Some regulatory proteins affect the transcription of multiple genes. This occurs because multiple copies of the regulatory protein binding sites exist within the genome of a cell.

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(1) Cells contain DNA that controls the production of proteins. (2) DNA is composed of proteins that carry coded information for how cells function. (3) Proteins are used to produce cells that link amino acids together into DNA. (4) Cells are linked together by proteins to make different kinds of DNA molecules.

The traits of a living thing depend on the complex mixture of interacting components inside it. Proteins do much of the chemical work inside cells, so they largely determine what those traits are. But those proteins owe their existence to the DNA (deoxyribonucleic acid), so that is where we must look for the answer.

During transcription, the DNA of a gene serves as a template for complementary base-pairing, and an enzyme called RNA polymerase II catalyzes the formation of a pre-mRNA molecule, which is then processed to form mature mRNA (Figure 1).

A gene is a length of DNA that codes for a specific protein. So, for example, one gene will code for the protein insulin, which is important role in helping your body to control the amount of sugar in your blood. Genes are the basic unit of genetics.

Attached to each sugar is one of four bases–adenine (A), cytosine (C), guanine (G), or thymine (T). The two strands are held together by hydrogen bonds between the bases, with adenine forming a base pair with thymine, and cytosine forming a base pair with guanine.

It is formed by combining four parts: A, C, G and T (adenine, cytosine, guanine and thymine), called bases of DNA combine in thousands of possible sequences to provide the genetic variability that enables the wealth of aspects and functions of living beings.

The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people.

In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.

Dictated by specific hydrogen bonding patterns, “Watson–Crick” base pairs (guanine–cytosine and adenine–thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence.

Base-pairing is formed through hydrogen bonds between nucleo-bases of the corresponding nucleotides. Hydrogen bonds can be formed if Bi and Bj fall within interaction range.

Base stacking. Base stacking is a common arrangement of nucleobases found in the three dimensional structure of nucleic acids. Bases (or base pairs) are planar, and these planes stack at contact distance (about 3.4 Angstrom), excluding water and maximizing Van der Waals interactions.

The two primary modes of secondary structure formation in nucleic acids are Watson-Crick basepairing and base-stacking. Certain sequences of nucleotides, particularly tracts of adenines, are known to exhibit strong stacking tendencies in single-stranded nucleic acids in the absence of a complementary strand (5).