Nucleotides are the basic building blocks of nucleic acids. They consist of a nitrogenous base (adenine, guanine, thymine, cytosine in DNA; adenine, guanine, uracil, cytosine in RNA), a phosphate group, and a sugar (deoxyribose in DNA; ribose in RNA). The nitrogenous bases are either purines (adenine and guanine) or pyrimidines (cytosine and thymine). These bases are attached to the pentose sugar via a glycosidic bond. Phosphodiester bonds link the 3' carbon of one sugar to the 5' carbon of the next, forming the backbone of nucleic acid strands. Nucleotides

1. STRUCTURE OF
NUCLEOTIDES
MALAIKA QAMAR
BINF211101033

2. WHAT IS NUCLEOTIDES
• Ncleotide are tha basic building blocks of nuclic acid
• Molecule consisting of a nitrogen-containing base
• (adenine, guanine, thymine, or cytosine in DNA;
• adenine, guanine, uracil, or cytosine in RNA),
• a phosphate group, and a sugar (deoxyribose in DNA; ribose in RNA).

3. NITROGENOUS BASES
• Nitrogenous bases present in the DNA can be grouped into two categories:
• purines (Adenine (A) and Guanine (G)),
• pyrimidine (Cytosine (C) and Thymine (T)).
• These nitrogenous bases are attached deoxyribose through a glycosidic bond.

4. PENTOSE SUGAR
• The pentose sugar in DNA is called deoxyribose,and in RNA, the sugar is ribose.
• The difference between the sugars is the presence of the hydroxyl group on the 2’
carbon of the ribose and its absence on the 2’ carbon of the deoxyribose.

5. PHOSPHODIESTER BOND
• Phosphodiester bond occurs when two of the hydroxyl groups in phosphoric acid
react with hydroxyl groups on other molecules to form two ester bonds.
• Phosphodiester bonds are central to all life on Earth,[fn 1] as they make up the
backbone of the strands of nucleic acid. In DNA and RNA
• the phosphodiester bond is the linkage between the 3’ carbon atom of one sugar
molecule and the 5’ carbon atom of another, deoxyribose in DNA and ribose in
RNA.
• Strong covalent bonds form between the phosphate group and two 5-carbon
ring carbohydrates (pentoses) over two ester bonds

6. EFFECTS OF NUCLEOTIDES
• Nucleotides are substances which are synthesised endogenously
they have important effects on the growth
development of cells which have a rapid turnover, such as those in the immune system
and the gastrointestinal tract.
The intestinal epithelium is a rapidly proliferating tissue with a high cellular turnover
rate
A complete cell cycle in humans is 24 hours, with a replacement of the entire enteric
epithelium within 3–6 days
. In healthy people, dietary nucleotides are probably not essential, and in fact most will
be metabolised and rapidly excreted from the system