Search results
Results From The WOW.Com Content Network
The non-intron sequences that become joined by this RNA processing to form the mature RNA are called exons. [3] Introns are found in the genes of most eukaryotes and many eukaryotic viruses, and they can be located in both protein-coding genes and genes that function as RNA (noncoding genes). There are four main types of introns: tRNA introns ...
Although DNA is a double-stranded molecule, typically only one of the strands encodes information that the RNA polymerase reads to produce protein-coding mRNA or non-coding RNA. This 'sense' or 'coding' strand, runs in the 5' to 3' direction where the numbers refer to the carbon atoms of the backbone's ribose sugar.
Unlike double-stranded DNA, RNA is usually a single-stranded molecule (ssRNA) [4] in many of its biological roles and consists of much shorter chains of nucleotides. [5] However, double-stranded RNA (dsRNA) can form and (moreover) a single RNA molecule can, by complementary base pairing, form intrastrand double helixes, as in tRNA.
An open reading frame (ORF) is a reading frame that has the potential to be transcribed into RNA and translated into protein. It requires a continuous sequence of DNA which may include a start codon, through a subsequent region which has a length that is a multiple of 3 nucleotides, to a stop codon in the same reading frame.
The RNA that results from RNA splicing is a sequence of exons. The reason why introns are not considered untranslated regions is that the introns are spliced out in the process of RNA splicing. The introns are not included in the mature mRNA molecule that will undergo translation and are thus considered non-protein-coding RNA.
The word intron is derived from the terms intragenic region, [1] and intracistron, [2] that is, a segment of DNA that is located between two exons of a gene.The term intron refers to both the DNA sequence within a gene and the corresponding sequence in the unprocessed RNA transcript.
Double-stranded RNA forms an A-type helical structure, unlike the common B-type conformation taken by double-stranded DNA molecules. The secondary structure of RNA consists of a single polynucleotide. Base pairing in RNA occurs when RNA folds between complementarity regions. Both single- and double-stranded regions are often found in RNA molecules.
Since DNA is interpreted in groups of three nucleotides (codons), a DNA strand has three distinct reading frames. [15] The double helix of a DNA molecule has two anti-parallel strands; with the two strands having three reading frames each, there are six possible frame translations. [15] Example of a six-frame translation.