deoxyribonucleic acid


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deoxyribonucleic acid

 (DNA) [de-ok″sĭ-ri″bo-nu-kle´ik]
a nucleic acid of complex molecular structure occurring in cell nuclei as the basic structure of the genes. DNA is present in all body cells of every species, including unicellular organisms and DNA viruses. The structure of DNA was first described in 1953 by J. D. Watson and F. H. C. Crick.

DNA molecules are linear polymers of small molecules called nucleotides, each of which consists of one molecule of the five-carbon sugar deoxyribose bonded to a phosphate group and to one of four heterocyclic nitrogenous compounds referred to as bases. A single strand of DNA is made by linking the nucleotides together in a chain with bonds between the sugar and phosphate groups of adjacent nucleotides. It thus consists of a backbone of alternating sugar and phosphate groups with a base attached to each sugar as a side chain. The four bases are two purines, adenine (A) and guanine (G), and two pyrimidines, cytosine (C) and thymine (T). Single-stranded DNA can be synthesized with any specified sequence of bases, but in living cells the base sequence has a meaning: it specifies the amino acid sequence of all of the polypeptides and proteins made by the cell. And since all of the enzymes that catalyze biochemical reactions are proteins, the DNA contains the specifications for all of the biochemistry and structure of the cell.

The chemical basis of the genetic code lies in the ability of the bases to form hydrogen bonds with each other. Unlike the covalent bonds holding together the atoms of a single strand of DNA, hydrogen bonds are weak and easily broken and reformed. Hydrogen bonding is governed by the base pairing rule: A always bonds with T, and C always bonds with G. A and T (or C and G) are called complementary bases. The genetic information is read and preserved by the matching up of complementary bases.

In cells, the DNA is double-stranded. The configuration of the DNA molecule resembles a ladder in which the sides are the sugar-phosphate backbones, which are antiparallel (they run in opposite directions), and the rungs are hydrogen-bonded complementary bases; thus, the entire sequence along the two strands is complementary. This whole structure is twisted so that the two strands form a double helix. Once before each cell division, a group of proteins splits the two strands apart, and as complementary nucleotides bond to the bases of each strand they are joined to form a new strand. This process is called replication. It results in the exact duplication of the DNA molecule, because each strand serves as a template (pattern) for the synthesis of its complementary strand. When the cell divides, one copy goes to each daughter cell. Thus, the genetic information is passed on from generation to generation without change except for rare mutations, which result from copying errors or incorrectly repaired breaks in the DNA molecule that change the base sequence.

The reading of the genetic code involves two processes: transcription and translation. In transcription, a length of DNA is used as a template to make a complementary strand of messenger RNA (mRNA). RNA (ribonucleic acid) is a nucleic acid like DNA. The only differences are that the sugar, ribose, has an extra oxygen atom, and the pyrimidine base, uracil (U), which also pairs with adenine, replaces thymine. In translation, the mRNA molecule is read by a structure called a ribosome, which produces the polypeptide specified by the mRNA message.

The genetic code is a triplet code. Every triplet of bases along the strand specifies a single amino acid. There are 64 possible triplets (codons) that can be formed from the four bases. Each one specifies that one of 20 different amino acids be inserted in a growing polypeptide chain or marks either the start or the end of a chain.

Two other types of RNA are involved in translation. Ribosomal RNA (rRNA) forms a large part of the ribosome. Transfer RNA (tRNA) is the means by which codons are matched with amino acids. tRNAs are small molecules with several self-complementary sections so that they fold up into a compact structure owing to bonding between complementary bases. One end of the molecule is a three-base anticodon, which bonds to its complementary codon on mRNA molecules. The other end is recognized by a specific enzyme that attaches the correct amino acid to it. During translation, the ribosome proceeds along the mRNA molecule and, as each codon is matched by a specific tRNA, the amino acid it carries is transferred to the growing polypeptide chain, and the process is repeated until the “stop” codon is reached. Like the mRNA molecules, rRNA and tRNA molecules are formed on DNA templates; the genetic material contains the information not only for polypeptide sequences but also for rRNA and tRNA sequences.

There is an enormous amount of information stored in the DNA of a cell. The 48 chromosomes of a human cell contain a total length of about 6 billion base pairs of DNA. This is enough to code for the thousands of enzymes and structural proteins in the cell. DNA is the molecule that directs all of the activities of living cells, including its own reproduction and perpetuation in generation after generation.
The basic building blocks of DNA.
 The helical, double-stranded structure of the gene. The outside strands are composed of phosphoric acid and the sugar deoxyribose. The internal molecules that connect the two strands of the helix are purine and pyrimidine bases; these determine the code of the gene.

de·ox·y·ri·bo·nu·cle·ic ac·id (DNA),

(dē-oks'ē-rī'bō-nū'klē'ik as'id),
The type of nucleic acid containing deoxyribose as the sugar component and found principally in the nuclei (chromatin, chromosomes) and mitochondria of animal and plant cells, usually loosely bound to protein (hence the term deoxyribonucleoprotein); considered to be the autoreproducing component of chromosomes and of many viruses, and the repository of hereditary characteristics. Its linear macromolecular chain consists of deoxyribose molecules esterified with phosphate groups between the 3'- and 5'-hydroxyl groups; linked to this structure are the purines adenine (A) and guanine (G) and the pyrimidines cytosine (C) and thymine (T). DNA may be open ended or circular, single or double stranded. Many forms are known, the most commonly described of which is double stranded, wherein the pyrimidines and purines cross-link through hydrogen bonding in the schema A-T and C-G, bringing two antiparallel strands into a double helix. Chromosomes are composed of double-stranded DNA; mitochondrial DNA is circular.

deoxyribonucleic acid

/de·oxy·ri·bo·nu·cle·ic ac·id/ (DNA) (-ri″bo-noo-kle´ik) the nucleic acid in which the sugar is deoxyribose; composed also of phosphoric acid and the bases adenine, guanine, cytosine, and thymine. It constitutes the primary genetic material of all cellular organisms and the DNA viruses and occurs predominantly in the nucleus, usually as a double helix (q.v.), where it serves as a template for synthesis of ribonucleic acid (transcription).
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The DNA double helix. A, Diagrammatic model of the helical structure, showing its dimensions, the major and minor grooves, the periodicity of the bases, and the antiparallel orientation of the backbone chains (represented by ribbons). The base pairs (represented by rods) are perpendicular to the axis and lie stacked one on another. B, The chemical structure of the backbone and bases of DNA, showing the sugar phosphate linkages of the backbone and the hydrogen bonding between the base pairs. There are two hydrogen bonds between adenine and thymine, and three between cytosine and guanine.

deoxyribonucleic acid

(dē-ŏk′sē-rī′bō-no͞o-klē′ĭk, -klā′-, -nyo͞o-)
n.
DNA.

deoxyribonucleic acid (DNA)

[dē·ok′sirī′bōno̅o̅klē′ik]
a large, double-stranded, helical molecule that is the carrier of genetic information. In eukaryotic cells, it is found principally in the chromosomes of the nucleus. DNA is composed of four kinds of serially repeating nucleotide bases: adenine, cytosine, guanine, and thymine. Genetic information is coded in the sequence of the nucleotides. Also called desoxyribonucleic acid. See also nucleic acid, ribonucleic acid.
enlarge picture
Genetic code and base sequencing of DNA

deoxyribonucleic acid

See DNA.

de·ox·y·ri·bo·nu·cle·ic ac·id

(DNA) (dē-oks'ē-rī'bō-nū-klē'ik as'id)
The type of nucleic acid containing deoxyribose as the sugar component; found principally in the nuclei (chromatin, chromosomes) and mitochondria of animal and plant cells, usually loosely bound to protein (hence the term deoxyribonucleoprotein); considered to be the autoreproducing component of chromosomes and of many viruses, and the repository of hereditary characteristics. Its linear macromolecular chain consists of deoxyribose molecules esterified with phosphate groups between the 3'- and 5'-hydroxyl groups; linked to this structure are the purines adenine (A) and guanine (G) and the pyrimidines cytosine (C) and thymine (T). DNA may be open ended or circular, single or double stranded. Many forms are known, the most commonly described of which is double-stranded, wherein the pyrimidines and purines cross-link through hydrogen bonding in the schema A-T and C-G, bringing two antiparallel strands into a double helix. Chromosomes are composed of double-stranded DNA; mitochondrial DNA is circular.

acid

(as'id) [L. acidus, sour]
1. Any substance that liberates hydrogen ions (protons) in solution; a hydrogen ion donor. An acid reacts with a metal to form a salt, neutralizes bases, and turns litmus paper red.
2. A substance that can accept a pair of electrons; a Lewis acid. See: alkali; base; indicator; Lewis acid; pH
3. A sour substance.
4. Slang term for lysergic acid diethylamide (LSD).

acetic acid

C2H4O2, the acid that gives the sour taste to vinegar. It is also used as a reagent. Glacial (highly purified) acetic acid contains at least 99.5% acetic acid by weight.
CAS # 64-19-7

acetoacetic acid

C4H6O3, a ketone body formed when fats are incompletely oxidized. It was formerly called acetylacetic acid. Synonym: diacetic acid; diacetic acid
CAS # 541-50-4

acetylacetic acid

See: acetoacetic acid

acetylsalicylic acid

Abbreviation: ASA
Aspirin (1).

acrylic acid

C3H4O2, a colorless corrosive acid used in making acrylic polymers and resins.
CAS # 79-10-7

adenylic acid

Adenosine monophosphate.

alpha-hydroxy acid

Abbreviation: AHA
Any of a class of water-soluble acids derived from fruit or milk, having a hydroxyl moiety in the first position in the molecule. AHAs are used in chemical peels and other skin care products to remove the outer layer of the epidermis. This chemical exfoliation is promoted for its cosmetic effects on wrinkled or sun-damaged skin.

alpha-linolenic acid

C18H30O2, an omega-3 fatty acid derived from plants, esp. seeds (canola oil, flaxseed, walnuts and pumpkins) and from some fish (salmon and mackerel).
CAS # 463-40-1

alpha-lipoic acid

C8H14O2S2, a natural coenzyme and antioxidant, used for short-term treatment of peripheral neuropathies.
CAS # 1200-22-2

amino acid

See: amino acid

aminoacetic acid

Glycine.

aminobenzoic acid

Para-aminobenzoic acid.

aminocaproic acid

C6H13NO2, a hemostatic drug. It is a specific antidote for an overdose of a fibrinolytic agent.
CAS # 60-32-2

aminoglutaric acid

Glutamic acid.

aminosalicylic acid

Para-aminosalicylic acid.

aminosuccinic acid

Aspartic acid.

arachidonic acid

C20H32O2, an omega-6 fatty acid formed by the action of enzymes on phospholipids in cell membranes. The acid is found in many foods. It is metabolized primarily by the cyclo-oxygenase or 5-lipoxygenase pathways to produce prostaglandins and leukotrienes, which are important mediators of inflammation. Corticosteroids inhibit formation of arachidonic acid from phospholipids when cell membranes are damaged. Nonsteroidal anti-inflammatory agents such as salicylates, indomethacin, and ibuprofen inhibit the synthesis of prostaglandins and leukotrienes.
CAS # 506-32-1

argininosuccinic acid

C10H18N4O6, a compound intermediate in the synthesis of arginine, formed from citrulline and aspartic acid.
CAS # 2387-71-5

aristolochic acid

C17H11NO7, an acid derived from Aristolochia, a genus of flowering plants, and used as an herbal remedy. It is promoted as an aphrodisiac, a weight loss agent, and an anticonvulsant.
CAS # 313-67-7

CAUTION!

The acid is a known carcinogen, and its use has been associated with and may cause end-stage renal disease and cancers of the urinary tract that may occur many years after usage has stopped.

ascorbic acid

Vitamin C.

aspartic acid

C4H7NO4, a nonessential amino acid that is a product of pancreatic digestion. Synonym: aminosuccinic acid
CAS # 617-45-8

barbituric acid

C4H4N2O3, a crystalline acid from which phenobarbital and other barbiturates are derived.
CAS # 67-52-7

benzoic acid

C7H6O2, a white crystalline acid having a slight odor. It is used in keratolytic ointments and in food preservation. Saccharin is a derivative of this acid.
CAS # 65-85-0

bile acid

Any of the complex acids that occur as salts in bile, e.g., cholic, glycocholic, and taurocholic acids. They give bile its foamy character, are important in the digestion of fats in the intestine, and are reabsorbed from the intestine to be used again by the liver. See: enterohepatic circulation

binary acid

An acid containing hydrogen and one other element.

boric acid

H3BO3, a white crystalline acid that in water forms a very weak acid solution poisonous to plants and animals. It is soluble in water, alcohol, and glycerin. See: boric acid poisoning
CAS # 10043-35-3

CAUTION!

Boric acid is toxic and should be used only rarely. It is particularly dangerous because it can be accidentally swallowed by children or used in food because of its resemblance to sugar.

butyric acid

C4H8O2, a viscous fatty acid with a rancid odor, derived from butter but rare in most fats. It is used in disinfectants, emulsifying agents, and pharmaceuticals.
CAS # 107-92-6

carbolic acid

Phenol (1).

carbonic acid

H2CO3, an acid formed when carbon dioxide is dissolved in water.
CAS # 463-79-6

carboxylic acid

Any acid containing the carboxyl group –COOH. The simplest examples are formic and acetic acids.

cell-free fetal nucleic acid

Free fetal nucleic acid.

cholic acid

C24H40O5, a bile acid formed in the liver by hydrolysis of other bile acids. It is formed from the breakdown of cholesterol and helps digest consumed fats.
CAS # 81-25-4

cinnamic acid

C9H8O2, an insoluble white powder derived from cinnamon. It is used as a flavoring agent in cooking and in the preparation of perfumes and medicines.
CAS # 140-10-3

citric acid

C6H8O7, an acid found naturally in citrus fruits or prepared synthetically. It acts as a sequestrant, helping to preserve food quality.
CAS # 77-92-9

conjugated linoleic acid

Abbreviation: CLA
Any of the isomers of linoleic acid effective against cancer, obesity, diabetes, and atheromata in laboratory rodents. CLAs have not been shown to have similar beneficial effects in humans.

cysteic acid

C3H7NO5S, an acid produced by the oxidation of cysteine. Further oxidation produces taurine.
CAS # 498-40-8

deoxycholic acid

C24H40O4, a crystalline acid found in bile.
CAS # 83-44-3

deoxyribonucleic acid

, desoxyribonucleic acid See: DNA

diacetic acid

Acetoacetic acid.

2,4-dichlorophenoxyacetic acid

2,4-D.

p-dichlorosulfamoyl benzoicacid

Halazone.

4,8-dihydroxyquinaldic acid

Xanthurenic acid.

docosahexaenoic acid

, docosahexanoic Abbreviation: DHA
C22H32O2, an omega-3 fatty acid found in the oils of cold-water fish and in algae. DHA plays a role in the development of nerve cell membranes and is required for the normal growth and development of the infant brain. Lack of DHA has been linked to growing numbers of people suffering from depression.
CAS # 6217-54-5

domoic acid

C15H20NO6, a toxin that resembles glutamate, the main excitatory amino acid of the brain. When ingested, it may cause continuous seizures.
CAS # 14277-97-5

eicosapentaenoic acid

Abbreviation: EPA
C20H30O2, an omega-3 fatty acid found in fish oils, containing 20 carbons and five double bonds.
CAS # 10417-94-4

endogenous uric acid

Uric acid derived from purines undergoing metabolism from the nucleic acid of body tissues.

essential fatty acid

Abbreviation: EFA
A fatty acid (alpha-linoleic and linoleic) that is essential for health and must be present in the diet because it cannot be synthesized in the body. See: digestion

ethylenediaminetetraacetic acid

Abbreviation: EDTA
C10H16N2O8, a chelating agent that, in its calcium or sodium salts, is used to remove metallic ions such as lead and cadmium from the body and as a food preservative. See: chelation
CAS # 60-00-4

exogenous uric acid

Uric acid derived from purines from food made up of free purines and nucleic acids.
See: urate; uraturia

fatty acid

Any of numerous monobasic acids with the general formula CnH2n+1-COOH (an alkyl radical attached to a carboxyl group).

Fatty acids are insoluble in water. This insolubility would prevent their being absorbed from the intestines, but the action of bile salts on the fatty acids enable thems to be absorbed. Fatty acids include acetic, butyric, capric, caproic, caprylic, formic, lauric, myristic, palmitic, and stearic acids. Unsaturated fatty acids have one or more double or triple bonds in the carbon chain. They include those of the oleic series (oleic, tiglic, hypogeic, and palmitoleic) and the linoleic or linolic series (linoleic, linolenic, clupanodonic, arachidonic, hydrocarpic, and chaulmoogric). See: fat

folic acid

C19H19N7O6, a water-soluble B complex vitamin needed for DNA synthesis and amino acid metabolism. It is present in green leafy vegetables, beans, and yeast. It is used to treat megaloblastic and macrocytic anemias and to prevent neural tube defects (NTDs) and cardiovascular disease in adults. The U.S. Public Health Service recommends that all women of childbearing age who may become or are pregnant should consume 0.8 mg of folic acid daily to reduce their risk of having a child affected with spina bifida or other NTDs. See: neural tube defect Synonym: folate; vitamin B9
CAS # 59-30-3

CAUTION!

Folic acid should not be used to treat pernicious anemia (a vitamin B12 deficiency) because it does not protect patients against the development of changes in the central nervous system that accompany this type of anemia.

folinic acid

C20H23N7O7, the active form of folic acid. It is used to counteract the effects of folic acid antagonists and to treat folic acid deficiency anemia.
CAS # 1492-18-8

formic acid

HCOOH, the first and strongest member of the monobasic fatty acid series. It occurs naturally in certain animal secretions, e.g., the sting of insects such as bees and ants, and in muscle, but it is also prepared synthetically.
CAS # 64-18-6

formiminoglutamic acid

C6N2O4H10, an intermediate product in the metabolism of histidine.
CAS # 816-90-0

free fatty acid

Abbreviation: FFA
The form in which a fatty acid leaves the cell to be transported for use in another part of the body. FFAs are not esterified and may be unbound (not bound to protein). In the plasma, the nonesterified fatty acids released immediately combine with albumin to form bound free fatty acids.

free fetal nucleic acid

Abbreviation: ffNA
Fetal RNA or DNA in blood or body fluids. It is used to determine the sex of the fetus (as in pregnancies in which X-linked inherited diseases are a concern) or to identify other genetically transmitted illnesses, e.g., trisomies. Synonym: cell-free fetal nucleic acid

fumaric acid

C4H4O4, one of the organic acids in the Krebs cycle. It is used as a substitute for tartaric acid in beverages and baking powders.
CAS # 110-17-8

fuming nitric acid

Concentrated nitric acid (more than 86% nitric acid) that emits toxic fumes that cause choking if inhaled.
See: fumes

gadolinium-diethylenetriamine pentaacetic acid

Abbreviation: Gd-DTPA
A radiographic contrast agent, used in magnetic resonance imaging to enhance the appearance of blood vessels.

CAUTION!

Contrast agents containing gadolinium should not be given to patients with diminished renal function.
CAS # 86050-77-3

gallic acid

C6H2(OH)3COOH, a colorless crystalline acid. It occurs naturally as an excrescence on the twigs of trees, esp. oaks, as a reaction to the deposition of gall wasp eggs. It is used as a skin astringent and in the manufacture of writing inks and dyes.
CAS # 149-91-7

gamma-aminobutyric acid

Abbreviation: GABA
C4H9NO2, the principal inhibitory neurotransmitter of the brain.
CAS # 56-12-2

gamma-linolenic acid

Abbreviation: GLA
C18H30O2, an essential fatty acid promoted by alternative medicine practitioners as a treatment for skin and inflammatory disorders, cystic breast disease, and hyperlipidemia.
CAS # 506-26-3

glucuronic acid

CHO(CHOH)4COOH, an oxidation product of glucose that is present in the urine. Toxic products (salicylic acid, menthol, phenol) that have entered the body through the intestinal tract are detoxified in the liver by conjugation with glucuronic acid.
CAS # 6556-12-3

glutamic acid

HOOC·(CH2)2·CH(NH2)·COOH, an amino acid formed in protein hydrolysis and an excitatory neurotransmitter in the central nervous system. Synonym: aminoglutaric acid
CAS # 617-65-2

glyceric acid

CH2OH·CHOH·COOH, an intermediate product of the oxidation of fats.
CAS # 473-81-4

glycocholic acid

C26H43NO6, a bile acid that hydrolizes to glycine and cholic acid.
CAS # 475-31-0

glycolic acid

C2H4O3, an alpha-hydroxy acid derivative used to remove the outer layer of skin to rejuvenate its appearance.
CAS # 79-14-1

glyoxylic acid

C2H2O3, an acid produced by the action of glycine oxidase on glycine or sarcosine.
CAS # 298-12-4

hippuric acid

C6H5CONHCH2COOH, an acid formed and excreted by the kidneys. It is formed from the combination of benzoic acid and glycine. The synthesis takes place in the liver and, to a limited extent, in the kidneys.
CAS # 495-69-2

guanidoacetic acid

An acid formed in the liver, kidney, and other tissues. It is metabolized to form creatine.

hexafluorosilicic acid

Silicofluoride.

homogentisic acid

C8H8O4, an intermediate product of tyrosine catabolism. It is found in the urine in alkaptonuria. Synonym: alkapton
CAS # 451-13-8

hyaluronic acid

Abbreviation: HA
(C14H21NO11)n, an acid mucopolysaccharide found in the extracellular matrix of connective tissue that acts as a binding and protective agent. It is found in synovial fluid and in the vitreous and aqueous humors of the eye. Patients with osteoarthritis have elevated serum levels of HA. Synonym: hyaluronan
CAS # 9004-61-9

hydriodic acid

HI, an acid used in solution in various forms of chemical analyses. Synonym: hydrogen iodide
CAS # 10034-85-2

hydrochloric acid

HCl, an inorganic acid normally present in gastric juice. It destroys fermenting bacteria that might cause intestinal tract disturbances.

CAS# 7647-01-0

hydrocyanic acid

HCN, a colorless, extremely poisonous, highly volatile acid that occurs naturally in plants but is also produced synthetically. It acts by preventing cellular respiration. Hydrocyanic acid is used in electroplating, fumigation, and in producing dyes, pigments, synthetic fibers, and plastic. Exposure of humans to 200 to 500 parts of hydrocyanic acid per 1,000,000 parts of air for 30 min is fatal. Synonym: hydrogen cyanide
CAS # 74-90-8

hydrofluoric acid

HF, a corrosive solution of hydrogen fluoride in water. It can be used in dentistry to etch composites and porcelain surfaces and is used industrially to etch glass. See: hydrogen fluoride

CAUTION!

Exposure to the skin and aerodigestive tract causes severe burns with local necrosis and systemic manifestations resulting from disordered calcium and potassium metabolism. Treatments with calcium gluconate can be beneficial.
CAS # 7664-39-3

hydrosulfuric acid

Hydrogen sulfide.

hydroxy acid

Any of the acids containing one or more hydroxyl (–OH) groups in addition to the carboxyl (–COOH) group, e.g., lactic acid, CH3COHCOOH).

hydroxy-iminodiacetic acid

Abbreviation: HIDA
A chemical that, when bound to radioactive technetium, is used to demonstrate the formation and flow of bile.
See: HIDA scan

hydroxybutyric acid

C4H8O3, any of the acids present in the urine, esp. in diabetic ketoacidosis, when the conversion of fatty acids to ketones increases.

hydroxycitric acid

C6H8O8, an herbal extract promoted for the treatment of weight loss. Placebo-controlled studies have not found any benefit to the treatment.
CAS # 6205-14-7

hypochlorous acid

HClO, an acid used as a disinfectant, deodorant, and bleaching agent. It is usually used in the form of one of its salts.
CAS # 7790-92-3

imino acid

An acid formed as a result of oxidation of amino acids in the body.

inorganic acid

An acid containing no carbon atoms.
Synonym: mineral acid

iocetamic acid

C12H13I3N2O3, a radiopaque agent formerly used in cholecystography.
CAS # 16034-77-8

iopanoic acid

C11H12I3NO2 , a radiopaque contrast medium used in radiographic studies of the gallbladder.
CAS # 96-83-3

keto acid

Any organic acid containing the ketone CO (carbonyl radical).

lactic acid

C3H6O3, an organic acid formed in muscles during anaerobic cell respiration in strenuous exercise. It is also formed during anaerobic muscle activity when glucose cannot be changed to pyruvic acid in glycolysis. It contributes to muscle aches and fatigue. Synonym: lactacid
CAS # 50-21-5

levulinic acid

CH3COCH2CH2COOH, an acid formed when certain simple sugars are acted on by dilute hydrochloric acid.
CAS # 123-76-2

lignoceric acid

C24H48O2, a saturated, naturally occurring fatty acid present in certain foods, including peanuts. It is also found in wood tar, various cerebrosides, and in small amounts in most natural fats. The acid is also a by-product of lignin production.
CAS # 557-59-5

linoleic acid

C18H32O2, an omega-6 fatty acid found in vegetables, nuts, grains, seeds, fruits and their oils. Oils rich in linoleic acid include (in descending order) safflower, sunflower, corn, soybean and cottonseed.
CAS # 60-33-3

linolenic acid

C18H30O2, an omega-6 fatty acid, thought to be cardioprotective. It reduces the production of cytokines and down-regulates serum cell adhesion molecules thought to be intermediates in atherosclerosis.
CAS # 506-26-3

lithic acid

An obsolete term for uric acid.

lysergic acid

C16H16N2O2, a crystalline acid derived from ergot. Its derivative, lysergic acid diethylamide (LSD), is a potent hallucinogen. See: LSD
CAS # 82-58-6

lysophosphatidic acid

Abbreviation: LPA
C21H41O7P, an acid purified from the ascitic fluid of patients with ovarian cancer. LPA stimulates the growth of ovarian cancer and may be a useful screening test for the disease.
CAS # 22002-87-5

malic acid

C4H6O5, an acid found in sour fruits such as apples and apricots and active in the aerobic metabolism of carbohydrates.
CAS # 6915-15-7

malonic acid

C3H4O4, a dibasic acid formed by the oxidation of malic acid and active in the Krebs cycle in carbohydrate metabolism. Malonic acid is found in beets. Its inhibition of succinic dehydrogenase is the classic example of competitive inhibition.
CAS # 141-82-2

mandelic acid

C8H8O3, a colorless hydroxy acid. Its salt is used to treat urinary tract infections. Synonym: phenylglycolic acid
CAS # 90-64-2

mineral acid

Inorganic acid.

methacrylic acid

C4H6O2, a colorless acid used to make methyl methacrylate.

monounsaturated fatty acid

A fatty acid containing one double bond between carbon atoms. It is found in olive oil and is the predominant fat in the Mediterranean diet. It is thought to reduce low-density lipoprotein levels without affecting high-density lipoprotein levels.
See: Mediterranean diet

muriatic acid

A nontechnical term for hydrochloric acid.
CAS # 7647-01-0

n-3 fatty acid

Omega-3 fatty acid.

n-6 fatty acid

Omega-6 fatty acid.

nicotinic acid

Niacin.

nitric acid

HNO3, a colorless, poisonous, fuming corrosive acid, widely used in industry and in chemical laboratories.
CAS # 7697-37-2

nitrous acid

HNO2, a weak acid chemical reagent used in biological laboratories.
CAS # 7782-77-6

nonvolatile acid

An acid, such as lactic acid or sulfuric acid, that accumulates in the body as a result of digestion, disease, or metabolism. It cannot be excreted from the body by ventilation but must be excreted by organs other than the lungs, e.g., by acidification of the urine.
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NUCLEIC ACID: DNA and RNA

nucleic acid

Any of the high-molecular-weight molecules that carry the genetic information crucial to the replication of cells and the manufacturing of cellular proteins. They have a complex structure formed of sugars (pentoses), phosphoric acid, and nitrogen bases (purines and pyrimidines). Most important are ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). See: illustration

octadecanoic acid

Stearic acid.

okadaic acid

C44H68O13, a toxic acid found in shellfish. The toxin is produced by oceanic phytoplankton consumed by filter-feeding marine animals such as clams, crabs, and mussels and is the cause of diarrheal shellfish poisoning. Ingestion of these shellfish by humans results in profuse watery diarrhea.
CAS # 78111-17-8

oleic acid

C18H34O2, a monounsaturated fatty acid found in most organic fats and oils.
CAS # 112-80-1

omega-3 fatty acid

, ?-3 fatty acid
Any of the long-chain polyunsaturated fatty acids found in the oils of some saltwater fish, and in canola, flaxseed, walnuts, and some vegetables. These acids include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Alpha-linolenic acid (found in flaxseed and chia) can be metabolically converted to omega-3 fatty acids in the body. People whose diets are rich in omega-3 fatty acids have a reduced incidence of cardiovascular disease. Synonym: n-3 fatty acid

omega-6 fatty acid

, ?-6 fatty acid
Any of the long-chain polyunsaturated fatty acids, such as linoleic acid and arachidonic acid, thought to influence cardiovascular and growth function when balanced with omega-3 fatty acids in eicosanoid production. Linoleic acids are derived from vegetable oils; arachidonic acids, from animal fats. Synonym: n-6 fatty acid

omega-9 fatty acid

, ?-9 fatty acid
Any of the nonessential unsaturated fatty acids that have a double carbon bond in the ninth position from the end of their fatty acid tail. They include oleic acid (present in olive oil), stearic acid, and erucic acid.

organic acid

An acid containing the carboxyl radical, –COOH. Organic acids include acetic acid, formic acid, lactic acid, and all fatty acids.

orotic acid

C5H4N2O4 , a crystalline acid occurring in milk. It is a precursor in the formation of pyrimidine nucleotides.
CAS # 65-86-1

osmic acid

Osmium tetroxide.

oxalic acid

C2H2O4, the simplest dibasic organic acid. Its potassium or calcium salts occur naturally in rhubarb, wood sorrel, and other plants. It is the strongest organic acid and is poisonous. When properly diluted, it removes ink or rust stains from cloth. It is used also as a reagent.
CAS # 144-62-7

oxaloacetic acid

, oxalacetic acid
C4H4O5, a product of carbohydrate metabolism resulting from oxidation of malic acid during the Krebs cycle. It may be derived from other sources.
CAS # 328-42-7

palmitic acid

C16H32O2, a saturated fatty acid occurring as esters in most natural fats and oils.
CAS # 57-10-3

pantothenic acid

C9H17NO5, an acid of the vitamin B complex, occurring naturally in yeast, liver, heart, salmon, eggs, and various grains. It is part of coenzyme A, which is necessary for the Krebs cycle and for conversion of amino acids and lipids to carbohydrates. Synonym: vitamin B5
CAS # 137-08-6

para-aminobenzoic acid

Abbreviation: PABA
NH2C6H4COOH, an acid of the vitamin B complex, used as a dietary supplement, an antirickettsial drug, a reagent, and a sunscreen agent. Synonym: aminobenzoic acid
CAS # 150-13-0

para-aminohippuric acid

Abbreviation: PAH, PAHA
C9H10N2O3, a derivative of aminobenzoic acid. The salt, para-aminohippurate, is used to test the excretory capacity of the renal tubules.
CAS # 61-78-9

para-aminosalicylic acid

Abbreviation: PAS, PASA
C7H7NO3, a white or nearly white, practically odorless powder that darkens when exposed to air or light. It is a second-line drug used to treat multidrug-resistant tuberculosis. Synonym: aminosalicylic acid
CAS # 65-49-6

pectic acid

C17H24O16, an acid derived from pectin by hydrolyzing its methyl ester group.

pentanoic acid

Valeric acid.

peptide nucleic acid

Abbreviation: PNA
A synthetic nucleic acid analog in which natural nucleotide bases are linked to a peptide-like backbone instead of the sugar-phosphate backbone found in DNA and RNA. PNA has numerous uses in gene regulation, splicing, and therapy; in hybridization; and as a molecular diagnostic assay.

perchloric acid

HClO4, a colorless unstable liquid compound. It is the highest oxygen-containing acid of chlorine, strong and dangerously corrosive.
CAS # 7601-90-3

phenylglycolic acid

Mandelic acid.

phosphoric acid

An acid formed by oxidation of phosphorus. The phosphoric acids are orthophosphoric acid, H3PO4; pyrophosphoric acid, H4P2O7; metaphosphoric acid, HPO3; and hypophosphoric acid, H4P2O6. The salts of these acids are phosphates. Orthophosphoric acid, a tribasic acid, is used as a 30% to 50% solution to etch enamel of teeth in preparation for bonding of resin dental restorations.
CAS # 7664-38-2

phosphorous acid

H3PO3, a crystalline acid formed when phosphorus is oxidized in moist air.
CAS # 13598-36-2

phytic acid

C6H18P6O24, a pale, water-soluble acid that is found in cereal grains and, if ingested, may interfere with the absorption of calcium and magnesium.
CAS # 83-86-3

picric acid

C6H2(NO2)3OH, a yellow crystalline powder that precipitates proteins and explodes when heated or charged. It is used as a dye and a reagent. Its salts are used in the Jaffé reaction (used to measure serum creatinine). Synonym: trinitrophenol
CAS # 88-89-1

poly DL lactic acid

Polyglactin.

polyglycolic acid

(C2H2O2)n, a polymer of glycolic acid anhydride units. It is used to manufacture surgical sutures, clips, and mesh.
CAS # 26009-03-0

polylactic acid

Polylactide.

propionic acid

C3H6O2, a carboxylic acid present in sweat.
CAS # 79-09-4

4-pyridoxic acid

C8H9NO4, a crystalline acid that is the principal end product of pyridoxine metabolism, excreted in human urine.

pyruvic acid

C3H4O3, an organic acid that plays an important role in the Krebs cycle. It is an intermediate product in the metabolism of carbohydrates, fats, and amino acids. Its quantity in the blood and tissues increases in thiamine deficiency because thiamine is essential for its oxidation.
CAS # 127-17-3

quinic acid

C7H12O6, a crystalline acid present in some plants, including cinchona bark, and berries.
CAS # 77-95-2

retinoic acid

C20H28O2, a metabolite of vitamin A used in the treatment of cystic acne.
CAS # 302-79-4

ribonucleic acid

See: RNA

ricinoleic acid

C18H34O3, an unsaturated hydroxy acid making up about 80% of fatty acids in the glycerides of castor oil. It has a strong laxative action.
CAS # 141-22-0

salicylic acid

C7H6O3, a white crystalline acid derived from phenol used to make aspirin, as a preservative and flavoring agent, and in the topical treatment of some skin conditions such as warts and wrinkles. See: chemical peeling
CAS # 69-72-7

salicyluric acid

C9H9NO4, an acid found in the urine after ingestion of salicylic acid or its derivatives.

saturated fatty acid

A fatty acid in which the carbon atoms are linked to other carbon atoms by single bonds.
See: fatty acid; unsaturated fatty acid

silicic acid

Any of a family of acids containing silica, such as H2SiO3 (metasilicic acid), H2SiO4 (orthosilicic acid), or H2SiO7 (pyrosilicic acid). When silicic acid is precipitated, silica gel is obtained.
CAS # 10193-36-9

stearic acid

C18H36O2, a monobasic fatty acid occurring naturally in plants and animals. It is used in the manufacture of soap and pharmaceutical products such as glycerin suppositories. Synonym: octadecanoic acid
CAS # 57-11-4

succinic acid

C4H6O4, an intermediate in carbohydrate metabolism.
CAS # 110-15-6

sulfonic acid

Any of the organic compounds having the general formula SO2OH, derived from sulfuric acid by replacement of a hydrogen atom.

sulfosalicylic acid

C7H6O6S3, a crystalline acid soluble in water or alcohol. It is used as a reagent for precipitating proteins, as in testing for albumin in urine.
CAS # 97-05-2

sulfuric acid

H2SO4, a colorless, corrosive, oily, viscous acid prepared from sulfur dioxide and used in many industrial processes and in clinical laboratories. Industrial accidents involving sulfuric acid through contact with skin or inhalation of aerosols are common.
CAS # 7664-93-9

sulfurous acid

H2SO3, an inorganic acid and a powerful chemical reducing agent used commercially, esp. for as a bleach.
CAS # 7782-99-2

tannic acid

C76H52O46, a mixture of digallic acid esters of d(+) glucose prepared from oak galls and sumac. It yields gallic acid and glucose on hydrolysis.
CAS # 1401-55-4

tartaric acid

C4H6O6, an acid obtained from by-products of wine fermentation. It is widely used in industry in the manufacture of carbonated drinks, flavored gelatins, dyes, and metals. It is also used as a reagent. It is thought to be an allergen.
CAS # 526-83-0

taurocholic acid

C26H45NO7S, a bile acid that hydrolyzes to cholic acid and taurine.
CAS # 81-24-3

teichoic acid

Any of the polymers found in the cell walls of some gram-positive bacteria, such as the staphylococci.

tranexamic acid

C8H15NO2, an antifibrinolytic drug that has approx. 10 times the potency of and more sustained activity than aminocaproic acid. It is used to decrease bleeding time during surgical procedures. Loss of blood is decreased when this drug is used.
CAS # 1197-18-8

trans-fatty acid

The solid fat produced by heating liquid vegetable oils in the presence of hydrogen and certain metal catalysts. Partial hydrogenation changes some of the unsaturated bonds to saturated ones. The more trans-fatty acids in the diet, the higher the serum cholesterol and low-density lipoprotein cholesterol.

trichloroacetic acid

Abbreviation: TCA
A drug used as a caustic to destroy certain types of warts, condylomata, keratoses, and hyperplastic tissue.

2,4,5-trichlorophenoxyacetic acid

2,4,5-T.

unsaturated fatty acid

An organic acid in which some of the carbon atoms are linked to other carbon atoms by double bonds, thus containing less than the maximum possible number of hydrogen atoms, e.g., unsaturated oleic and linoleic acids as compared with the saturated stearic acid. Polyunsaturated fatty acids include linoleic acid and alpha-linoleic acid.
See: fatty acid; saturated fatty acid
Enlarge picture
CLUMP OF URIC ACID CRYSTALS (×400)

uric acid

C5H4N4O3, a crystalline acid occurring as an end product of purine metabolism. It is formed from purine bases derived from nucleic acids (DNA and RNA). It is a common constituent of urinary stones and gouty tophi. See: illustration
CAS # 69-93-2

Output

Uric acid must be excreted because it cannot be metabolized. Uric acid output should be between 0.8 and 1g/day if the patient is on an ordinary diet.

Increased elimination is observed after ingestion of proteins and nitrogenous foods, after exercise, after administration of cytotoxic agents, and in gout and leukemia. Decreased elimination is observed in kidney failure, lead poisoning, and in those who eat a protein-free diet.

valeric acid

C5H10O2, an oily fatty acid having a distinctly disagreeable odor, existing in four isomeric. Synonym: pentanoic acid
CAS # 109-52-4

valproic acid

Abbreviation: VPA
C8H16O2, an acid used to treat seizure disorders.
CAS # 99-66-1

vanillylmandelic acid

, vanilmandelic acid Abbreviation: VMA
C9H10O5, a principal metabolic product of catecholamines. VMA makes up approx. 90% of the metabolites of the catecholamines epinephrine and norepinephrine and is secreted in the urine. People with pheochromocytoma produce excess amounts of catecholamines; therefore there are increased amounts of VMA in their urine.
CAS # 55-10-7

volatile acid

An acid produced from carbon dioxide (CO2). It can be excreted by the body by ventilation (colloquially, “blowing off CO2”).

xanthurenic acid

C10H7NO4, an acid excreted in the urine of pyridoxine-deficient animals after they have been fed tryptophan. Synonym: 4,8-dihydroxyquinaldic acid
CAS # 59-00-7

deoxyribonucleic acid

See DNA.

deoxyribonucleic acid

see DNA.

Deoxyribonucleic acid (DNA)

The genetic material in cells that holds the inherited instructions for growth, development, and cellular functioning.

deoxyribonucleic acid

; DNA nucleic acid within chromosomes of cells and many viruses; the 'genetic fingerprint' of the individual

de·ox·y·ri·bo·nu·cle·ic ac·id

(DNA) (dē-oks'ē-rī'bō-nū-klē'ik as'id)
The type of nucleic acid containing deoxyribose as the sugar component; found principally in the nuclei (chromatin, chromosomes) and mitochondria of animal and plant cells, usually loosely bound to protein (hence the term deoxyribonucleoprotein).

deoxyribonucleic acid (DNA) probes,

n a nucleic acid fragment labeled with a radioisotope that is complementary to a sequence in another nucleic acid fragment that will bind to it and thus identify it. It is used as a diagnostic tool to identity the species of microbe involved in an infectious process such as refractory periodontal disease.

deoxyribonucleic acid

a nucleic acid occurring in cells as the basic structure of the genes. DNA is present in all body cells of every species, including unicellular organisms and DNA viruses. The structure of DNA was first described in 1953 by J.D. Watson and F.H.C. Crick.
DNA molecules are long linear polymers of small molecules called nucleotides, each of which consists of one molecule of the five-carbon sugar deoxyribose bonded to a phosphate group and to one of four heterocyclic nitrogenous compounds referred to as bases. A single strand of DNA is made by linking the nucleotides together in a chain with bonds between the sugar and phosphate groups of adjacent nucleotides. It thus consists of a backbone of alternating sugar and phosphate groups with a base attached to each sugar as a side chain. The four bases are two purines, adenine (A) and guanine (G), and two pyrimidines, cytosine (C) and thymine (T). Single-stranded DNA can be synthesized with any specified sequence of bases, but in living cells the base sequence has a meaning; it specifies the amino acid sequence of all of the polypeptides and proteins made by the cell. And since all of the enzymes that catalyze biochemical reactions are proteins, the DNA contains the specifications for all of the biochemistry and structure of the cell.
The chemical basis of the genetic code lies in the ability of the bases to form hydrogen bonds with each other. Unlike the covalent bonds holding together the atoms of a single strand of DNA, hydrogen bonds are weak and easily broken and reformed. Hydrogen bonding is governed by the base pairing rule: A always bonds with T, and C always bonds with G. A and T (or C and G) are called complementary bases. The genetic information is read and preserved by the matching up of complementary bases.
In cells, the DNA is double-stranded. The configuration of the DNA molecule resembles a ladder in which the sides are the sugar-phosphate backbones, which are antiparallel (they run in opposite directions), and the rungs are hydrogen-bonded complementary bases; thus, the entire sequence along the two strands is complementary. This whole structure is twisted so that the two strands form a double helix. Once before each cell division, a group of proteins splits the two strands apart, and as complementary nucleotides bond to the bases of each strand they are jointed to form a new strand. This process is called replication. It results in the exact duplication of the DNA molecule, because each strand serves as a template (pattern) for the synthesis of its complementary strand. When the cell divides, one copy goes to each daughter cell. Thus, the genetic information is passed on from generation to generation without change except for rare mutations, which result from copying errors or incorrectly repaired breaks in the DNA molecule that change the base sequence.
The reading of the genetic code involves two processes: transcription and translation. In transcription, a length of DNA is used as a template to make a complementary strand of messenger RNA (mRNA). RNA (ribonucleic acid) is a nuceic acid like DNA. The only differences are that the sugar, ribose, has an extra oxygen atom, and the pyrimidine base, uracil (U), which also pairs with adenine, replaces thymine. In translation, the mRNA molecule is read by a structure called a ribosome, which produces the polypeptide specified by the mRNA message.
The genetic code is a triplet code. Every triplet of bases along the strand specifies a single amino acid. There are 64 possible triplets (codons) that can be formed from the four bases. Each one specifies that one of 20 different amino acids be inserted in a growing polypeptide chain or marks either the start or the end of a chain.
Two other types of RNA are involved in translation. Ribosomal RNA (rRNA) forms a large part of the ribosome. Transfer RNA (tRNA) is the means by which codons are matched with amino acids. tRNAs are small molecules with several self-complementary sections so that they fold up into a compact structure owing to bonding between complementary bases. One end of the molecule is a three-base anticodon, which bonds to its complementary codon on mRNA molecules. The other end is recognized by a specific enzyme which attaches the correct amino acid to it. During translation, the ribosome proceeds along the mRNA molecule and, as each codon is matched by a specific tRNA, the amino acid it carries is transferred to the growing polypeptide chain, and the process is repeated until the 'stop' codon is reached. Like the mRNA molecules, rRNA and tRNA molecules are formed on DNA templates; the genetic material contains not only the information for polypeptide sequences but also for rRNA and tRNA sequences.
The chromosomes of mammalian cells contain 3 × 109 base pairs which is enough to code for the 100,000 or so enzymes and structural proteins. Less than 10% of the DNA codes for proteins and RNA, the rest is noncoding, also referred to as 'junk' DNA, and is of uncertain purpose. DNA is the molecule that directs all of the activities of living cells, including its own reproduction and perpetuation in generation after generation.
References in periodicals archive ?
Epigenetic: Referring to heritable changes in phenotype or gene expression caused by mechanisms other than changes in the underlying deoxyribonucleic acid (DNA) sequence.
This is in bold contrast to deoxyribonucleic acid and protein concentrations, which show that when zymogens have damaged the acinar tissue, the protein synthesis has greatly decreased.
Crick and Watson of the United States discovered the double-helix structure of deoxyribonucleic acid, or DNA, in 1953 while working in Cavendish Laboratory in Britain.
Modern life has settled on a tried-and-true plan, with the starring molecules consisting of proteins and deoxyribonucleic acid (DNA).
Actual Innocence by Barry Scheck, Peter Neufeld, and Jim Dwyer explores the science of deoxyribonucleic acid (DNA) analysis and examines its importance not only as a crime-fighting tool but as a truth-finding tool that has assisted in winning the freedom of dozens of people who were wrongfully convicted of crimes that they never committed.
GAO-02-488R March 6, 2002 Text The National Interagency Canada Lynx Survey (Protocol) was designed to determine the presence of Canada lynx through deoxyribonucleic acid (DNA) analysis of hair samples recovered from scratch pads in forests in the northern United States.
DNA stands for deoxyribonucleic acid, the molecular basis of heredity.
In addition, the Wisconsin law defines "genetic test" as "a test using deoxyribonucleic acid extracted from an individual's cells," even though most genetic testing does not utilize DNA.
This Frost & Sullivan research service titled Strategic Analysis of the European DNA Microarrays Market provides a detailed analysis of the status and future opportunities for vendors in the European deoxyribonucleic acid (DNA) microarrays market, especially for research applications.
The Authorities currently have the ability to detect Hepatitis C (HCV) ribonucleic acid (RNA), Human Immunodeficiency virus (HIV) RNA and Hepatitis B (HBV) deoxyribonucleic acid (DNA) in donations from blood, tissue and stem cell donors.
RNA viruses have ribonucleic acid as their genetic material (rather than deoxyribonucleic acid, or DNA).
PESHAWAR, February 15, 2012 (Balochistan Times): The Deoxyribonucleic Acid (DNA) of majority people of Khyber Pakhtunkhwa and FATA matching the inhabitants of Central & South Asia and Eastern Europe while the DNA of Peshawarits is similar to the residents of Kandahar and North Afghanistan.

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