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The chromosomes in the nucleus of a cell contain all the information a cell needs to carry on its life processes. They are made up of a complex chemical (a nucleic acid) called deoxyribonucleic acid, or DNA for short. Scientist's decoding of the chemical structure of DNA has led to a simple conceptual understanding of genetic processes. DNA is the hereditary material of all cells. It is a double-stranded helical macromolecule consisting of nucleotide monomers with deoxyribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T). In the chromosomes of a cell, DNA occurs as fine, spirally coiled threads that in turn coils around another, like a twisted ladder. The DNA molecule is threaded so fine that it is only possible to see it under high powerful electron microscopes. To get a sense of exactly how long an uncoiled DNA molecule is compared to a typical cell, a cell is magnified 1000 times. At this scale, the total length of all the DNA in the cell's nucleus would be 3 km — the equivalent distance of the Lincoln Memorial to the capital in Washington, DC. The human genome comprises the information contained in one set of human chromosomes which themselves contain about 3 billion base pairs (bp) of DNA in 46 chromosomes (22 autosome pairs 2 sex chromosomes). The total length of DNA present in one adult human is calculated by the multiplication of (length of 1 bp)(number of bp per cell)(number of cells in the body) ( × 10-9 m)(6 × 109)(1013) 2.0 × 1013 meters That is the equivalent of nearly 70 trips from the earth to the sun and back. 2.0 × 1013 meters = astronomical units / 2 = round trips to the sun On the average, a single human chromosome consists of DNA Molecule that is almost 5 centimeters. #codons #Morphogenesis #RNA #Transcription #Genotype #TurnerSyndrome #nucleicAcid #molecularBiology #Promoter #Alleles #GeneExpression #TumorCells #macromolecule #Chromosome #uncoiledDNA #Phenotype #DNA #Genes #chromosomes #gene #genome #Iherb #GeneticsLecture #cytoplasm #Genetics #Rrna #Nucleotide #GeneticTesting #GeneticCode #nucleus #eukaryotic
