The Same DNA (deoxyribonucleic acid)

DNA from all organisms is made up of the same chemical and physical components. DNA molecules are shaped like a twisted ladder (“double helix”). Each rung/step is made up of a Base pair of nucleotide (molecules) bases, either A (Adenine) and T (Thymine) or C (Cytosine) and G (Guanine)). These Base pairs are held together by a band of Sugar phosphate on either end. The DNA sequence is a particular side-by-side arrangement of bases (half of the ladder) along the DNA strand (e.g., ATTCCGGA). The genome is an organism’s complete set of DNA. DNA in the human genome is arranged into 24 distinct chromosomes. Genes comprise only about 2% of the human genome.

Photo Credit: 
U.S. Department of Energy Genome Programs (http://genomicscience.energy.gov)