Moldova Xmol-'do-voN officially Republic of Moldova Country, northeastern Balkan Peninsula, southeastern Europe. It is bordered by Ukraine and Romania. Area: 13,068 sq mi (33,845 sq km). Population (2005 est.): 4,206,000. Capitaclass="underline" Chi$inau. Nearly half the population is Moldovan; there also are large numbers of Russians and Ukrainians, espe¬ cially in the Transnistria region, east of the Dniester River. Languages: Romanian (officially designated as Moldovan), Russian, Ukrainian. Reli¬ gions: Christianity (mostly Eastern Orthodox, also other Christians); also Islam. Currency: leu. Most of Moldova is a fertile region lying between the Dniester and Prut rivers; the northern and central regions of the coun¬ try are forested. The economy is based on agriculture; the major farm products are grapes, winter wheat, com, and dairy products. Industry is centred on food processing. Moldova is a republic with one legislative body; its head of state is the president, and the head of government is the prime minister. The area of present-day Moldova consists of that part of the historic principality of Moldavia lying east of the Prut River (part of Romania before 1940) and, adjoining it on the south, the region of Bessa-
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mole ► molecule I 1277
1991 Moldavia declared independence from the Soviet Union. It adopted the Romanian spelling of Moldova, having earlier legitimized use of the Roman rather than the Cyrillic alpha-
Examples of common molding styles.
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bet. Moldova was admitted to the UN in 1992. In 2000 it abandoned its semipresidential form of government to become a parliamentary repub¬ lic.
mole or mol Vmol\ Standard unit for measuring everyday quantities of such minute entities as atoms or molecules. For any substance, the num¬ ber of atoms or molecules in a mole is Avogadro's number (6.02 x 10 23 ) of particles. Defined exactly, it is the amount of pure substance contain¬ ing the same number of chemical units that there are in exactly 12 g of carbon- 12. For each substance, a mole is its atomic weight, molecular weight, or formula weight in grams. The number of moles of a solute in a litre of solution is its molarity (M); the number of moles of solute in 1,000 g of solvent is its molality (m). The two measures differ slightly and have different uses. See also stoichiometry.
mole Any burrowing, often blind insectivore in the family Talpidae (including 42 species of true moles) or Chrysochloridae (18 species of golden moles). Most species have short legs and tail, a pointed head, vel¬ vety grayish fur, no external ears, and a strong odour. They range from 3.5 to 8 in. (9 to 20 cm) long. The forelimbs are rotated outward like oars and have broad or pointed claws on the toes. Moles are active day and night, digging surface tunnels in search of earthworms, grubs, and other invertebrates and excavating deep (10 ft [3 m]), vented burrows (mole¬ hills) for occupancy. The star-nosed mole (Condylura cristata) of north¬ eastern North America has 22 pink, tentacle-like touch organs radiating from its muzzle.
mole Pigmented flat or fleshy skin mark, made up mostly of cells that produce melanin, which gives moles their light to dark brown or black colour and, in the dermis, a bluish cast. Thicker moles also contain nerve elements and connective tissue. Moles often begin in childhood, usually as flat spots between the dermis and epidermis. Those that remain there are more likely to become malignant. Most move into the dermis and become slightly raised. In children, moles may undergo changes resem¬ bling cancer but are benign. Malignant melanoma can begin in moles but almost never before puberty. During pregnancy, moles may enlarge and new ones may appear. Moles sometimes disappear with age. The term nevus refers to a congenital skin mark, whereas a mole may develop after birth. Epidermal nevi are usually the same colour as the surrounding skin.
molecular biology Field of science concerned with the chemical structures and processes of biological phenomena at the molecular level. Having developed out of the related fields of biochemistry, genetics, and biophysics, the discipline is particularly concerned with the study of pro¬ teins, nucleic acids, and enzymes. In the early 1950s, growing knowledge of the structure of proteins enabled the structure of DNA to be described. The discovery in the 1970s of certain types of enzymes that can cut and recombine segments of DNA (see recombination) in the chromosomes of certain bacteria made recombinant-DNA technology possible. Molecular biologists use that technology to isolate and modify specific genes (see GENETIC ENGINEERING).
molecular weight Mass of a molecule of a substance, based on 12 as the atomic weight of carbon- 12. It is calculated in practice by sum¬ ming the atomic weights of the atoms making up the substance’s molecu¬ lar formula. The molecular weight of a hydrogen molecule (chemical formula H 2 ) is 2 (after rounding off); for many complex organic molecules (e.g., proteins, polymers) it may be in the millions.
molecule Smallest identifiable unit into which a pure substance can be divided and retain its composition and chemical properties. Division into still smaller parts, eventually atoms, involves destroying the bonding that holds the molecule together. For noble gases, the molecule is a single atom; all other substances have two (diatomic) or more (polyatomic) atoms in a molecule. The atoms are the same in elements, such as hydrogen (H 2 ), and different in compounds, such as glucose (C 6 H 12 0 6 ). Atoms always combine into molecules in fixed proportions. Molecules of different sub¬ stances can have the same constituent atoms, either in different propor¬ tions, as in carbon monoxide (CO) and carbon dioxide (C0 2 ), or bonded in different ways (see isomer). The covalent bonds in molecules give them their shapes and most of their properties. (The concept of molecules has no significance in solids with ionic bonds.) Analysis with modern tech¬ niques and computers can determine and display the size, shape, and con¬ figuration of molecules, the positions of their nuclei and electron clouds, the lengths and angles of their bonds, and other details. Electron micros¬ copy can even produce images of individual molecules and atoms. See also molecular weight. See illustration on following page.
L_
M
N
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1278 I Moley ► Molotov
L_
N
CHO
H
OH
CH 3 ch 3 ch 3
bond-line formula of vitamin A
HO-H
H-OH
Kekule structure of benzene
H
. ■ H I
Lewis
structures of H : C : H or H-C-H
methane
Several methods of representing a molecule's structure. In Lewis structures, element symbols represent atoms, and dots represent electrons surrounding them. A pair of shared electrons (covalent bond) may also be shown as a single dash. The ball- and-stick model better illustrates the spatial arrangement of the atoms. For aromatic compounds, the Kekule structure is common, in which each bond is represented by a dash, carbon atoms are implied where two or more lines meet, and hydrogen atoms are usually omitted. Bond-line formulas, similar to the Kekule structure, are often used for complex nonaromatic organic compounds. Sugars are often drawn as Fischer projections, in which the carbon "backbone" is drawn as a straight verti¬ cal line, with carbon atoms implied where horizontal lines intersect the vertical one.
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Moley, Raymond (Charles) (b. Sept. 27, 1886, Berea, Ohio, U.S.—d. Feb. 18, 1975, Phoenix, Ariz.) U.S. educator and political adviser. He taught political science at Columbia University from 1923 to 1954. In the 1920s he prepared studies of criminal justice in a number of cities for New York Gov. Franklin D. Roosevelt. When Roosevelt was pre¬ paring for his 1932 presidential campaign, Moley formed the Brain Trust to advise him on national issues. Moley wrote many of Roosevelt’s cam¬ paign speeches and coined the term New Deal. From 1937 to 1968 he was a contributing editor of Newsweek magazine.