form

Zygotene

...apsis , or pairing, of homologous chromosomes to form a bivalent . Full article >>> Zygotene The term proposed by Gregoire (1907) to describe the nuclei at a particular stage of prophase 1 of meiosis when the homologous chromosomes are associating side by side. (Gk. zygon, yoke; ...

Zygote

...apsis , or pairing, of homologous chromosomes to form a bivalent . Full article >>> A z... cells that unite during sexual reproduction to form a diploid zygote . Male gametes are sperm and female gametes are eggs. Full article >&...

Z-DNA

...>>> Z-DNA : Alternative left-handed form of the double helix which retains Watson-Crick type base pair ing. Full article >>> (See b- DNA , c DNA , Complementary DNA or RNA , DNA polymorphism , DNA sequencing , Double- strand ed complementary DNA , Duplex DNA , Z-...

Yolk

... of four extraembryonic membranes of amniotes to form during embryo genesis. Like the allantois , it a...hial region Development of the body cavities The form of the embryo at different stages of its growth ... Full article >>> About 5000 nuc...

Xeroderma pigmentosum

...#62;> Mutation in this gene leads to one form of the disease syndrome xeroderma pigmentosum . Homologs of the XPF protein are present in fly, worm, plant , yeast and archea, indicating conservation of an essential function throughout all of evolution . Full article >>> A de...

Wild type

..... Full article >>> Wild type The form of an organ ism that occurs most frequently in nature. Working Draft DNA Sequence See: Draft DNA Sequence Return to Top ... Full article >>> wild type The normal (non-mutated) phenotype . wobble The relatively loose base pair ...

White blood cells

...ood cells (a.k.a. leukocytes ) are cells which form a component of the blood. They are produced in the bone marrow and help to defend the body against infectious disease and foreign materials as part of the immune system . Full article >>> White blood cells (also called leukocytes ...

Voluntary muscle

.... During contr action it combines with actin to form acto myosin . Full article >>> Spinocerebellar ataxia, type 1 (SCA1; in voluntary muscle movements, reflex disorders, explosive speech) Spinal muscular atrophy (SMA; severe, usually lethal progressive muscle -wasting dis order in...

Vitelline membrane

...ular cells that surround an oocyte and that will form the fertilization membrane if sperm penetration occurs. Full article >>> vitelline membrane The noncellular membrane that encloses the egg cell . Full article >>> vitelline membrane Delicate membrane that sur...

Viscera

...planchnic mesoderm and endoderm . It will later form part of the body wall in the embryo as well as the yolk sac and allantois . Full article >>> So intricate is the human body that only a small number of professional human anatomists, after years of patient observation, are com...

Vitamin

...nts the conversion of nitrates to a carcinogenic form called nitrosamines. Full article >>> vitamin An organ ic substance other than a carbohydrate , lipid , or protein that is needed for normal metabolism but cannot be synthesized in adequate amounts by the body. Full article &...

Virus

...sometimes with associated protein and RNA . The form of the genetic material in virus es and cells . Full article >>> Bacteriophage a type of virus that invades lives in and kills a host species of bacterium (phago = to eat) ... Full article >>> even after the...

Vesicle

... high mass accuracy and sensitivity Fourier trans form ion cyclotron resonance (FTICR) mass spectrometry...#62;> liposomes - synthetic bilayer in the form of a spherical vesicle membrane potential - voltage difference across a membrane due to a slight e...

Vessels

...;>> Masses of splanchnic mesoderm that form the first red blood cells and blood vessels . Found in the gut wall of amphibians and the yolk sac of amniotes. Full article >>> Recent studies indicate that endothelial dysfunction of peripheral and coronary resistance and cond...

Vertebrates

...rates , this innermost layer of cells goes on to form the linings of the gut ( esophagus , stomach , intestine s, rectum , colon ), pharyngeal pouch derivatives (tonsils,thyroid, thymus, parathyroid glands ), lungs , liver , gall bladder, pancreas . Full article >>> Genes for the ...

Ventral root

...al root s before uniting with the sensory axons to form the mixed nerves . Full article >>>...

Veins

...thin the mesophyll cells in C3 plant s, which form a dense layer on the upper surface of the leaf and a spongy layer on the lower surface. Bundle-sheath cells surrounding the veins are not photosynthetic. Full article >>>...

Vector

...ecule s that can be joined with DNA fragments to form recombinant DNA molecule s. veins Thin-walled vessels that carry blood to the heart . Units of the circulatory system that carry blood to the heart . Full article >>> Vector s Figure 3: Comparison of non-integrating plasmi...

Vectors

...ecule s that can be joined with DNA fragments to form recombinant DNA molecule s. veins Thin-walled vessels that carry blood to the heart . Units of the circulatory system that carry blood to the heart . Full article >>> Vectors Figure 3: Comparison of non-integrating plasmid ...

Vascular bundles

...dles are arranged within the stem of dicot s to form a cylinder, appearing as a ring of spots when you cut across the stem . Full article >>> pith ray The region or tissue located between vascular bundles in a stem and connecting the pith and cortex ; also termed interfascicu...

Vascular bundle

...dles are arranged within the stem of dicot s to form a cylinder, appearing as a ring of spots when you cut across the stem . Full article >>>...

Variety

...ble to a morphological variant or variant group, a form which is not typical but is not sufficiently recog...le s; functions are not fully understood, but some form parts of spliceosome s, active in RNA splicing . smooth ER ... Full article >>> c...

Variation

... Polymorphism The occurrence of more than one form of, for example, a DNA sequence , type of protein or morphological trait in a group of organ isms, revealing underlying genetic variation in the population . Full article >>>...

Vacuoles

...cuoles , but as the cells mature, these unite to form a large central vacuole . Vacuoles serve several functions, such as ... Full article >>> Vacuoles are membranous sacs similar to, but larger than vesicle s. Vacuoles store water and dissolved substances. They are more important...

Uric acid

... uric acid and other acids as rain. The acids form when sulfur dioxide and nitrogen oxides released d...c Organ isms which excrete excess nitrogen in the form of urea . uricotelic Organ isms which excrete excess nitrogen in the form of uric acid ... Full...

Urea cycle

...c Organ isms which excrete excess nitrogen in the form of urea . Full article >>> Most of these defects cause significant disability that cannot be treated satisfactorily by such other approaches as modifying the diet or supplying the enzyme . Some examples include adrenoleukodystrophy, ...

Uracil

...osphate atoms they contain). The five bases that form the nucleic acids are adenine (A), guanine (G), cytosine (C), tymine (T) and uracil (U). Full article >>>...

Urea

...>> urea [Gk. ouron, urine ] A soluble form of nitrogenous waste excreted by mammals and mos...c Organ isms which excrete excess nitrogen in the form of urea . Full article >>> In 1828, Friedrich Whler published a paper about the synt...

Unicellular

...e. Full article >>> A unicellular form of fungi . Some fungi (for example Saccharomyces cerevisiae ) are only known to reproduce as yeast while other fungi (for example, Candida albicans) are dimorphic, ... Full article >>> spherical unicellular organ ism Source: N...

Umbilical cord

...n birds and reptiles, it fuses with the chorion to form the chorioallantoic membrane which assists in respiration , and in addition it is the site of storage of nitrogenous wastes. In eutherian mammals , it forms the vessels of the umbilical cord and ... Full article >>>...

Tumor

...as independent cells , growing without control to form tumor s. Tumor s grow in a series of steps. The first step is hyperplasia, meaning that there are too many cells resulting from uncontrolled cell division . Full article >>> Tumor Suppressor BRCA1 is believed to act as a tum...

Tubulin

...lled tubulin . Tubulin dimer s are arranged to form a long hollow cylinder. The fibers are lengthened and shortened as tubulin dimer s assemble or disassemble from one or both ends of the filament. Full article >>> grow at each end by the polymerization of tubulin dimer s (power...

True-breeding

...ed shape in pea plant s exists in two forms, one form or allele for round seed shape (R) and the other for wrinkled seed shape (r). A true-breeding round seed plant would be (RR) for that trait and a true-breeding wrinkled ... Full article >>> True-breeding Homozygous fo...

Trophoblast

...fertilization ; projections from the trophoblast form vessels , which merge with maternal blood vessels to form the placenta . tropism : the bending or turning response of a plant caused by external stimuli. ...

Trans-splicing

...ll article >>> Trans-splicing is a form of splicing that joins two exons that are not within the same RNA transcript . [edit] Self-splicing ... Full article >>> 3' UTR 5' UTR Mature transcript Primary transcript Splicing cis- splicing polyA trans-splicing ...

Transposition

...;> Transposition al recombination Another form of site-specific recombination , transposition al recombination does not require an identical strand of DNA in the mobile element to match with the target DNA . Full article >>> Transposition in these cases occurs by a "copy...

Transmembrane proteins

...rane proteins that span the bilayer several times form a hydrophilic channel through which certain ions and molecule s can enter (or leave) the cell . [Example] Peripheral Membrane Proteins ... Full article >>> (Redirected from Transmembrane proteins ) A trans membrane protein is...

Transgenic plant

... trans ferred by this bacterium causes plant s to form a gall. Full article >>> Transgenic plant . Genetically engineered plant or offspring of genetically engineered plant s. The transgenic plant usually contains material from at least one unrelated organ isms, such as from a vi...

Transgenic

... trans ferred by this bacterium causes plant s to form a gall. Full article >>> transgenic : Containing genes from another species . ultrasound imaging: A technique for looking inside the body by using sound waves to create images. Full article >>> transgenic Cells or ...

Transformation

...r surroundings. The ability to deliberately trans form the bacterium E. Full article >>> ...s a means to learn about God, and so as the proper form of "theology". Full article >>> Finally, plant transformation in arabidopsis is...

Transfer RNA

...ticle >>> transfer RNA (t RNA ). A form of RNA of about 70 or 80 nucleotide s, which ar...e- base codon of the m RNA links to a specific form of transfer RNA (t RNA ) containing the complement ary three- base sequence . Full article >...

Transcription

...cell . trans ducer A receptor that converts one form of energy into another. Full article >>> transcription - process of RNA synthesis from DNA template . transcription factor - DNA binding protein that turns genes on or off (regulates the level of transcription ) by bind...

Transcriptase

...nscriptase An enzyme used by retrovirus es to form a complementary DNA sequence (c DNA ) from the...copied by a RNA polymerase or transcriptase to form m RNA , which is then trans lated into proteins by the host . Like the above method, RNA repli...

Transcript

...cell . trans ducer A receptor that converts one form of energy into another. Full article >>&#...The inclusion or exclusion of different exons to form different m RNA transcript s. (See RNA .) Amino acid . Any of 20 basic building blocks of prote...

Trans-

... article >>> Trans- splicing is a form of splicing that joins two exons that are not within the same RNA transcript . [edit] Self-splicing ... Full article >>> Trans- dimer synthesis A process which permits nucleotide s to be insert ed opposite a pyrimidine ...

Trans

... bases too Definition of trans cription : verb form = trans cribe ... Full article >>> ...#62; trans ducer A receptor that converts one form of energy into another. trans duction . Condition in which bacteria l DNA (and the genetic cha...

Tracheids

...ds Long , tapered cells with pitted walls that form a system of tubes in the xylem and carry water and solutes from the roots to the rest of the plant . One type of xylem cells . Full article >>> tracheids : the main conducting vessels of the xylem in most vascular plants ...

Trait

... Marker A genetic trait of which one allelic form is selected or screened for following recombinati...r muscular dystrophy -- the most common and severe form of muscular dystrophy; trans mitted as an X-linked trait . X-linked recessive . Full article ...

Tissue

...ught to them by the blood, or by which they trans form their cell protoplasm into simpler substances, ....dles are arranged within the stem of dicot s to form a cylinder, appearing as a ring of spots when you cut across the stem . Full article >>...

Thyroid gland

...s in the thyroid secrete thyroglobulin, a storage form of thyroid hormone . Full article >>> thyroid gland [Gk. thyra, a door] An endocrine gland that secretes iodine-containing hormones (T3 and T4), which stimulate metabolism and influence development and maturation in vertebrates...

Thylakoids

...hemicals are embedded. Collections of thylakoids form the grana . PICTURE ... Full article >>&...membrane in chloroplasts ; stacks of thylakoids form the grana . thylakoid The lamellar structure of the grana of chloroplasts . thymine A pyrim...

Thylakoid

...micals are embedded. Collections of thylakoid s form the grana . PICTURE ... Full article >>&...mbrane in chloroplasts ; stacks of thylakoid s form the grana . thylakoid The lamellar structure of the grana of chloroplasts . thymine A pyrim...

Thallus

... single egg (by mitosis ); anther idia, which form swimming sperm (again, by mitosis ). Full article >>>...

Tetrapod

...ds, and mammals . tetrathyridium Only metacestode form known in the tapeworm cyclophyllidean genus Mesocestoides. A large, solid-bodied cysticercoid. Full article >>> tetrapod Any vertebrate with two pairs of pentadactyl limbs. Ex. rats, frogs. Covered in Lab 15 Rat Muscular and Dige...

Tertiary Structure

...r tetrahydrobiopterin The fully reduced coenzyme form of biopterin. Full article >>> Thes..., and coils interact chemically with each other to form the unique three-dimensional shape of the protein , called the tertiary structure . Full article ...

Terminator region

...on of the DNA template , joins nucleotide s to form the synthesized strand of RNA and detaches from the template when it reaches the terminator region . PICTURE ... Full article >>> (See Codon .) Terminator region . A DNA sequence that signals the end of transcription . Tet...

Telophase

...l stage of mitosis , during which daughter nuclei form at the two poles of a cell . Telophase usually ...hromosomes gather at the poles of the cells and form a mass of chromatin ; the nuclear envelope develops, the nucleoli reappear, and the cells under...

Telomere

...tural distal end of a chromosome . Contain some form of simple repeating sequence , usually with a single strand ed distal end that may form a hairpin . Full article >>> Artificial chromosome A vector constructed from ho...

Syngamy

...f one gamete with another individual gamete to form a zygote , found in most animals with sexual r...al reproduction , together with syngamy . It is a form of nuclear division by which a diploid parent produces four haploid daughter cell s. Full ar...

Syncytium

...> After the 10th division the pole cells form at the posterior end of the embryo , segregating the germ line from the syncytium . Finally, after the 13th division cell membrane s slowly invaginate, dividing the syncytium into individual somatic cells . Full article >>>...