DNA has a double helix structure (discovered in 1953 by James Dewey Watson, Francis Crick et al.).
DNA is a polymer of deoxyribonucleic bases, more commonly called nucleotides. Each nucleotide consists of a phosphate group (or phosphoric acid) bonded to a sugar, deoxyribose, itself linked to a nitrogenous base. These bases are four in number: adenine (denoted A), thymine (denoted T), cytosine (denoted C) and guanine (denoted G). The backbone of the DNA is formed by the sugar-phosphate repetition.
Facilitated diffusion pumps polar and charged molecules, such as carbohydrates, amino acids, nucleosides, and ions, cross the plasma membrane.
As sodium ion concentrations build outside the plasma membrane because of the action of the primary active transport process, an electrochemical gradient is created
