The DNA molecule consists of three parts *nitrogenous base *deoxyribose sugar and *phosphate group.
The nitrogenous bases are nothing but cyclic carbon molecules that may or may not contain nitrogen groups attached to it. They are divided into two types :purines and pyrimidines.the purine consists of the adenine and guanine bases whereas the pyrimidines consists of the thymine and cytosine.the nitrogenous bases are attached to sugar molecule.the sugar molecule is pentose in structure.it is called the deoxyribose as it is nothing but the ribose sugar that lacks the oxygen molecule in its 2' position.the 5' carbon is attached to the phosphate group .the phosphate is a pentavalent compound with a double bonded oxygen and three single bond hydroxyl molecules
The structure of DNA was first described in 1953 by James Watson and Francis Crick. That is why a common double helical representation of the DNA is referred to as the Watson and Crick model. The DNA molecule is a double stranded helix that curls around a middle axis. The two helices are joined by hydrogen bonds.
The monomers that make up a DNA molecule are known as nucleotides. Each nucleotide contains one nitrogenous base (purines or pyrimidines). The purines include adenine and guanine and pyrimidines include cytosine and thymine (replaced by uracil in RNA). Besides the bases, each nucleotide has a phosphate group attached to it as well as a sugar group (ribose). Joined together, these make one nucleotide.
Complementary nucleotides line up next to each other (Adenine with thymine and guanine with cytosine). Once they have positioned themselves, hydrogen bonds are formed between them that 'zip' the two strands together. Adenine and thymine have 2 hydrogen bonds between them and guanine and cytosine have 3. The backbone of DNA is made from the sugar phosphate groups and nucleotides determine the sequence of genetic code.
About 10 nucleotide pairs fit into one helical turn and one helical turn is about 3.4nm.
The DNA molecule is made up of two long polymers connected by the bonding of hydrogen atoms and coiled in the shape of double helix. Each of the two polymers contains many structures which are called nucleotides, which, in turn, are further broken down into three parts: Deoxyribose, a phosphate group, and a nitrogenous base.
The three main parts that are in the DNA molecule are nitrogen for base, sugar and phosphate
DNA stands for Deoxyribonucleic Acid. It is basically a nucleic acid which contains genetic instructions that are used in development and functioning of every living being and even some viruses. DNA is responsible for storing information for long term.
The structure of DNA was first described by James Watson and Francis Crick in the year 1953. It is characterized by a right handed double helix that has 10 nucleotide pairs per helical turn. Each of the spiral strands is composed of sugar phosphate and attached bases. Each of these strands are connected to a complementary strand through hydrogen bonding between each of the paired bases. The structure is such that adenine pairs up with Thymine and guanine pairs up with cytosine.
DNA contains the following:
Ribose, a sugar
A phosphate group (a phosphorous atom surrounded by oxygen atoms)
Nitrogenous bases: Adenine, guanine, thymine, and cytosine (often abbreviated as A, G, T, C)
Ribose molecules and phosphate groups combine to form the sugar-phosphate backbone, which are the two long "strands" of DNA that hold the nitrogenous bases
DNA contains about two genes which coil round each other.