lower

Turgor

...into the cell (since the concentration of water is lower inside the cell than outside), causing it to expand. The cell wall of a plant cell restricts the expansion, causing the cell to press against the wall. The resulting pressure is called turgor. The osmotic pressure π of a dilute solution can be ...

Thomas Malthus

...s only for the working and poor classes. Thus, the lower social classes took a great deal of responsibility for societal ills, according to his theory. Essentially what this resulted in was the promotion of legislation which degenerated the conditions of the poor in England. The influence of Malthus's the...

Thermoregulation

... of that of the surrounding air, whereas among the lower animals there is much variation of body temperatur...the animal back again, for the time being, on to a lower plane of evolution. Ectotherms Main article: Ectotherm Even though fishes are ectotherms so...

Stoma

.... Dicotyledons usually have more stomata on the lower epidermis than the upper epidermis. As these leav...s floating leaves, there will be no stomata on the lower epidermis as it can absorb gases directly from water through cuticle . If it is submerged leaf, no...

Species

... can be defined as being of a taxon hierarchically lower than a species. In zoology only the subspecies is used, while in botany the variety , subvariety , and form are used as well. The isolation species concept in more detail In general, for large, complex, organisms that reproduce sexually...

Skin

...elasticity. Skin also receives less blood flow and lower gland activity. In medicine , the branch concerned with the skin is called dermatology . The skin is subject to constant attack from without, and so can be afflicted by numerous ailments, such as: Tumors : Benign tumors of the skin: Squamous...

Blood plasma

... oxygen . (Oxygen transport capacity of plasma is lower compared to that of the hemoglobin in the red blood cells ; it may increase under hyperbaric conditions.) It is the storage and transport medium of clotting factors and its protein content is necessary to maintain the oncotic pressure of the b...

RNA virus

...edit out mistakes. DNA viruses have considerably lower mutation rates. See also retroviruses . Although RNA usually mutates rapidly, recent work found that the SARS virus and related RNA viruses contain a gene that mutates very slowly. The gene in question has a complex three-dimensional structure ...

Plasmolysis

...n area of high water concentration to an area of lower water concentration outside the cell. It is unlike...ll originally contains a dilute solution with much lower osmotic pressure than that of the calcium nitrate solution on the other side of the membrane. The v...

Photon

...photon (a gamma ray ; a photon of the immediately lower energy range is denoted X , an X-ray ). Properties All electromagnetic radiation, from radio waves to gamma rays, is quantised as photons: that is, the smallest amount of electromagnetic radiation that can exist is one photon whatever its wa...

Polymerase chain reaction

...nnealing temperature usually is -5C the calculated lower Tm. However it should be chosen empirically for individual conditions. Inner self-complementary hairpins of >4 and of dimers >8 should be avoided. 3' terminus is extremely case sensitive - it must not be complementary to any region of the...

Passive transport

...igh concentration of that material to an area with lower concentration. The difference of concentration between the two areas is often termed as the concentration gradient , and diffusion will continue until this gradient has been eliminated. Since diffusion moves material from area of higher concentratio...

Parthenogenesis

... male . Parthenogenesis occurs naturally in some lower plants (called agamospermy ), invertebrates (e.g. water fleas , aphids ) and some vertebrates (e.g. lizards , salamanders , some fish , and even turkeys ). Parthenogenetic populations are typically all-female.As with all types of asexua...

Osmoregulation

...er wants to move in. Hypotonic is a solution with lower solute concentration (lower osmotic pressure) than another thus water wants to move out of it. Isotonic is solution with the same solute concentration (same osmotic pressure) as another; no net movement of water. Forms of osmoregulation Two maj...

Origin of life

...controversial. Other less reducing gases produce a lower yield and variety and the presence of free oxygen prevents any organomolecules from forming. The experiment showed that many of the basic organic molecules that form the building blocks of modern life can be formed spontaneously. Simple organic mol...

Nucleotide

...to standard four-letter codes. The first letter is lower case and indicates whether the nucleotide in question is a ribonucleotide (r) or deoxyribonucleotide (d). The second letter indicates the nucleobase: G: Guanine A: Adenine T: Thymine C: Cytosine U: Uracil not present in DNA, but...

Magnetic resonance imaging

...g the operation. Such open bore magnets are often lower field magnets, typically in the 0.2 tesla range, which decreases their sensitivity but also decreases the Radio Frequency power potentially absorbed by the patient during a protracted operation. Radiation Therapy Simulation Because of MRI's sup...

Lichen

...face resembles the upper surface and is called the lower cortex , consisting of densely packed fungal hyphae. The lower cortex often bears structures, such as rhizinae or a tomentum , serving to attach the thallus to t...

Leaf

...sues: An epidermis that covers the upper and lower surfaces An interior chlorenchyma called the ...show dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. The epid...

Kidney

... to L3, and the right kidney usually lies slightly lower than the left in order to accommodate the liver . The upper parts of the kidneys are partially protected by the eleventh and twelfth ribs , and each whole kidney is surrounded by two layers of fat (the perirenal fat and the pararenal fat) which he...

Isozyme

...-phosphate . Its different regulatory features and lower affinity for glucose (compared to other hexokinases), allows it to serve different functions in cells of specific organs, such as control of insulin release by the beta cells of the pancreas , or initiation of glycogen synthesis by liver cel...

Insulin

...cells slows or stops. If blood glucose levels drop lower than this, especially to dangerously low levels, release of hyperglycemic hormones (most prominently glucagon from Islet alpha cells) forces release of glucose into the blood from cellular stores. The release of insulin is strongly inhibited by the s...

Immune system

...ize a broad spectrum of pathogens. Plants and many lower animals do not possess an adaptive immune system and instead rely on innate immunity. The study of the innate immune system has recently flourished. Earlier studies of innate immunity utilized model organisms that lack adaptive immunity such as the ...

Human

..., over the earth and all other creatures, a little lower than the angels (see Great Chain of Being ), and are alone in possessing a conscience. In Judaism and Christianity, humanity is seen as unique among creatures in being made in the image of God , and intended for a relationship of love and obedien...

Homeostasis

...uds and thus increase the atmospheric albedo and lower the temperature of the atmosphere. Biological homeostasis Homeostasis is one of the fundamental characteristics of living things. It is the maintenance of the internal environment within tolerable limits. The internal environment of a living ...

Heterozygote

... indicated with a capital and the recessive with a lower case character. The colour of Mendel's peas are often indicated as PP for the dominant homozygote pink flower and pp for the recessive homozygote white flower. When these are crossed, the F1 or second generation will be heterozygote for the c...

Fermentation

...the brewing process. Doing the latter rest at the lower end of the range produces more low-order sugars wh...table by the yeast . This in turn creates a beer lower in body and higher in alcohol . While a rest closer to the higher end of the range creates more hi...

Fitness landscape

...(points from which all paths are downhill, i.e. to lower fitness) and valleys (regions from which most paths lead uphill). A fitness landscape with many local peaks surrounded by deep valleys is called rugged. If all genotypes have the same replication rate, on the other hand, a fitness landscape is said t...

Extinction

...g them. It can also occur over longer periods at lower toxicity levels by affecting life span, reproductive capacity, or competitiveness. DDT played such a role in killing off bald eagles and other birds by thinning the egg shell walls of affected birds, thus lowering the survivability of offsprin...

Evolutionary tree

...s from earlier ideas of life as a progression from lower to higher forms. Although such views are discredited now, the imagery is too well established to be readily lost. The terminology originates with Linnaean taxonomy : living things are classified as belonging to domain, kingdom, phylum, class, order...

Enzyme

...o a rope attached to a hanging weight. In order to lower the total net energy, the system will drive the co...ng or enabling a different reaction pathway with a lower activation energy , making it easier for the reaction to occur. The overall rate of enzyme mediate...

Ebola

...dan (EBO–S) . The outbreak in Sudan showed a lower fatality rate — 50% — compared to the 90% mortality rate of the Zare strain. In 1990 , a third, similar virus was identified in Reston , Virginia among monkeys imported from the Philippines , and was named Ebola–Reston . Thi...

Escherichia coli

...of the main species of bacteria that live in the lower intestines of warm-blooded animals (including birds and mammals ) and are necessary for the proper digestion of food. Its presence in groundwater is a common indicator of fecal contamination. ("Enteric" is the adjective that describes organis...

DNA

...NA. These viruses presumably also benefit from the lower cost of replicating one strand versus two. The history of DNA research James Watson in the Cavendish Laboratory at the University of Cambridge The discovery that DNA was the carrier of genetic information was a process which re...

Diffusion

...r air molecules (e.g. oxygen , nitrogen ) have lower mobilities and thus diffuse more slowly through the balloon wall. There is a concentration gradient in the balloon wall because the balloon was filled up with helium, and thus there is plenty of helium on the inside, but there is relatively little h...

Dialysis

...id is drained directly from the upper bag into the lower bag. This clears the line of air and other impurities. The drain line is then clamped off and the twist valve on the catheter end is opened. This permits fluid to enter the peritoneum. Filling the abdomen with fresh fluid takes about fifteen minutes,...

Diabetes mellitus

...and potassium) Insulin to reverse the ketosis and lower the glucose Careful monitoring to detect and trea...glycemia. Adequate control of diabetes leads to a lower risk of the complications of uncontrolled diabetes which include kidney failure (requiring dialysis ...

Cloning

.... Brave New World : the population is grown.The lower castes are cloned from a single egg (Bokanofskyfied ). External links Cloning in Focus , an accessible and comprehensive look at cloning research from the University of Utah's Genetic Science Learning Center Click and Clone . Try it yourse...

Chromatography

...nent of the mobile phase is increased. RP-HPLC has lower resolution than GC. Gel permeation chromatography Gel permeation chromatography , also known as size exclusion chromatography or Sephadex gel chromatography, separates molecules on basis of size. Smaller molecules enter a porous media and take...

Cancer

...er supplements compared with those receiving much lower amounts of supplemental wheat bran fiber. On the ... a 5-alpha reductase inhibitor , has been shown to lower the risk of prostate cancer. Other examples of drugs that show promise for chemoprevention include ...

Anatomy

...nimals are concerned; but only those parts of the lower animals which are of interest in explaining human body structure are here dealt with. The articles have a twofold purpose; first, to give enough details of structure to make the articles on physiology, surgery, medicine and pathology intelligible; a...

Amine

...rong acids like HI, HBr, or HCl does not lead to a lower grade amine and an alkylhalide, hence the nitrogen-group is not a preferred leaving group. The only kind of succesful elimination is the elimination of an alkyl-group from quaternary ammonium salts , the so called Hofmann Elimination ...

Albumin

...smaller animals (for example rats ) function at a lower blood pressure , they need less oncotic pressure to balance this, and thus need less albumin to maintain proper fluid distribution. Functions of albumin: Maintains oncotic pressure Transports thyroid hormones Transports other hormones, par...

Active transport

...also posses a calcium ATPase, which can operate at lower intracellular concentrations of calcium and sets the normal or resting concentration of this important second messenger . But the ATPase exports calcium ions more slowly: only 30 per second versus 2000 per second by the exchanger. The exchanger come...

Activation energy

... A substance that modifies the transition state to lower the activation energy is termed a catalyst ; a biological catalyst is termed an enzyme . Fig 1. The enthalpy profile of a reaction between two hydrogen peroxide molecules to form water and oxygen. The Transition State is the point ...