound healing in animals, white blood cells move to the wound site to kill the microorganisms that cause infection. Cell motility involves many receptors, crosslinking, bundling, binding, adhesion, motor and other proteins. The process is divided into three steps – protrusion of the leading edge

neg: Transgenerational epigenetic inheritance Transgenerational epigenetic inheritance Transgenerational epigenetic inheritance is the transmission of information from one generation of an organism to the next (i.e., parent–child transmission) that affects the traits of offspring without alteration of the primary structure of DNA (i.e., the sequence of nucleotides)—in other words, epigenetically. The less precise term "epigenetic inheritance" may be used to describe both cell–cell and organism–organism information transfer. Although these two levels of epigenetic inheritance are equivalent in unicellular organisms, they may have distinct mechanisms and evolutionary distinctions in multicellular organisms. For some epigenetically influenced traits, the epigenetic marks can be induced by the environment and

neg: Multicellular organism first evidence of multicellularity is from cyanobacteria-like organisms that lived 3–3.5 billion years ago. To reproduce, true multicellular organisms must solve the problem of regenerating a whole organism from germ cells (i.e. sperm and egg cells), an issue that is studied in evolutionary developmental biology. Animals have evolved a considerable diversity of cell types in a multicellular body (100–150 different cell types), compared with 10–20 in plants and fungi. Loss of multicellularity occurred in some groups. Fungi are predominantly multicellular, though early diverging lineages are largely unicellular (e.g. Microsporidia) and there have been numerous reversions to unicellularity across fungi (e.g.

neg: Cell growth bridges ("Drosophila") or by internalization of nutrient storage granules (yolk granules) by endocytosis (frogs). Increases in the size of plant cells are complicated by the fact that almost all plant cells are inside of a solid cell wall. Under the influence of certain plant hormones the cell wall can be remodeled, allowing for increases in cell size that are important for the growth of some plant tissues. Most unicellular organisms are microscopic in size, but there are some giant bacteria and protozoa that are visible to the naked eye. See: Table of cell sizes —Dense populations of a giant sulfur

neg: Bacterial senescence of aging factors between daughter cells. It has long been argued that, on theoretical grounds, the preferential segregation of damage in unicellular organisms would contribute to the fitness of the overall population. The single celled eukaryotic organism, "Saccharomyces cerevisiae", retains deleterious aging factors in the mother cell leading to rejuvenation of the daughter. A well established example of bacterial aging is "Caulobacter crescentus". This bacteria begins its life as a motile swarmer cell. Once it has found a suitable substrate, the swarmer cell will differentiate into a non-motile stalked cell. The stalked cell then becomes reproductively active and gives rise

neg: Homeoviscous adaptation Homeoviscous adaptation Homeoviscous adaptation is the adaptation of the cell membrane lipid composition to keep the adequate membrane fluidity. The maintenance of proper cell membrane fluidity is of critical importance for the function and integrity of the cell, essential for the mobility and function of embedded proteins and lipids, diffusion of proteins and other molecules laterally across the membrane for signaling reactions, and proper separation of membranes during cell division. A fundamental biophysical determinant of membrane fluidity is the balance between saturated and unsaturated fatty acids. Regulating membrane fluidity is especially important in poikilothermic organisms such as bacteria, fungi, protists,

neg: Monera Monera Monera () (Greek - μονήρης (monḗrēs), "single", "solitary") is a kingdom that contains unicellular organisms with a prokaryotic cell organization (having no nuclear membrane), such as bacteria. They are single-celled organisms with no true nuclear membrane (prokaryotic organisms). The taxon Monera was first proposed as a phylum by Ernst Haeckel in 1866. Subsequently, the phylum was elevated to the rank of kingdom in 1925 by Édouard Chatton. The last commonly accepted mega-classification with the taxon Monera was the five-kingdom classification system established by Robert Whittaker in 1969. Under the three-domain system of taxonomy, introduced by Carl Woese in 1977,

neg: Manoj Kumar P. his findings are deducted from the teachings of Navajyothi Sree Karunakara Guru. Some of his Critics States that his findings belongs to metaphysics rather than Science. Manoj Kumar P. Manoj Kumar P Assistant professor is well Known for his new universal Law called Life comes from Life . He states that Life comes from Life is true in the case of humans, animals, plants, and all other Organisms including multi-cellular organisms as well as unicellular Organisms. He states that the first cell also formed from our solar system which is a Life force. He presented his research paper in 24th

neg: Manoj Kumar P. Manoj Kumar P. Manoj Kumar P Assistant professor is well Known for his new universal Law called Life comes from Life . He states that Life comes from Life is true in the case of humans, animals, plants, and all other Organisms including multi-cellular organisms as well as unicellular Organisms. He states that the first cell also formed from our solar system which is a Life force. He presented his research paper in 24th Science congress, Kerala, India where he proves that Solar System is a life force because it has got all the characteristics of a living entity. All

neg: Cyanothece Cyanothece Cyanothece is a genus of unicellular, diazotrophic, oxygenic photosynthesizing cyanobacteria. In 1976, Jiří Komárek defined the prokaryotic cyanobacteria genus "Cyanothece" as distinct from "Synechococcus" NAG 1949. Organisms in both genera share characteristics in addition to being oxygenic phototrophs. They are both unicellular, forming aggregates, but not found in mucilaginous colonies. They may have a thin mucilage layer around each cell. Both genera also divide by binary fission along an axis perpendicular to the cell’s longitudinal axis. A handful of characteristics distinguish the two genera. While "Synechococcus" species are usually cylindrical, "Cyanothece" species are normally oval and longer than 3

neg: History of botany and embryo) have a reducing division (halving of chromosomes, now known as meiosis) the field of heredity was opened up. By 1926 Thomas Morgan was able to outline a theory of the gene and its structure and function. The form and function of plastids received similar attention, the association with starch being noted at an early date. With observation of the cellular structure of all organisms and the process of cell division and continuity of genetic material, the analysis of the structure of protoplasm and the cell wall as well as that of plastids and vacuoles – what is now

neg: Mitosome Mitosome A mitosome is an organelle found in some unicellular eukaryotic organisms. The mitosome has only recently been found and named, and its function has not yet been well characterized. It was termed a "crypton" by one group, but that name is no longer in use. The mitosome has been detected only in anaerobic or microaerophilic organisms that do not have mitochondria. These organisms do not have the capability of gaining energy from oxidative phosphorylation, which is normally performed by mitochondria. The mitosome was first described in "Entamoeba histolytica," an intestinal parasite of humans. Mitosomes have also been identified in

neg: Programmed cell death because mitochondria still retain their repertoire of molecules that can trigger cell suicide. It is not clear why apoptotic machinery is maintained in the extant unicellular organisms. This process has now been evolved to happen only when programmed. to cells (such as feedback from neighbors, stress or DNA damage), mitochondria release caspase activators that trigger the cell-death-inducing biochemical cascade. As such, the cell suicide mechanism is now crucial to all of our lives. The BCR-ABL oncogene has been found to be involved in the development of cancer in humans. c-Myc is involved in the regulation of apoptosis via its role

neg: Cell theory included protozoa and other unicellular organisms, like bacteria. Though he did not have much formal education, he was able to identify the first accurate description of red blood cells and discovered bacteria after gaining interest in the sense of taste that resulted in Leeuwenhoek to observe the tongue of an ox, then leading him to study "pepper water" in 1676. He also found for the first time the sperm cells of animals and humans. Once discovering these types of cells, Leeuwenhoek saw that the fertilization process requires the sperm cell to enter the egg cell. This put an end to

neg: Bibliography of biology list of works on evolution, the change across successive generations in the heritable characteristics of biological populations. This section contains a list of works on genetics, the science of genes, heredity, and variation in living organisms. This section contains a list of publications on microbiology. Microbiology is the study of "microorganisms", which are defined as any microscopic organism that comprises either a single cell (unicellular), cell clusters or no cell at all (acellular). This section contains a list of works on molecular biology, the study of the molecular basis of biological activity. This section contains a list of works on

neg: Microbiology Microbiology Microbiology (from Greek , "mīkros", "small"; , "bios", "life"; and , "-logia") is the study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, parasitology, mycology and bacteriology. Eukaryotic microorganisms possess membrane-bound cell organelles and include fungi and protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means. Microbiologists often rely on

neg: Cell signaling activated downstream of the growth factor receptors (such as EGFR) that initiate this signal transduction pathway. Some signaling transduction pathways respond differently, depending on the amount of signaling received by the cell. For instance, the hedgehog protein activates different genes, depending on the amount of hedgehog protein present. Complex multi-component signal transduction pathways provide opportunities for feedback, signal amplification, and interactions inside one cell between multiple signals and signaling pathways. Molecular signaling can occur between different organisms, whether unicellular or multicellular. The emitting organism produces the signaling molecule, secretes it into the environment, where it diffuses, and it is sensed

neg: Cell (biology) of the cell, adhesion of the leading edge and de-adhesion at the cell body and rear, and cytoskeletal contraction to pull the cell forward. Each step is driven by physical forces generated by unique segments of the cytoskeleton. Multicellular organisms are organisms that consist of more than one cell, in contrast to single-celled organisms. In complex multicellular organisms, cells specialize into different cell types that are adapted to particular functions. In mammals, major cell types include skin cells, muscle cells, neurons, blood cells, fibroblasts, stem cells, and others. Cell types differ both in appearance and function, yet are genetically identical.

neg: Introduction to genetics it is very hard to predict. The function of genes is to provide the information needed to make molecules called proteins in cells. Cells are the smallest independent parts of organisms: the human body contains about 100 trillion cells, while very small organisms like bacteria are just one single cell. A cell is like a miniature and very complex factory that can make all the parts needed to produce a copy of itself, which happens when cells divide. There is a simple division of labor in cells—genes give instructions and proteins carry out these instructions, tasks like building a new

neg: Cellular communication (biology) Cellular communication (biology) Cellular communication is an umbrella term used in biology and more in depth in biophysics, biochemistry and biosemiotics to identify different types of communication methods between living cellulites. Some of the methods include cell signaling among others. This process allows millions of cells to communicate and work together to perform important bodily processes that are necessary for survival. Both multicellular and unicellular organisms heavily rely on cell-cell communication. Intercellular communication refers to the communication between cells. Membrane vesicle trafficking has an important role in intercellular communications in humans and animals, e.g., in synaptic transmission, hormone secretion via

neg: Metabolic theory of ecology metabolic rate and body size. The surface area in question may be skin, lungs, intestines, or, in the case of unicellular organisms, cell membranes. In general, the surface area (SA) of a three dimensional object scales with its volume (V) as "SA = cV", where c is a proportionality constant. The Dynamic Energy Budget model is currently the most promising version of these, and it predicts exponents that vary between ⅔ – 1, depending on the organism's developmental stage, basic body plan and resource density Smaller organisms tend to have higher surface area to volume ratios, causing them to gain

neg: Mallomonas Mallomonas Mallomonas is a genus comprising unicellular algal eukaryotes and characterized by their intricate cell coverings made of silica scales and bristles. The group was first named and classified by Dr. Maximilian Perty in 1852. These organisms live in freshwater and are widely distributed around the world. Some well known species include "Mallomonas caudata" and "Mallomonas splendens". "Mallomonas" is a genus of many from the phylum Ochrophyta, which describes organisms as having heterokont flagella in some part of their life history. At first, the family Mallomonadaceae was placed under class Chrysophyceae. However, after finding key biochemical and ultrastructural differences, the

neg: Paramecium caudatum conjugation, the micronuclei of each conjugant divide by meiosis and the haploid gametes pass from one cell to the other. The gametes of each organism then fuse to form diploid micronuclei. The old macronuclei are destroyed, and new ones are developed from the new micronuclei. Without the rejuvenating effects of autogamy or conjugation a "Paramecium" ages and dies. Only opposite mating types, or genetically compatible organisms, can unite in conjugation. Paramecium caudatum Paramecium caudatum is a species of unicellular organisms belonging to the genus "Paramecium" of the phylum Ciliophora. They can reach 0.25mm in length and are covered with minute

neg: Microbial genetics that live in extreme and harsh environments with low pH levels such as salt lakes, oceans, and in the gut of ruminants and humans are also known as extremophiles. In contrast, bacteria are found in various areas such as plants, animals, soil, and rocks. Fungi can be both multicellular and unicellular organisms, and are distinguished from other microbes by the way they obtain nutrients. Fungi secrete enzymes into their surroundings, to break down organic matter. Fungal genetics uses yeast, and filamentous fungi as model organisms for eukaryotic genetic research, including cell cycle regulation, chromatin structure and gene regulation. Studies of

neg: Precambrian body plans domains that are shared between metazoans and choanoflagellates. These domains play a role in cell signalling and adhesion processes in metazoans. The finding that choanoflagellates also have these genes is an incredible discovery because it was previously thought that only metazoans had genes responsible for cell-cell communication and aggregation. This suggests that these domains play a key role in the origins of multicellularity since it ties a unicellular organism (choanoflagellates) to multicellular organisms (metazoans). It shows that the components required for multicellularity were present in the common ancestor between metazoans and choanoflagellates. Neither sponges nor the placozoan Trichoplax adhaerens appear

neg: Algae Algae Algae (; singular alga ) is an informal term for a large, diverse group of photosynthetic eukaryotic organisms that are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular microalgae genera, such as "Chlorella" and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 m in length. Most are aquatic and autotrophic and lack many of the distinct cell and tissue types, such as stomata, xylem, and phloem, which are found in land plants. The largest and most complex marine algae are called seaweeds,

neg: Eukaryote Eukaryote Eukaryotes () are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes (Bacteria and Archaea). Eukaryotes belong to the domain Eukaryota or Eukarya. Their name comes from the Greek εὖ ("eu", "well" or "true") and κάρυον ("karyon", "nut" or "kernel"). Eukaryotic cells also contain other membrane-bound organelles such as mitochondria and the Golgi apparatus, and in addition, some cells of plants and algae contain chloroplasts. Unlike unicellular archaea and bacteria, eukaryotes may also be multicellular and include organisms consisting of many cell types forming different kinds of tissue. Animals and plants are the most familiar eukaryotes. Eukaryotes

neg: Carbon-neutral fuel into gasoline, jet fuel or other hydrocarbons, but that requires additional energy and more complex production facilities. Methanol is slightly more corrosive than traditional fuels, requiring automobile modifications on the order of USD $100 each to use it. In 2016, a method using carbon spikes, copper nanoparticles and nitrogen that converts carbon dioxide to ethanol was developed. Microalgae are aquatic organisms living in a large and diverse group. They are unicellular organisms that do not have complex cell structures like plants. However, they are still photo autotrophic, able to use solar energy to convert chemical forms via photosynthesis. They are

neg: Cell division entire new organism is created. On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings. Mitotic cell division enables sexually reproducing organisms to develop from the one-celled zygote, which itself was produced by meiotic cell division from gametes. After growth, cell division by mitosis allows for continual construction and repair of the organism. The human body experiences about 10 quadrillion cell divisions in a lifetime. The primary concern of cell division is the maintenance of the original cell's genome. Before division can occur, the genomic information that is stored in

neg: Mitochondrial DNA organisms (e.g. in some species of Cnidaria) the mtDNA is found as linearly organized DNA. Most of these linear mtDNAs possess telomerase-independent telomeres (i.e. the ends of the linear DNA) with different modes of replication, which have made them interesting objects of research, as many of these unicellular organisms with linear mtDNA are known pathogens. For human mitochondrial DNA (and probably for that of metazoans in general), 100–10,000 separate copies of mtDNA are usually present per somatic cell (egg and sperm cells are exceptions). In mammals, each double-stranded circular mtDNA molecule consists of 15,000–17,000 base pairs. The two strands of

neg: Natural computing as diverse as self-replication, the functioning of the brain, Darwinian evolution, group behavior, the immune system, the defining properties of life forms, cell membranes, and morphogenesis. Besides traditional electronic hardware, these computational paradigms can be implemented on alternative physical media such as biomolecules (DNA, RNA), or trapped-ion quantum computing devices. Dually, one can view processes occurring in nature as information processing. Such processes include self-assembly, developmental processes, gene regulation networks, protein–protein interaction networks, biological transport (active transport, passive transport) networks, and gene assembly in unicellular organisms. Efforts to understand biological systems also include engineering of semi-synthetic organisms, and understanding the

neg: Archaeplastida captured cyanobacteria. In glaucophytes, perhaps the most primitive members of the group, the chloroplast is called a "cyanelle" and shares several features with cyanobacteria, including a peptidoglycan cell wall, that are not retained in other members of the group. The resemblance of cyanelles to cyanobacteria supports the endosymbiotic theory. The cells of most archaeplastidans have walls, commonly but not always made of cellulose. The Archaeplastida vary widely in the degree of their cell organization, from isolated cells to filaments to colonies to multi-celled organisms. The earliest were unicellular, and many groups remain so today. Multicellularity evolved separately in several groups,

neg: Excretion Excretion Excretion is a process by which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys and skin. This is in contrast with secretion, where the substance may have specific tasks after leaving the cell. Excretion is an essential process in all forms of life. For example, in mammals urine is expelled through the urethra, which is part of the excretory system. In unicellular organisms, waste products are discharged directly through the surface of the cell. During life activities such as cellular respiration, several chemical reactions take place in the body.

neg: State switching changes in the diploid genome of the cancer cell or other unicellular organisms, how information to activate such an internal genetic switch is transmitted to the germline for stable inheritance in metazoans reproducing sexually remains an important and intriguing question. Notwithstanding the molecular mechanisms however, an equally important question that needs to be considered here is the evolutionary timescale. A key point in Darwinian evolution is that it works very slowly, over millions of years of geological time, through the gradual, incremental acquisition of small differences. Then how can a cancer cell evolve in such a short time? Perhaps, as

neg: Signal transduction and survival; in the absence of growth factor, apoptosis ensues. Such requirements for extracellular stimulation are necessary for controlling cell behavior in unicellular and multicellular organisms; signal transduction pathways are perceived to be so central to biological processes that a large number of diseases are attributed to their disregulation. Three basic signals determine cellular growth: The combination of these signals are integrated in an altered cytoplasmic machinery which leads to altered cell behaviour. Following are some major signaling pathways, demonstrating how ligands binding to their receptors can affect second messengers and eventually result in altered cellular responses. The earliest notion

neg: Evolution of the eye nearly all major animal groups, and are common among unicellular organisms, including euglena. The euglena's eyespot, called a "stigma", is located at its anterior end. It is a small splotch of red pigment which shades a collection of light sensitive crystals. Together with the leading flagellum, the eyespot allows the organism to move in response to light, often toward the light to assist in photosynthesis, and to predict day and night, the primary function of circadian rhythms. Visual pigments are located in the brains of more complex organisms, and are thought to have a role in synchronising spawning with lunar

neg: C15orf52 protein. There is a homologous domain found in Coiled Coil Domain Containing Protein 9 (CCDC9) that is paralogous to the C15orf52 protein from amino acid 9 to 55 of CCDC9. This domain is found in primates to mollusks. This CCDC9 domain is not found in any unicellular organisms or multicellular organisms more distant than mollusks. Orthologs of the C15orf52 protein were traced back to cartilaginous fishes. None were found in any multicellular organisms more distant than cartilaginous fishes or unicellular organisms. A comparison of the corrected distances of C15orf52 with the rapidly mutating Fibrinogen Alpha protein and the slowly mutating

neg: Precambrian body plans impressions, which resemble trilobite walking trails For the majority of Earth’s history life has been unicellular. However, unicellular organisms had the ingredients in them for multicellularity to arise. Despite having the ingredients for multicellularity, organisms were restricted due to the lack of hospitable environmental conditions. The rise of oxygen (The Great Oxygenation Event) led organisms to be able to develop more complex body plans. In order for multicellularity to have occurred, organisms must have been capable of cellular communication, aggregation, and specialized functions. The transition to multicellularity that began the evolution of animals from protozoa is one of the most

neg: Mitochondrion emphasizes the integration of the mitochondria, the product of an endosymbiotic event, into diverse cellular processes. Mitochondria (and related structures) are found in all eukaryotes (except one—the Oxymonad "Monocercomonoides" sp.). Although commonly depicted as bean-like structures they form a highly dynamic network in the majority of cells where they constantly undergo fission and fusion. The population of all the mitochondria of a given cell constitutes the chondriome. Mitochondria vary in number and location according to cell type. A single mitochondrion is often found in unicellular organisms. Conversely, the chondriome size of human liver cells is large, with about 1000–2000 mitochondria

neg: Reticulate evolution is a special form of symbiosis whereby an organism lives inside another, different organism. Symbiogenesis is thought to be very important in the origin and evolution of eukaryotes. Eukaryotic organelles, such as mitochondria, have been theorized to have been originated from cell-invaded bacteria living inside another cell. Lateral gene transfer, or horizontal gene transfer, is the movement of genetic material between unicellular and/or multicellular organisms without a parent-offspring relationship. The horizontal transfer of genes results in new genes, which could give new functions to the recipient and thus could drive evolution. In the neo-Darwinian paradigm, one of the assumed definition

neg: Cloning has been transfected, to grow. Additionally, the cloning vectors may contain colour selection markers, which provide blue/white screening (alpha-factor complementation) on X-gal medium. Nevertheless, these selection steps do not absolutely guarantee that the DNA insert is present in the cells obtained. Further investigation of the resulting colonies must be required to confirm that cloning was successful. This may be accomplished by means of PCR, restriction fragment analysis and/or DNA sequencing. Cloning a cell means to derive a population of cells from a single cell. In the case of unicellular organisms such as bacteria and yeast, this process is remarkably simple

neg: CGMP-dependent protein kinase CGMP-dependent protein kinase cGMP-dependent protein kinase or Protein Kinase G (PKG) is a serine/threonine-specific protein kinase that is activated by cGMP. It phosphorylates a number of biologically important targets and is implicated in the regulation of smooth muscle relaxation, platelet function, sperm metabolism, cell division, and nucleic acid synthesis. PKG are serine/threonine kinases that are present in a variety of eukaryotes ranging from the unicellular organism "Paramecium" to humans. Two PKG genes, coding for PKG type I (PKG-I) and type II (PKG-II), have been identified in mammals. The N-terminus of PKG-I is encoded by two alternatively spliced exons that specify

neg: Allorecognition by such cheaters takes two major forms. First, a consistent feature of the multicellular life cycle is the interposition of a unicellular phase, even among organisms whose major mode of propagation may be via many-celled vegetative propagules. This unicellular phase usually takes the form of a sexually produced zygote. Passage through a unicellular bottleneck assures that each representative of the next generation of organisms represents a distinct clone. Some offspring will carry a large number of deleterious mutations and will die off, while other offspring will carry few. In this manner, the organism bypasses "Muller's ratchet," the process by which

neg: Biology considered to be the basic unit in many pathological processes. In addition, the phenomenon of energy flow occurs in cells in processes that are part of the function known as metabolism. Finally, cells contain hereditary information (DNA), which is passed from cell to cell during cell division. Research into the origin of life, abiogenesis, amounts to an attempt to discover the origin of the first cells. A central organizing concept in biology is that life changes and develops through evolution, and that all life-forms known have a common origin. The theory of evolution postulates that all organisms on the Earth,

neg: Gravitational biology colonization of planets larger than the Earth is ever to take place. Recent experiments have proven that alterations in metabolism, immune cell function, cell division, and cell attachment all occur in the hypogravity of space. For example, after a matter of days in microgravity (< 10 "g"), human immune cells were unable to differentiate into mature cells. One of the large implications of this is that if certain cells cannot differentiate in space, organisms may not be able to reproduce successfully after exposure to zero gravity. Scientists believe that the stress associated with space flight is responsible for the inability

neg: Cell lineage Cell lineage Cell lineage denotes the developmental history of a tissue or organ from the fertilized embryo. Cell lineage can be studied by marking a cell (with fluorescent molecules or other traceable markers) and following its progeny after cell division. Some organisms as "C. elegans" have a predetermined pattern of cell progeny and the adult male will always consist of 1031 cells, this is because cell division in "C. elegans" is genetically determined and known as eutely. This causes the cell lineage and cell fate to be highly correlated. Other organisms, such as humans, have variable lineages and somatic cell

neg: Microorganism microorganisms caused the diseases tuberculosis, cholera and anthrax. Microorganisms include all unicellular organisms and so are extremely diverse. Of the three domains of life identified by Carl Woese, all of the Archaea and Bacteria are microorganisms. These were previously grouped together in the two domain system as Prokaryotes, the other being the eukaryotes. The third domain Eukaryota includes all multicellular organisms and many unicellular protists and protozoans. Some protists are related to animals and some to green plants. Many of the multicellular organisms are microscopic, namely micro-animals, some fungi and some algae, but these are not discussed here. They live

neg: Cell lineage these approaches facilitate reconstruction of lineage trees. These approaches promise to provide more comprehensive analysis of lineage relationships in model organisms. Cell lineage Cell lineage denotes the developmental history of a tissue or organ from the fertilized embryo. Cell lineage can be studied by marking a cell (with fluorescent molecules or other traceable markers) and following its progeny after cell division. Some organisms as "C. elegans" have a predetermined pattern of cell progeny and the adult male will always consist of 1031 cells, this is because cell division in "C. elegans" is genetically determined and known as eutely. This causes

neg: Reticulamoeba for both swimming and gliding and once they become stationary they resorb the flagella and eject their reticulopodia to return to the amoeboid stage (Bass et al., 2012). Species of "Reticulamoeba" differ in their method of cell division. The cells undergo cell division in one of two ways, either by binary fission or by unequal binary fission (Bass et al., 2012). Reticulamoeba Introduction "Reticulamoeba" is a genus of Rhizaria. It is a relatively large unicellular protist and is commonly known for its thin reticulopodia radiating outwards from the cell (Bass et al., 2012). "Reticulamoeba" are strictly benthic protists that use

neg: Cell adhesion processes regulated by cell adhesion include cell migration and tissue development in multicellular organisms. Alterations in cell adhesion can disrupt important cellular processes and lead to a variety of diseases, including cancer and arthritis. Cell adhesion is also essential for infectious organisms, such as bacteria or viruses, to cause diseases. CAMs are classified into four major families: integrins, immunoglobulin (Ig) superfamily, cadherins, and selectins. Each of these adhesion molecules has a different function and recognizes different ligands. Cadherins and immunoglobulins are homophilic CAMs, as they directly bind to the same type of CAMs on another cell, while integrins and selectins

neg: Harold M. Weintraub While at FHCRC, Weintraub continued and extended his prior studies of chromatin structure and function. Another of his contributions was developing the technique of using antisense RNA to create specific mutant phenotypes in vertebrate organisms. Perhaps the work for which Weintraub is best known was his laboratory's discovery and characterization of "myoD", the first master regulatory gene. When expressed, the myoD gene produces a protein referred to as MyoD (or MyoD1), which can bind certain DNA sequences, stop cell division, and elicit an entire program of muscle cell differentiation. In a series of sequential experiments, Weintraub and his students showed

neg: Michael Melkonian Einstein College of Medicine of Yeshiva University (Bronx, N.Y.). From 1986–1988 he was a Heisenberg Fellow of the German Research Foundation (DFG). Since 2001 Melkonian is also Director of the Culture Collection of Algae at the University of Cologne (CCAC). Melkonian has research interests that range from cell biology, Melkonian studied the structure, function and development of the flagellar apparatus in algae and co-discovered several centrosomal proteins novel for eukaryotes (e.g. centrin, SF-assemblin). He further provided evidence that flagellar development in unicellular eukaryotes extends over more than one cell cycle generating flagella with different functions in the same cell. Through

neg: Acclimatization encountered, and fewer dictionaries enter it. In order to maintain performance across a range of environmental conditions, there are several strategies organisms use to acclimate. In response to changes in temperature, organisms can change the biochemistry of cell membranes making them more fluid in cold temperatures and less fluid in warm temperatures by increasing the number of membrane proteins. Organisms may also express specific proteins called heat shock proteins that may act as molecular chaperons and help the cell maintain function under periods of extreme stress. It has been shown, that organisms which are acclimated to high or low temperatures

neg: Actinophryid Actinophryid The actinophryids are an order of heliozoa. They are the most common heliozoa in fresh water and can also be found in marine and soil habitats. Actinophryids are unicellular and roughly spherical in shape, with many axopodia that radiate outward from the cell body. Axopodia are a type of pseudopodia that are supported by hundreds of microtubules arranged in a needle-like internal structure. These axopods adhere to passing prey and assist with cell movement, as well as playing a part in cell division and cell fusion. Actinophryids are largely aquatic protozoa with a spherical cell body and many needle-like

neg: Chemokinesis which provides data about migration of identical cells, whereas, in Protozoa (e.g., Tetrahymena), techniques based on measurement of opalescence were also developed. Chemokinesis Chemokinesis is chemically prompted kinesis, a motile response of unicellular prokaryotic or eukaryotic organisms to chemicals that cause the cell to make some kind of change in their migratory/swimming behaviour. Changes involve an increase or decrease of speed, alterations of amplitude or frequency of motile character, or direction of migration. However, in contrast to chemotaxis, chemokinesis has a random, non-vectorial moiety, in general. Due to the random character, techniques dedicated to evaluate chemokinesis are partly different from

neg: Growth medium the genera: "Cytophaga", "Flavobacterium", "Bacillus", "Pseudomonas", and "Alcaligenes"). Bacteria grown in liquid cultures often form colloidal suspensions. The difference between growth media used for cell culture and those used for microbiological culture is that cells derived from whole organisms and grown in culture often cannot grow without the addition of, for instance, hormones or growth factors which usually occur "in vivo". In the case of animal cells, this difficulty is often addressed by the addition of blood serum or a synthetic serum replacement to the medium. In the case of microorganisms, no such limitations exist, as they are often unicellular

neg: Golenkinia Golenkinia Golenkinia is a genus of green algae first described in 1894 by Robert Chodat. The genus is named for the Russian phycologist Mikhail Iljitsch Golenkin. "Golenkinia" species live in fresh water and are found around the world. Members of "Golenkinia" are spherical unicellular organisms with numerous radiating spines. Their cell walls are notably thick, which distinguishes them from members of the genus "Golenkinopsis". They contain a single walled cup-shaped chloroplast, which in turn contains a pyrenoid in its base. The pyrenoid is typically sheathed in starch. Species of "Golenkinia" are typically solitary and do not form colonies or coenobia

neg: Biology is localized in the cell nucleus, or with small amounts in mitochondria and chloroplasts. In prokaryotes, the DNA is held within an irregularly shaped body in the cytoplasm called the nucleoid. The genetic information in a genome is held within genes, and the complete assemblage of this information in an organism is called its genotype. Homeostasis is the ability of an open system to regulate its internal environment to maintain stable conditions by means of multiple dynamic equilibrium adjustments that are controlled by interrelated regulation mechanisms. All living organisms, whether unicellular or multicellular, exhibit homeostasis. To maintain dynamic equilibrium and

neg: Eyespot apparatus cytoskeleton. This asymmetric positioning of the eyespot in the cell is essential for proper phototaxis. The most critical eyespot proteins are the photoreceptor proteins that sense light. The photoreceptors found in unicellular organisms fall into two main groups: flavoproteins and retinylidene proteins (rhodopsins). Flavoproteins are characterized by containing flavin molecules as chromophores, whereas retinylidene proteins contain retinal. The photoreceptor protein in "Euglena" is likely a flavoprotein. In contrast, "Chlamydomonas" phototaxis is mediated by archaeal-type rhodopsins. Besides photoreceptor proteins, eyespots contain a large number of structural, metabolic and signaling proteins. The eyespot proteome of "Chlamydomonas" cells consists of roughly 200 different

neg: Synechococcus the prokaryotic autotrophic picoplankton in the temperate to tropical oceans. The genus was first described in 1979, and was originally defined to include "small unicellular cyanobacteria with ovoid to cylindrical cells that reproduce by binary traverse fission in a single plane and lack sheaths". This definition of the genus "Synechococcus" contained organisms of considerable genetic diversity and was later subdivided into subgroups based on the presence of the accessory pigment phycoerythrin. The marine forms of "Synechococcus" are coccoid cells between 0.6 and 1.6 µm in size. They are Gram-negative cells with highly structured cell walls that may contain projections on

neg: Apicomplexa Apicomplexa The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of plastid called an apicoplast, and an apical complex structure. The organelle is an adaptation that the apicomplexan applies in penetration of a host cell. The Apicomplexa are unicellular and spore-forming. All species are obligate endoparasites of animals, except "Nephromyces", a symbiont in marine animals, originally classified as a chytrid fungus. Motile structures such as flagella or pseudopods are present only in certain gamete stages. The Apicomplexa are a diverse group that includes organisms

neg: Pinnularia Pinnularia Pinnularia is a fresh water alga more specifically a type of Bacillariophyta (diatom). "Pinnularia" is a predominantly fresh-water alga, usually found in ponds and moist soil. They can also be found in springs, estuaries, sediments, and oceans. Members of this genus are most commonly found in of water, at . "Pinnularia" are elongated elliptical unicellular organisms. Their cell walls are composed chiefly of pectic substances on a rigid silica framework. Their walls are composed of two halves called thecae (or less formally, valves.) These halves overlap like a Petri dish and its cover. The margins of the two thecae

neg: Mallomonas part of the Paleogene Period, occurring about 56 to 33.9 million years ago. Studies with this fossil taxon would suggest that parts of its morphology have been retained up to the present. To date, the genus "Mallomonas" has 223 species. A list of well-known species is provided in the table below. Mallomonas Mallomonas is a genus comprising unicellular algal eukaryotes and characterized by their intricate cell coverings made of silica scales and bristles. The group was first named and classified by Dr. Maximilian Perty in 1852. These organisms live in freshwater and are widely distributed around the world. Some well

neg: Amoeboid movement can also swim, using a similar mechanism as for crawling. Another unicellular form of movement shown in Euglena is known as metaboly. Amoeboid movement Amoeboid movement is the most common mode of locomotion in eukaryotic cells. It is a crawling-like type of movement accomplished by protrusion of cytoplasm of the cell involving the formation of pseudopodia ("false feet") and posterior uropods. One or more pseudopodia may be produced at a time depending on the organism, but all amoeboid movement is characterized by the movement of organisms with an amorphous form that possess no set motility structures. Movement occurs when the