Any of many antigens that are part of a bacterial capsule or form on the outer portion of a cell wall.
2. k selection
Definition:
In evolution, the selection of traits that aid an organism's competitive capability when the population is at or near its carrying capacity.
3. K-RAS
Definition:
A proto-oncogene that has point mutations and is associated with melanoma, thyroid carcinoma, and acute myelogenous and lymphoblastic leukemia.
4. kaemferol
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chemical structure
Definition:
A flavone-ring-containing plant pigment found in many angiosperms (flowering plants).
5. kames
Definition:
Mounds of poorly sorted glacial drift, mostly sand and gravel, deposited near the front of a glacier.
6. kanamycin
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chemical structure
Author: Susan
A.Hagedorn
Definition:
An antibiotic of the aminoglycoside family that poisons translation by binding to the ribosomes.
7. Kaposi's sarcoma (multiple idiopathic hemorrhagic sarcoma)
Definition:
A type of vascular cancer characterized by soft purple nodules that usually develop first on the feet and then slowly spread across the skin. This cancer is most often found in people with compromised immune systems, such as AIDS patients.
8. kappa chain
Definition:
Either of two types of light chains (small polypeptide chains) that are found in immunoglobulins.
9. karnal blunt
Definition:
A fungal wheat disease caused by Tilletia indica.
10. karyocyte
Definition:
General scientific term for any cell with a nucleus.
11. karyoevolution
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
Evolutionary change in the chromosome set, expressed as changes in number and gross structure of the chromosomes; (more broadly), evolutionary relationships between taxa as indicated by karyotype differences.
12. karyogamy
Definition:
The fusion of two nuclei.
13. karyology
Definition:
The scientific study of chromosomes; this usually involves the study of their general shape and banding patterns.
14. karyolysis
Definition:
The destruction of a cell's nucleus.
15. karyomegaly
Definition:
The condition of a cell's nucleus being abnormally enlarged (i.e., for reasons other than it being polyploid).
16. karyoplasm (nuclear sap)
Definition:
Areas within a nucleus that seem to contain only clear fluid.
17. karyoplast
Definition:
18. karyorrhexis
Definition:
Degeneration or fragmentation of a cell's nucleus.
19. karyosome
Definition:
The central portion of a cell's nucleus that typically contains a glob of heterochromatin.
20. karyotype (adj. karyotypic)
Definition:
A karyotype is a photomicrograph of an individual's chromosomes arranged in a standard format showing the number, size, and shape of each chromosome type. Each chromosome is characterized by the length of its arms and the location of its centromere, which appears as an indentation or a lightly stained region. Staining methods may result in banding on the chromosomal arms (chromatids); chromosomes can then be identified according to their banding pattern. Karyotypes are used in low-resolution physical mapping to correlate chromosomal abnormalities with the characteristics of specific diseases.
21. kasugamycin (kasumin)
Definition:
An aminoglycoside antibiotic used against bacteria and some fungi; it is unusual because it is bacteriostatic (inhibits bacterial growth and reproduction) rather than bacteriocidal.
22. Kawasaki's disease (mucocutaneous lymph node syndrome)
Author: Guo Li
Definition:
This disease occurs mainly in children, and is characterized by fever that lasts longer than 5 days and which is not responsive to antibiotic treatment, plus the following mucocutaneous manifestations:
A major complication is arteritis and aneurysm formation of the coronary vessels, myocarditis, pericarditis and acute myocardial infarction.
23. keel
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
A ridge like the keel of a boat; in particular, a boat-shaped structure formed by fusion of the two anterior petals of a flower.
24. keeled
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
Of leaves or bracts, folded and ridged along the midrib.
25. Kell blood group system
Definition:
Blood type classification based on a group of erythrocyte antigens that is characterized by an antibody called anti-K.
26. keloid
Author: Guo Li
Definition:
A keloid is a hypertrophic scar due to fibrous nodular growth in a healing process.
27. keratin
Definition:
A fibrous, insoluble, sulfur-containing protein that serves as the main structural molecule in hair and nails and is also present in the skin.
28. keratinocyte
Definition:
A skin cell that makes keratin.
29. keratitis
Author: Guo Li
Definition:
Keratitis is the inflammation of the cornea, the clear covering of the front of the eye.
30. keratosis
Definition:
Any horny growth on the skin, such as a wart.
31. keratotomy
Author: Guo Li
Definition:
Keratotomy is surgical incision on the cornea for the correction of myopia (nearsigtedness) and/or astigmatism (an irregular cornea that results in blurred vision).
32. kernel blight
Definition:
Any of a group of fungal diseases of barley which cause withering and discoloration of the grain; Gibberella zeae, Helminthosporium sativum and Alternaria are typically the culprits.
33. kernel spot
Definition:
A fungal disease of pecans that causes irregular brown spots on the nuts; it is caused by Coniothyrum caryogenum.
34. kernicterus
Author: Guo Li
Definition:
Kernicterus is a clinical syndrome afflicting newborns which is caused by high levels of unconjugated bilirubin which passes the immature blood-brain barrier of the newborn and causes degeneration of cells of the basal ganglia and hippocampus. An affected child displays a range of neurologic disorders: hypertonia, seizure, and cerebral palsy. In severe cases, death is likely.
35. Kernig's sign
Author: Guo Li
Definition:
Kernig's sign is a clinical sign which is present in meningitis. The subject lies down on his or her back and a thigh is flexed to form a right angle with the trunk (i.e. perpendicular to the plane the subject is lying). The examiner then attempts to extend the leg. A positive Kernig's sign is present if complete extension of the leg is not possible because of limitation by pain.
36. kerosine fungus (creosote fungus)
Definition:
An asexual fungus (Hormoconis resinae in the family Amorphothecaceae) that is found in the air and soil which can grow in and block the fuel filters of jet engines.
37. ketoacidosis
Author: Guo Li
Definition:
Ketoacidosis is the condition of acid in the blood due to the accumulation of ketone bodies.
38. ketone
Definition:
A carbon atom double-bonded to an oxygen and single-bonded to two chemical groups (such as methane, benzene, anything besides hydrogen). The carbon-oxygen double bond part is known as a carbonyl group (-C=O). An example is acetone, which is a carbonyl group attached to two methanes (methyl groups: -CH3).
39. ketone body (acetone body, ketone bodies)
Definition:
Any of the three compounds created by acetyl coenzyme A (acetoacetate, hydroxybutyrate, and acetone) which are water-soluble cellular fuels normally exported by the liver. They can build up in the blood and body tissues because of starvation, untreated diabetes mellitus, or other disorders that interfere with carbohydrate metabolism.
The body rids itself of ketones mainly through urine, but it rids itself of acetone through the lungs, which gives the breath a characteristic fruity odor. If ketones build up in the body long enough, they cause serious illness and coma (see ketoacidosis.)
40. ketonemia (acetonemia)
Definition:
Medical term describing the condition of having excess ketone bodies in the bloodstream.
41. ketonuria
Definition:
The presence of ketone bodies in the urine; this is a symptom of diabetes mellitus.
42. ketose
Definition:
A simple sugar that has a ketone as its carbonyl group.
43. ketosis
Definition:
A metabolic disorder in which ketone bodies are at high levels in the blood, body tissues and urine.
44. ketosteroid
Definition:
A steroid-like chemical which is a by-product of the breakdown of certain steroids; they are found in urine and measuring them can give a good indication of the level of androgen production in the body. The major ketosteroids are:
45. kidney disease (nephropathy)
Author: PharmInfoNet
Definition:
Any one of several chronic conditions that are caused by damage to the cells of the kidney. People who have had diabetes for a long time may have kidney damage.
46. kidney failure (renal failure)
Author: Guo Li
Definition:
Kidney failure is the decrease in the glomerular filtration rate. The most often used laboratory test is serum creatinine (normal 50 to 100 umol/L). If a subject is totally without kidney function, serum creatinine rises by about 80 to 120 umol/L per day.
47. kidneys
Author: PharmInfoNet
Definition:
Two organs in the lower back that clean waste and poisons from the blood. The kidneys are shaped like two large beans, and they act as the body's filter. They also control the level of some chemicals in the blood such as hydrogen, sodium, potassium, and phosphate.
48. killer cell (K cell)
Definition:
An effector cell, such as a cytotoxic T cell, leukocyte or macrophage, that regulates antibody-dependent cell toxicity.
49. killer yeast
Definition:
A yeast that secretes a toxin that can kill other yeasts.
50. kilobase (kb)
Definition:
Unit of length for DNA fragments equal to 1000 nucleotides.
51. kinase
Definition:
Any of several enzymes that catalyze the transfer of a phosphate group from one molecule to another.
52. kinetics
Definition:
53. kinetin (cytokinin 6-furfurylaminopurine)
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Definition:
A powerful plant growth factor found in the callus tissue of tobacco plants.
54. kinetochore
Definition:
A platelike structure necessary for chromosomal movement during mitosis; it develops on the centromere and links the chromosomes to the mitotic spindle.
55. kinetoplasm
Definition:
The highly contractile part of a cell's cytoplasm.
56. kinetoplast
Definition:
A network of interlocked DNA circles found in mitochondria.
57. kingdom
Definition:
The topmost taxonomic rank, immediately above phylum or division.
This dictionary recognizes five biological kindoms:
58. Kingdom Animalia
Definition:
The members of this kingom are complex, multicellular, eukaryotic organisms that digest food outside their cells and then absorb the digested nutrients. Animals must consume other organisms to obtain most of their nutrients.
59. Kingdom Fungi (sing. fungus)
Definition:
Kingdom Fungi includes organisms such as slime molds, mushrooms, smuts, rusts, mildews, molds, stinkhorns, puffballs, truffles and yeasts. All are classified in this kingdom because they absorb food in solution directly through their cell walls and reproduce through spores. None conduct photosynthesis.
60. Kingdom Monera (prokaryotes, monerans)
Definition:
This biological kingdom is composed of bacteria and cyanobacteria, one-celled (sometimes colonial) organisms whose cells lack a nuclear envelope, mitochondria, or plastids. They reproduce asexually through fission (splitting in two) and mainly gain their nutrition by absorbing it from their environment (though some species are chemoautotrophs or photosynthetic).
61. Kingdom Monera
Definition:
This is the most primitive of the five kingdoms; it encompasses all the bacteria. Monerans are single-celled prokaryotic organisms.
62. Kingdom Plantae
Definition:
The members of this kingdom are multicellular, eukaryotic organisms that (usually) conduct photosynthesis.
Compare Kingdom Fungi and Kingdom Animalia.
63. Kingdom Protista (protists)
Definition:
This biologic kingdom is composed of eukaryotic organisms: unicellular and multicellular algae, slime molds, and unicellular or simple colonial protozoans. Protists obtain their nutrition via several methods, including photosynthesis, devouring other organisms, and absorption. Protists can reproduce sexually or asexually, and they can be sedentary or move with pseudopods, flagella, or cilia. There are over 55,000 known living species and over 35,000 known extinct species in this kingdom.
64. Kingdom Protista
Definition:
This kingdom is composed of single-celled (sometimes multicellular), eukaryotic organisms. Protists are more complex than bacteria and include protozooans and some types of algae.
65. Klebsiella
Definition:
Klebsiella is a genus of Gram-negative, rod-shaped bacteria in the family Enterobacteriaceae. Facultative anaerobes, they are found in the intestinal and repiratory tracts of many vertebrates (including humans) and are commonly responsible for bladder, kidney, lung, and wound infections. K. pneumoniae can cause pneumonia in people with compromised immune systems.
66. Kleinschmidt monolayer technique
Definition:
A techniqe for preparing DNA for study under an electron microscope; the DNA molecules are spread as a thin, positively charged protein film on water. The film is then transferred to a copper viewing grid and placed under the 'scope.
67. Klenow fragment
Definition:
The larger of the two pieces of DNA polymerase I left after proteolytic cleaving; the fragment lacks the 5'-3' exonuclease activity of the whole enzyme but retains its DNA polymerase and 3'-5' exonuclease properties.
68. kleptoparasite
Definition:
An organism that gets its food by scavenging or stealing it from another organism that it lives in close association with.
69. Klinefelter syndrome (XXY trisomy)
Definition:
A genetic syndrome in many mammals caused by the presence of an extra X chromosome in the male (normally XY) karyotype. In humans, this syndrome is characterized by small testes, feminine appearance, sterility (except in the case of genetic mosaics) and possibly mental retardation. In domestic cats, male calicos always have this genetic condition.
70. Klinefelter's syndrome
Author: Guo Li
Definition:
Klinefelter's syndrome is a genetic disorder that afflicts some males and is characterized by tall stature, infertility, abnormal breast tissue development and abnormally small reproductive organs. The affected individuals are genetically XXY.
71. klinokinesis
Definition:
Any change in the movement of a cell that involves it changing its direction.
72. Klippel-Feil syndrome
Author: Guo Li
Definition:
Klippel-Feil syndrome is characterized by the congenital fusion of two or more cervical vertebrae, resulting in a short and rigid neck.
73. knock-knees
Author: Guo Li
Definition:
"Knock-knees" is the condition in which the legs curve inward (genu valgum) so that the knees knock together when walking.
74. koilonychia
Author: Guo Li
Definition:
Koilonychia is a medical term for thin, brittle fingernails.
75. Koplik's spots
Author: Guo Li
Definition:
Koplik's spots are tiny red vesicular lesions with blue-white centers on the mucous membranes of the cheek, inner conjunctival folds and vagina. Koplik's spots indicate that the patient has a measles infection; the spots appear about 2 days before the characteristic rash and last 1 to 4 days.
76. Kornberg, Arthur
Definition:
A U.S. biochemist who was co-awared the Nobel Prize for discovering some of the enzymes responsible for DNA synthesis.
77. Korsakoff's syndrome
Author: Guo Li
Definition:
Korsakoff's syndrome is characterized by confusion, impairment of memory, and unconscious falsification of experience to fill in memory gaps. This syndrome is frequently found in alcoholics.
78. Krebs cycle (citric acid cycle, tricarboxylic acid cycle)
Definition:
A complex series of reactions following glycolysis in aerobic respiration that convert pyruvic acid into hydrogen, carbon dioxide and electrons.
79. Krebs, Hans Adolph
Definition:
A German-born British chemist (1900-1981) who was awarded the Nobel for his research in intermediate metabolism.
80. kreotoxin
Definition:
81. Kussmaul's breathing
Author: Guo Li
Definition:
This is the increased depth and rate of breathing; a clinical sign associated with metabolic acidic condition, especially diabetic acidosis.
82. kwashiorkor
Definition:
A nutritional deficiency illness in children who aren't getting enough protein; this results in anemia, poor growth, weakness, and edema (which is particularly characterized by a pronounced pot belly). In famine-stricken regions, children typically develop kwashiorkor right after they are weaned.
83. kyphosis
Author: Guo Li
Definition:
Kyphosis is an exaggerated backward curving of the thoracic part of the vertebral column.
END
