1. Nitrogenous Base: This is a nitrogen-containing molecule that can be one of four types:
* Adenine (A) and Guanine (G) are purines, which have a double-ring structure.
* Cytosine (C) and Thymine (T) are pyrimidines, which have a single-ring structure.
* Uracil (U) is a pyrimidine found in RNA, replacing Thymine.
2. Pentose Sugar: This is a five-carbon sugar that can be either deoxyribose (in DNA) or ribose (in RNA).
3. Phosphate Group: This is a molecule composed of phosphorus and oxygen. It is attached to the 5' carbon of the sugar.
How these parts are connected:
* The nitrogenous base is attached to the 1' carbon of the sugar.
* The phosphate group is attached to the 5' carbon of the sugar.
Connecting nucleotides:
* Nucleotides are linked together to form a polynucleotide chain.
* The phosphate group of one nucleotide attaches to the 3' carbon of the sugar of the next nucleotide, forming a phosphodiester bond.
* This creates a sugar-phosphate backbone with the nitrogenous bases extending outward.
Function:
* The sequence of nitrogenous bases in a polynucleotide chain carries genetic information.
* The phosphate groups give DNA and RNA their acidic properties.
* Nucleotides are also involved in other cellular processes, such as energy transfer (ATP) and signal transduction.
