DNA: Difference between revisions
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DNA is found in the nucleus of a cell where it is packaged into a compact form called a chromosome with the help of several proteins known as histones. It is also found in cell structures called mitochondria. However in case of prokaryotes DNA is not enclosed in a nucleus or a membrane but is present in the cytoplasm. The DNA in prokaryotes in generally circular and supercoiled without any histones. DNA stores genetic information as a sequence of nucleotides in special regions known as genes which are used to make proteins. The expression of genetic information into proteins is a two-stage process wherein the sequence of nucleotides in DNA is converted to a molecule called Ribonucleic acid or [[RNA]] by a process called [[transcription]]. RNA is used to make proteins by another process called [[translation]]. The human genome contains nearly 3 · 10<sup>9</sup> bases with around 20,000 genes on 23 chromosomes. <ref name='gene'>http://www.genome.gov/25520880 </ref> | DNA is found in the nucleus of a cell where it is packaged into a compact form called a chromosome with the help of several proteins known as histones. It is also found in cell structures called mitochondria. However in case of prokaryotes DNA is not enclosed in a nucleus or a membrane but is present in the cytoplasm. The DNA in prokaryotes in generally circular and supercoiled without any histones. DNA stores genetic information as a sequence of nucleotides in special regions known as genes which are used to make proteins. The expression of genetic information into proteins is a two-stage process wherein the sequence of nucleotides in DNA is converted to a molecule called Ribonucleic acid or [[RNA]] by a process called [[transcription]]. RNA is used to make proteins by another process called [[translation]]. The human genome contains nearly 3 · 10<sup>9</sup> bases with around 20,000 genes on 23 chromosomes. <ref name='gene'>http://www.genome.gov/25520880 </ref> | ||
DNA was first discovered by the German biochemist Frederich Miescher in the year 1869.<ref>PMID: 17901982</ref> Based on the works of Erwin Chargaff, James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin, the structure of DNA was discovered in the year 1953. The structure of DNA is a <scene name='DNA/B-dna/15'>double helix</scene>: two complementary strands of polynucleotides that run in opposite directions and are held together by hydrogen bonds between them. This structure helps the DNA replicate itself during cell division and also for a single strand to serve as template during transcription. <ref name='gene'>http://www.genome.gov/25520880 </ref> | DNA was first discovered by the German biochemist Frederich Miescher in the year 1869.<ref>PMID: 17901982</ref> Based on the works of Erwin Chargaff, James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin, the structure of DNA was discovered in the year 1953. The structure of DNA is a <scene name='DNA/B-dna/15'>double helix</scene>: two complementary strands of polynucleotides that run in opposite directions and are held together by hydrogen bonds between them.<ref name='structure'>A Structure for Deoxyribose Nucleic Acid | ||
Watson J.D. and Crick F.H.C. | |||
Nature 171, 737-738 (1953)</ref> This structure helps the DNA replicate itself during cell division and also for a single strand to serve as template during transcription. <ref name='gene'>http://www.genome.gov/25520880 </ref> | |||
<scene name='DNA/B-dna/7'>Restore View</scene> | <scene name='DNA/B-dna/7'>Restore View</scene> | ||
