Alpha helix
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Double helix
(Science: molecular biology) conformation or shape that two linear strands of dna assume when bonded together and become twisted into a helix.
Double Helix
Double helix is the description of the structure of a DNA molecule. A DNA molecule consists of two strands that wind around each other like a twisted ladder.
The term Double helix (plural helices) describes the structure of DNA as first published by James Watson and Francis Crick in 1953.
The helix can be virtually any length; when fully stretched, some DNA molecules are as much as 5 cm (2 inches!) long.
This helical, usually right-handed arrangement of a polypeptide chain is a common secondary structure in proteins. The helix has maximal intra-chain hydrogen bonding.
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Helix Directory Lists Testing Laboratories
Since August 1993, Helix: A Directory of Medical Genetics Laboratories has been fulfilling clinician requests for names of laboratories that perform molecular genetic testing.
Helix-turn-helix A recurring motif found in many DNA-binding proteins, in which two α-helical segments are linked by a short hairpin turn; the two segments are 34 Å apart, which allows them to fit into adjoining major grooves in DNA.
a-helix: Common secondary 3-dimensional structure of proteins in which the linear sequence of amino acids is folded into a spiral that is stabilized by hydrogen bonds between the carboxyl oxygen of each peptide bond.
alpha helix
A spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure.
alternation of generations ...
Double helix: The twisted-ladder shape that two linear strands of DNA assume when complementary nucleotides on opposing strands bond together.
Double helix. Describes the coiling of the antiparallel strands of the DNA molecule, resembling a spiral staircase in which the paired bases form the steps and the sugar-phosphate backbones form the rails.
Double helix
The structural arrangement of DNA, which looks something like an immensely long ladder twisted into a helix, or coil.
helix- A secondary structural motif of proteins in which a linear sequence of amino acids folds into a right-handed helix stabilized by internal hydrogen bonding between backbone atoms.
alpha-helix Literally the first spiral arrangement of the genetic DNA molecule; regular coiled arrangement of polypeptide chain in proteins; secondary structure of proteins.
Double helix
The shape that two linear strands of DNA assume when bonded together.
Related Terms:
Deoxyribonucleic acid (DNA) ...
Double helix
- A term used to describe the configuration of a DNA molecule. The helix consists of two spiraling strands of nucleotides held together with chemical bonds.
DNA double helix - the structure of our genetic material; human DNA consists of two complementary strands which twist around each other like two spiral staircases.
The strands are twisted forming a configuration that is often referred to as a double helix. The photograph below is of a model of DNA.
Complimentary base pairing ...
DNA is a double helix, with bases to the center (like rungs on a ladder) and sugar-phosphate units along the sides of the helix (like the sides of a twisted ladder).
The combination of domains in a single protein determines its overall function.
Double helix The shape that two linear strands of DNA assume when bonded together.
Duplication Duplication of a sequnece of DNA or section of chromosome.
The normal form of DNA found in biological systems, which exists as a right-handed helix. beta-Lactamase. Ampicillin resistance gene. (See Selectable marker.) Bacillus. A rod-shaped bacterium. Bacillus thuringiensis (Bt).
base pair a pair of hydrogen-bonded nitrogenous bases (one purine and one pyrimidine) that join the component strands of the DNA double helix.
DNA - deoxyribonucleic acid is the double-helix molecule holding the genetic information of organisms that, along with protein, composes the chromatin ...
The prominent rim of the auricula is called the helix; where the helix turns downward behind, a small tubercle, the auricular tubercle of Darwin, is frequently seen; ...
These bonds, which bind the complementary strands of DNA together in a double helix, are broken at elevated temperatures (about 95° C). Each single-stranded piece of DNA (ssDNA) is then built upon to form a new, double-stranded molecule (dsDNA).
Is DNA a right- or left-handed helix?
Grooves in the DNA double helix.
The deoxyribose sugar ring.
Is the deoxyribose ring flat or puckered?
Location of the sugar in the DNA double helix.
Are the two strands of DNA parallel or anti-parallel?
Computer Model of the DNA Helix
Despite what you may have seen in some textbooks, DNA is not built like a twisted ladder. The helix, or spiral, is an inherent feature of the DNA molecule.
The double stranded DNA helix is like a twisted ladder. The sides of the ladder are repeating sugar-phosphate and the rungs of the ladder are the bases, A, T, C, G. The rungs always are A matched to T and C matched to G.
The animal kingdom is unique among eukaryotic organisms because most animal tissues are bound together in an extracellular matrix by a triple helix of protein known as collagen.
Proteins that unwind the DNA double helix.
Hemimethylation
Double stranded DNA in which only one strand is methylated at a particular site. For example, at GATC sites in E.
deoxyribonucleic acid (DNA) A nucleic acid composed of two polynucleotide strands wound around a central axis to form a double helix; the repository of genetic information.
DNA is composed of two anti-parallel strands which wind about a common axis to form a double helix.
They are antiparallel which is essential for gene coding and replication
DNA molecule has 2 separate chains of nucleotides hold together by base pairing / DNA normally twist into a helix (coil) / forms a double helix ...
DNA replication unwinds a portion of the DNA helix, forming a fork like structure.
Other Resources
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alpha helix, beta sheet, random coil); local structure within an RNA molecule which is conferred by base pairing of nucleotides which are relatively closely positioned within the sequence (e.g., hairpins, stem-loop structures).
Two nitrogenous (purine or pyrimidine) bases (adenine and thymine or guanine and cytosine) held together by weak hydrogen bonds. Two strands of DNA are held together in the shape of a double helix by the bonds between base pairs.
Complementary (As in complementary strand) having the sequence of nucleotides which will form a base paired double helix with another strand of DNA or RNA.
Complementary DNA see cDNA ...
Leucine zipper: A motif found in certain proteins in which Leu residues are evenly spaced through an a-helical region, such that they would end up on the same face of the helix. Dimers can form between two such proteins.
Domi nant gene: A gene which, when present on a chromosome, passes on a certain physical characteristic, thereby dominating over a recessive gene present on another chromosome. Double helix: A common name for DNA; ...
 See also: DNA, Trans, Protein, Molecule, Organ
  
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