central

Vacuole

...les in protists 2 Vacuoles in plant cells: the central vacuole 3 Vacuoles in budding yeast cells ...water protozoa . Vacuoles in plant cells: the central vacuole Most mature plant cells have a central vacuole , which often takes up more than 80% of t...

Thermoregulation

...s of heat are themselves probably regulated by the central nervous system, there being a thermogenic centresi...ted. This diminished metabolism tells first on the central nervous system, especially the brain and those parts concerned in consciousness. Both heart-beat and...

Synapse

...es form the circuits in which the neurons of the central nervous system interconnect. They are thus crucial to the biological computations that underlie perception and thought. They also provide the means through which the nervous system connects to and controls the other systems of the body. The word "s...

Species

...ter thousands of years of use, the concept remains central to biology and a host of related fields, and yet also remains at times ill-defined and controversial. Implications of assignment of species status The naming of a particular species should be regarded as a hypothesis about the evolutionary rel...

Rudolf Steiner

... to continue for thousands more. Apart from his central book on social questions, Toward Social Renewal , there are at least two others available in English: World Economy (14 lectures from 1922) and The Social Future (revised edition 1972). A few aspects of Steiner's way of thinking Accordin...

Punctuated equilibrium

...n summarized by Gould as follows: "Large, stable central populations exert a strong homogenizing influence [on the gene pool]. New and favorable mutations are diluted by the sheer bulk of the population through which they must spread....But [in] small, peripherally isolated groups [that] are cut off from ...

Prion

...ntroversial, because it seemed to contradict the " central dogma of modern biology ", which asserts that all ...now widely accepted. Rather than contradicting the central role of DNA, however, the prion hypothesis suggests a special and possibly exceptional case in which...

Nucleosome

... DNA. Structure The histones make up the central core particle of the nucleosome. The DNA is wrap...hat the 30 nm fiber is arranged into loops along a central protein scaffold to form transcriptionally active euchromatin . Further compaction leads to transcr...

Neurotransmitter

...fying the local membrane voltage potential. In the central nervous system, combined input from several synaps...A, glycine) are used very generally throughout the central nervous system, others are only used in certain brain regions by particular classes of nerve cells. ...

Neuron

...nvey information from tissues and organs into the central nervous system . Efferent neurons transmit signals from the central nervous system to the effector cells . Interneurons connect neurons within the central nervous...

Neural plate

...forms the neural tube which then forms the CNS ( central nervous system ), comprised by the spinal cord and the brain . Masses of tissue called the neural crest separate from the neural tube and form the cord's sensory neurons ....

Nervous system

... of vertebrate animals are often divided into a central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord . The PNS consists of all other nerves and neurons that do not lie within the CNS. The large majority of what are commonly called ner...

Nephron

...ecting duct . The collecting ducts empty into the central cavity of the kidney, the renal pelvis , which connects to the ureter . Each human kidney has about a million nephrons. The basic function of the nephron is to regulate water and soluble substances (especially ions ) in the body by filtering...

Muscle

...s and provide feedback sensory information to the central nervous system . Skeletal muscle is arranged in discrete groups, examples of which include the biceps brachii . It is connected by tendons to processes of the skeleton . In contrast, smooth muscle occurs at various scales in almost every organ...

Molecular biology

...n and translation of the genetic material . The central dogma of molecular biology where genetic material is transcribed into RNA and then translated into protein, despite being an oversimplified picture of molecular biology, still provides a good starting point for understanding the field. This picture,...

Lynn Margulis

... her theory of symbiogenesis , which challenges a central tenet of neodarwinism . She argues that inherited variation, significant in evolution, does not come mainly from random mutations. Rather new tissues, organs, and even new species evolve primarily through the long-lasting intimacy of strangers. The ...

Liver

...r based on blood supply and biliary drainage. The central area where the common bile duct , portal vein , and hepatic artery enter the liver is the hilum or "porta hepatis". The duct, vein, and artery divide into left and right branches, and the portions of the liver supplied by these branches constitu...

Citric acid cycle

...ebs cycle ) is a series of chemical reactions of central importance in all living cells that utilize oxygen as part of cellular respiration . In these aerobic organisms , the citric acid cycle is a metabolic pathway that forms part of the break down of carbohydrates , fats and proteins into c...

Kary Mullis

... invented the polymerase chain reaction (PCR), a central technique in molecular biology which allows the amplification of specified DNA sequences. He was awarded the Nobel Prize in Chemistry and the Japan Prize for this work in 1993 . Mullis was born in North Carolina, and grew up in Columbia, So...

Insulin

...cytes ). The former are important because of their central role in movement, breathing, circulation, etc, and...y manifests itself in impaired functioning of the central nervous system – dizzness, speech problems, even loss of consciousness, are common. This phen...

Immunology

..., including their function and interaction, is the central science of immunology. The immune system has been divided into innate immune system , and acquired or adaptive immune system , the latter of which is further divided into humoral and cellular components . The mainstay of classical immunology has ...

Human

...dy The physical appearance of the human body is central to culture and art . In every human culture, pe...d language , Origins of language .) Language is central to the communication between humans. The Hebrew word for "animal" ( behemah ) means "mute", defi...

Golgi apparatus

...t them within vesicles . Thus, it functions as a central delivery system for the cell. Most of the transport vesicles that leave the endoplasmic reticulum (ER), specifically rough ER, are transported to the Golgi apparatus, where they are modified, sorted and shipped towards their final destination. T...

Glucose

...on of protein and in lipid metabolism. As the central nervous system does not metabolise lipids, it is more dependent on glucose than other tissues. Glucose is absorbed into the bloodstream through the intestinal wall . Some of this glucose goes directly to fuel brain cells , while the rest makes ...

Genetics

... that genes code for proteins ; see the original central dogma of genetics 1944 Oswald Theodore Avery ...d Temin showed using RNA viruses that Watson's central dogma is not always true 1970 Restriction enzymes were discovered in studies of a bacterium, H...

Gene

...NA . Together, these discoveries established the central dogma of molecular biology , which states that proteins are transcribed from RNA which is translated from DNA. This dogma has since been shown to have exceptions, such as reverse transcription in retroviruses . See also Genetics , Gene e...

Flagellum

...pairs of microtubules doublets surrounding two central single microtubules. The so-called "9+2"" structure is the characteritics of the core of the eukaryotic flugellum called an axoneme . At the base of a eukaryotic flagellum is a basal body or kinetosome, which is the microtubule organizing ce...

Eukaryote

...r plants, most of a cell's volume is taken up by a central vacuole or tonoplast, which maintains its osmotic pressure. Mitochondria and plastids Mitochondria are organelles found in nearly all eukaryotes. They are surrounded by double membranes, the inner of which is folded into invaginations called...

Evolution

...e the rare variants have a higher fitness. The central role of natural selection in evolutionary theory has given rise to a strong connection between that field and the study of ecology . Mutations that are not affected by natural selection are called neutral mutations . Their frequency in the populat...

Eugenics

...sed, with eugenicists for the first time playing a central role in the Congressional debate, as expert advisers on the threat of "inferior stock" from Eastern and Southern Europe. This reduced the number of immigrants from abroad to fifteen percent of that of previous years, to control the proportion of "unf...

Ebola

...the CDC .The nucleocapsid structure consists of a central channel, 20-30 nm in diameter, surrounded by helically wound capsid with a diameter of 40-50 nm and an interval of 5 nm. 7 nm glycoprotein spikes that are 10 nm apart from each other are present within the outer envelope of the virus, which is deri...

DNA

...ublished in 1953 . Watson and Crick proposed the central dogma of molecular biology in 1957 , describing the process whereby proteins are produced from nucleic DNA. First isolation of DNA Working in the 19th century , biochemists initially isolated DNA and RNA (mixed together) from cell nuclei. They...

Diabetes mellitus

...blood, deficiency of insulin or its action plays a central role in all forms of diabetes. Most of the carbohydrates in food are rapidly digested to glucose , the principal sugar in blood. Insulin is produced by beta cells in the pancreas in response to rising levels of glucose in the blood, as oc...

Citric acid cycle

...ebs cycle ) is a series of chemical reactions of central importance in all living cells that utilize oxygen as part of cellular respiration . In these aerobic organisms , the citric acid cycle is a metabolic pathway that forms part of the break down of carbohydrates , fats and proteins into c...

Cilium

...and other associated proteins. Motile cilia have a central core with two additional microtubule singlets and ...tructure. The non-motile cilia do not have the two central microtubule singlets and do not have dyneins. This configuration of axoneme is referred as a "9 + 0...

Cancer

...nt malignancy, followed by the leukemias and the central nervous system cancers. Female infants and male in...y occurring to least: neuroblastoma , leukemia , central nervous system, retinoblastoma , Wilms' tumor , germ cell, soft tissue sarcomas , hepatic, lymph...

Brain

...same term can also be used for the invertebrate central nervous system . In most animals, the brain is loc...bes behind each eye for visual processing and a central brain with three divisions. The cephalopod brain has a central group of lobes known as circumesopha...

Bone

... are tubular in structure (e.g. the tibia ). The central shaft of a long bone is called the diaphysis , and has a hollow middle - the medullar cavity - filled with bone marrow. Surrounding the medullar cavity is a thin layer of cancellous bone that also contains marrow. The extremities of the bone are ...

Barbiturate

Barbiturates are drugs that acts as central nervous system (CNS) depressants , and by virtue of this they produce a wide spectrum of effects, from mild sedation to anesthesia . Some also are used as anticonvulsants . Barbiturates are derivatives of barbituric acid. Contents showTo...

Blastula

...ce. A blastula has around 128 cells, with a large central cavity called the blastocoel . Also called blastosphere ....

Biology

...y, cells and the genetic code 1.2 Evolution: the central principle of biology 1.3 Diversity: the variety ...es and include similar genes . Evolution: the central principle of biology Main article: Evolution One of the central, organizing concepts in biolo...

Axon

...ns and oligodendrocytes insulating those of the central nervous system . Along myelinated nerve fibers, gaps in the sheath known as nodes of Ranvier occur at evenly spaced intervals, enabling an especially rapid mode of electrical impulse propagation called saltation . The axons of some neurons bran...

Archaea

...enetic transcription and translation - the two central processes in molecular biology - do not show the typical bacterial features, but are extremely similar to those of eukaryotes . For instance, archaean translation uses eukaryotic initiation and elongation factors, and their transcription involves...

Apoptosis

...trinsic pathways have in common the activation of central effectors of apoptosis , a group of cysteine proteases called caspases , which carry out the cleaving of both structural and functional elements of the cell, resulting in the previously described morphological changes. Biochemical execution ...

Andrew Huxley

...he activity of an organism to be coordinated by a central nervous system . Hodgkin and Huxley shared the prize that year with John Carew Eccles , who was cited for research on synapses . Hodgkin and Huxley's findings led the pair to hypothesize ion channels , which were confirmed only decades later. The...

Alternative splicing

...d pre-mRNA. (This does not necessarily negate the central dogma of genetics which is about the flow of information from genes to proteins). Since the ways of regulation are inherited, the interpretation of a mutation may be changed. It has been proposed that for eukaryotes it was a very important st...