The U.S. agency responsible for regulation of biotechnology products in plants and animals. The major laws under which the agency has regulatory powers include the Federal Plant Pest Act (PPA), the Federal Seed Act, and the Plant Variety Act (PVA). In addition, the Science and Education (S&E) division has nonregulatory oversight of research activities that the agency funds.
2. u1RNA
Definition:
A common form of RNA that is an element of small nuclear RNA (snRNA) in the nuclei of mammalian cell; it functions to splice in or remove exons of messenger RNA.
3. ubiquinone (coenzyme Q)
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chemical structure
Definition:
An enzyme that serves as an electron carrier in cellular electron transport; it is closely related to Vitamin K.
4. ubiquitin
Definition:
A 76-amino acid polypeptide that latches onto a cellular protein right before that protein is broken down. Ubiquitin is found in yeast (Saccharomyces cerevisiae and in most eukaryotic cells.
5. Udden-Wentworth scale
Definition:
A geometric scale of grain sizes which classifies particles of siliciclastic sediment from 4096 millimeters (boulders) in size down to 0.00006 millimeters (clay). This scale is almost universally accepted by modern sedimentologists (a type of geologist). It was first proposed in 1898 by Udden and then modified and extended in 1922 by Wentworth.
6. UI RNA
Definition:
A common type of small nuclear RNA (165 bases long) that serves to splice and/or remove exons of messenger RNA.
7. ulcer
Definition:
A sore, often deep, sometimes inflamed, which heals slowly or not at all. Stomach ulcers are caused by a bacterium called H. pylori
8. ulcerative colitis
Author: Guo Li
Definition:
Ulcerative colitis is a form of inflammatory bowel disease that involves the mucosa of the colon. The common symptoms are bloody diarrhea and stomach cramps; patients usually have anemia and low serum albumin. Abdominal x-ray films show a dilated colon. The diagnosis is confirmed by biopsy of the mucosa.
9. ulcerative lymphangitis
Definition:
A disease of horses and cattle caused by bacteria in the genus Corynebacterium; it causes infection and swelling in the lymph nodes and ulceration of wounds (typically abrasions on the leg) that are the site of entry for the bacteria.
10. uliginous
Definition:
Describes a plant that grows in a swamp or wetland.
11. ulna
Definition:
The ulna is the longer of the two bones of the forearm (the shorter being the radius).
12. ulnar nerve
Author: Guo Li
Definition:
The ulnar nerve is the nerve that supplies part of the cutaneous nerves to the hand that innervates the area of the small finger and the lateral half of fourth digit. It also supplies for the motor innervation of the small muscles for the adduction of the fingers.
13. ultisols
Author:
Definition:
Highly weathered soils having significantly more clay in the B-horizon than in the A-horizon and having low base status; acidic soils common in the Southwest.
14. ultrafiltration fermenter
Definition:
An apparatus for continuous fermentation that is run in conjunction with a continuous microfiltration system to constantly remove the low-molecular-weight product of the fermentation.
15. ultrasound (US)
Author: Fertilitext
Definition:
The use of high-frequency sound waves for creating an image of internal body parts.
16. ultraviolet radiation (UV)
Definition:
Electromagnetic radiation with wavelengths between 200 nanometers and 400 nanometers. Exposure to excessive UV radiation damages DNA and can cause health problems such as skin cancer and cataracts in the eyes.
17. umbel
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
A racemose inflorescence in which all the individual flower stalks arise in a cluster at the top of the peduncle and are of about equal length.
18. umbellate
Author: Mirrored from
Dave Sutton's Aquatic Plant
Glossary
Definition:
Bearing umbels; consisting of umbels; forming an umbel or umbels.
19. umbilicus
Definition:
The belly button; the scar or stub that marks the place where the umbilical cord was attached.
20. unbalanced translocation
Definition:
A genetic translocation that results in the loss of a part of a chromosome or causes other genome damage.
21. uncertainty factor (safety factor, UF)
Author: Biological Sciences at
Heriot-Watt University
Definition:
This term may be used in either of two ways depending upon the context
The value of the safety factor depends on the nature of the toxic effect, the size and type of the population to be protected, and the quality of the toxicological information available.
22. uncinate
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
Terminating in a hooked point.
23. uncoating
Definition:
Releasing viral nucleic acid from a virus or exposing the interior of a virus enough to facilitate replication by stripping away the outer layers of the viral coat.
24. unconsolidated parent material
Author:
Definition:
Material from which a soil develops.
25. uncoupling agent
Definition:
A chemical that breaks the electron transport chain during key biological processes (e.g., photosynthesis, phosphorylation).
26. undercut bank
Author:
Definition:
A bank that has had its base cut away by the water action along man-made and natural overhangs in the stream.
27. undercutting
Author:
Definition:
Erosion of the stream bank toe resulting in an overhang. If the bank is stable (a solid system of tree roots to hold the soil together), the undercut is usually an excellent fish habitat feature; if the bank is unstable soil or a man-made structure, undercutting is likely to lead to bank failure as the unsupported material collapses.
28. underflow
Author:
Definition:
That portion of a stream which is flowing through the permeable deposits underlying the surface stream. The measured flow of a stream does not normally include underflow. Underflow is not the same as groundwater.
29. undifferentiation
Definition:
A condition in which tumor or cancer cells lose normal cell organization, function and differentiation.
30. undulate
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
31. unequal crossing over
Definition:
A situation in genetic recombination that causes one pair of chromatids ending up with only one copy of a segment, while the other pair gets three copies of the segment.
32. unguentum (ung.)
Definition:
This Latin term, which is frequently used in medicine and pharmacy, means "ointment".
33. unicellular
Definition:
Describes an organism (such as a diatom) that has only one cell.
34. unifoliate
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
Having one leaf.
35. unifoliolate
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
Of a leaf, basically compound, but reduced to only one leaflet.
36. uniform flow
Author:
Definition:
A flow in which the velocities are the same in both magnitude and direction from point to point. Uniform flow is possible only in a channel of constant cross section and gradient.
37. uniform rate hypothesis
Definition:
This states that any two evolving organismal lineages diverge from a common ancestor at a constant rate with respect to each other.
38. unilateral
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
39. unilocular
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
40. unimpaired flow
Author:
Definition:
The natural flow of a stream without regulation, control, diversion, or artificial additions.
41. unineme hypothesis
Definition:
This states that that a chromatid has only one DNA duplex, which goes from one end of the chromatid to the other.
42. uniparental inheritance
Definition:
A type of inheritance in which the offspring of a mating has the phenotype (observable physical traits) of only one parent.
43. uniport
Definition:
The transport of only one solute across a membrane; compare cotransport.
44. unique DNA
Definition:
Any nucleotide sequence in DNA that is found only once in a given genome.
45. unique species
Author:
Definition:
A biotic resource whose presence is unusual and of special interest due to extremities of range, special soil types, or unusual associations with other species.
46. unisexual
Definition:
Describes an organism that is male or female; i.e., has the reproductive organs of only one sex.
47. unisexual
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
Bearing only male or only female reproductive organs.
48. unit character
Definition:
A particular trait or characteristic (usually controlled by a single gene or a set of inseparable genes) that is passed on as a unit in heredity.
49. united
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
Fused together.
50. universal antidote
Definition:
A preparation of activated charcoal that can adsorb and therefore neutralize many toxic chemicals.
51. universal tube
Definition:
A straight, cylindrical glass vial that holds about 25 milliliters and is topped with a screw-on cap.
52. unsaturated fat
Definition:
A fat that contains a carbon-carbon double bond.
53. unsaturated fats (monounsaturated fats, polyunsaturated fats)
Definition:
A fat that contains a carbon-carbon double bond, or a fat containing unsaturated fatty acids; such a fatty acid has double or triple covalent bonds and is thus able to add more atoms. Unsaturated fats are believed to lower blood cholesterol levels and are found at high levels in vegetable oils (olive oil, safflower oil, etc.) As a general rule, unsaturated fats are liquid at room temperature.
54. unscheduled DNA synthesis
Definition:
Any synthesis of DNA that happens ouside the S phase of the cell cycle.
55. unstable angina
Author: Guo Li
Definition:
Angina which, in comparison with previous pattern, occurs with less degree of exertion; or with the same degree of exertion but the angina is more severe, the affected area more extensive, or associated with more debilitating symptoms.
This type of angina has a pattern that is symptomatic of a high chance to get a heart attack unless the patient is treated immediately.
56. unstable mutation
Definition:
A mutation that has a high likelihood of reverting to its original form.
57. unsteady flow
Author:
Definition:
Flow on rising or falling stages.
58. untranscribed spacer
Definition:
In a DNA strand, a spacer sequence that lies between two coding genes. Spacer sequences aren't transcribed by RNA polymerase.
59. up mutation
Definition:
Refers to any mutation in the promoter region of a gene which can trigger transcription initiation.
60. upflow sludge blanket
Definition:
An apparatus for anaerobic digestion in which the microbes form thick flocculations that are kept suspended near the bottom of the reaction tank.
61. upland
Author:
Definition:
Any area that does not qualify as a wetland because the associated hydrologic regime is not sufficiently wet to elicit development of vegetation, soils and/or hydrologic characteristics associated with wetlands. Such areas in floodplains are more appropriately termed nonwetlands.
62. upland
Author:
Definition:
Generally a land zone sufficiently above or away from freshwater bodies, watercourses, and surface-emergent aquifers to be largely dependent on precipitation for its water supplies.
63. upper bank
Author:
Definition:
That portion of the topographic cross section from the break in the general slope of the surrounding land to the normal high water line.
64. upper gastrointestinal tract
Author: Guo Li
Definition:
This refers to the alimentary tract from mouth to the stomach
65. upper respiratory tract
Author: Mirrored from
Tsute Chen's
Glossary of Microbiology
Definition:
The nasopharynx, oral cavity, and throat.
66. upstream
Author: Susan
A.Hagedorn
Definition:
67. upstream activation site (upstream activator sequence)
Definition:
A DNA sequence that regulates transcription like an enhancer but doesn't work if it's located downstream from a promoter.
68. uracil
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the chemical structure
Definition:
A nitrogenous base normally found in RNA but not DNA; uracil is capable of forming a base pair with adenine.
69. urate (uric acid)
Author: Guo Li
Definition:
This is a purine by-product of the metabolism of DNA.
Normal blood range: 140 to 450 umol/L
70. urate oxidase
Author: Biological Sciences at
Heriot-Watt University
Definition:
This is the hepatic peroxisomal enzyme which catalyses the oxygen-mediated conversion of uric acid into allantoin.
71. urceolate
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
Urn-shaped.
72. urea (carbamide)
Definition:
This water-soluble by-product of protein metabolism was the first organic compound to be synthesized in the lab (in 1824). Commercially, it is used in adhesives, animal feed, cosmetics, fertilizer, plastics, and is used as a stabilizer in explosives and as a diuretic.
73. urea cycle
Definition:
The metabolic pathway is found in vertebrates and takes place in the liver; in it, urea is synthesized from amino acids and carbon dioxide.
74. ureaplasma
Author: Fertilitext
Definition:
A microorganism that can infect peoples' bladders; ureaplasmas are similar to mycoplasmas.
75. urease
Definition:
An enzyme that breaks urea down into carbon dioxide and ammonia; it's typically used to measure urea concentrations.
76. uredospore (uridiaspore)
Definition:
A type of spore formed by a rust known as "summer spores." In Puccinia graminis the uredospore occurs on wheat. Compare: teliospore.
77. uremia
Author: Guo Li
Definition:
Although the term "uremia" literally means the presence of urea (a nitrogenous product of metabolism usually cleared by the kidney) in the blood, it is the complex terminal stage of kidney failure.
78. ureotelic
Definition:
Describes an organism that excretes excess nitrogen as urea.
79. urethra
Author: Fertilitext
Definition:
The tube through which urine from the bladder is expelled.
80. urethral caruncle
Author: Guo Li
Definition:
A urethral caruncle is a small red fleshy swelling composed of granulomatous tissue presenting at the posterior lip of the external meatus, commonly seen after menopause.
81. urethritis
Definition:
Urethritis is an infection or imflammation of the urethra, the tube through which urine leaves the bladder.
82. uric acid
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chemical structure
Definition:
This chemical is the end product of purine catabolism in humans and other primates and is present in urine.
83. uricotelic
Definition:
Describes an organism that excretes excess nitrogen as uric acid.
84. uridine triphosphate (UTP)
Definition:
A molecule which consists of the nitrogenous base uracil linked to the sugar ribose and which has a chain of three phosphate groups attached to the ribose in a linear fashion. UTP is required during transcription since it is a direct precursor of RNA.
85. urinary incontinence
Author: Guo Li
Definition:
Urinary incontinence is the inability to control the emptying of the urinary bladder which normally produces the first urge to void at a volume of about 150 ml and a marked sense of fullness at about 400 ml.
86. urogastrone
Definition:
This polypeptide is secreted by the salivary glands and functions to inhibit the secretion of gastric acids in the stomach.
87. urologist
Definition:
A medical doctor who specializes in urology.
88. urology
Definition:
A branch of medicine concerned with the diagnosis and treatment of diseases of the urinary tract and urogenital system.
89. urticaria
Author: Guo Li
Definition:
Urticaria is an eruption of wheals or hives and is often itchy. It is often caused by IgE-mediated immune response involving mast cells.
90. usnic acid
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chemical structure
Definition:
An organic acid extracted from the lichen Usnea barbata which has antibiotic properties, particularly against Gram-positive bacteria such at M. tuberculosis as well as some pathogenic fungi.
91. ut dictum (ut dict.)
Definition:
This Latin term, which is frequently used in medicine and pharmacy, means "as directed".
92. uterine contractions (Braxton-Hicks contractions)
Author: Guo Li
Definition:
Braxton-Hicks contractions are involuntary contractions of the uterus in association with pregnancy. If the contractions become more intense, more frequent and regular in time, they may be the beginning of true labor.
Braxton-Hicks contractions are not associated with pain and are transient, often begin to be felt at about 28 weeks of pregnancy and increase in regularity.
93. uterus
Author: Fertilitext
Definition:
The womb; the pear-sized female reproductive organ that noursishes the fetus until birth.
94. uterus (womb)
Author: Guo Li
Definition:
The uterus is a hollow, thick-walled organ about the size of a fist. It is composed of the uterine body and the cervix. The muscular wall of the uterus is called the myometrium and the inner lining the endometrium. The uterine tubes (Fallopian tubes) serve to deliver the ova to the uterus are attached to the superior angles of the uterus. The blood supply to the uterus is from the uterine and ovarian arteries.
95. utricle
Author: Mirrored from
Jim Croft's Flora of
Australia
Definition:
A small bladder; a membranous bladder-like sac enclosing an ovary or fruit.
96. Uukuvirus
Definition:
A genus of viruses in Bunyaviridae that are spread by ticks to a wide range of vertebrate hosts (mainly birds and rodents).
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