What are the components of a nucleotide

What are the components of a nucleotide and which component varies from one nucleotide to another in DNA and RNA?
What governs the pattern of DNA base pairing in DNA and RNA? Pick one of these questions to discuss. 2. What are the different types of RNA? Pick one type and discuss its function. 3. Discuss one of the events that occur during protein processing and secretion. 4. Discuss the consequences of DNA replication errors and provide a specific example. 5. Pick one specific stage of the cell cycle and discuss the events that occur during that stage and how it can be identified under a microscope. 6. Explain how the timing of cell division is regulated.