The key difference between nucleotide and base is that the nucleotide is a nitrogenous base that makes up the structure of nucleic acid whereas a base is any compound having a releasable hydroxide ion or a lone electron pair or a compound that can accept protons.
The base of nucleotide has basic characteristics due to the lone pairs of nitrogen. Here, a base doesn’t imply the usual bases we come across in chemistry, but these are special molecules present in biological systems with basic properties.
CONTENTS
1. Overview and Key Difference
2. What is Nucleotide
3. What is Base
4. Side by Side Comparison – Nucleotide vs Base in Tabular Form
5. Summary
What is Nucleotide?
The nucleotide is the building block of two important macromolecules (nucleic acids) in the living organisms; that is, the DNA and RNA. Hence, they are the genetic material of an organism and are responsible for passing genetic characteristics from generation to generation.
Furthermore, they are important to control and maintain cellular functions. Other than these two macromolecules, there are other important nucleotides. For example, ATP (Adenosine tri phosphate) and GTP are important for energy storage. NADP and FAD are nucleotides, which act as cofactors. Nucleotides like CAM (cyclic adenosine monophosphate) are essential for ATP cell signaling pathways.
Figure 01: Structure of Nucleotides
Moreover, a nucleotide contains three units; a pentose sugar molecule, a nitrogenous base, and the phosphate group/s. According to the type of pentose sugar molecule, nitrogenous base, and the number of phosphate groups, nucleotides differ. For instance, in DNA, there is a deoxyribose sugar, and in RNA, there is a ribose sugar. There, the phosphate group of one nucleotide links with the –OH group of carbon 5 of the sugar to form these macromolecules. Normally, in the nucleotides of DNA and RNA, there is one phosphate group. However, in ATP, there are three phosphate groups. The linkages between phosphate groups are high energy bonds. Accordingly, there are eight types of nucleotides in DNA and RNA.
Below eight nucleotides are the basic types.
- Deoxyadenosine monophosphate
- Deoxycytidine monophosphate
- Deoxyguanosine monophosphate
- Deoxythymidine monophosphate
- Adenosine monophosphate
- Cytidine monophosphate
- Guanosine monophosphate
- Uridine monophosphate
Moreover, the other nucleotides are derivatives of these. Nucleotides may link with each other to form a polymer. This linkage occurs between the phosphate group of a nucleotide with a hydroxyl group of the sugar. Hence, by making this kind of phosphodiester bonds, macromolecules like DNA and RNA forms.
What is Base?
A base is a compound that has a releasable hydroxide ion or a lone electron pair or a compound that can accept protons. Therefore, there are different definitions for a base according to different scientists. Bronsted- Lowry defines a base as a substance that can accept a proton. According to Lewis, any electron donor is a base. According to the Arrhenius definition, a compound should have a hydroxide anion and the ability to donate it as a hydroxide ion to be a base. However, according to Lewis and Bronsted- Lowry, there can be molecules, which don’t possess hydroxides but can act as a base. For instance, NH3 is a Lewis base, because it can donate the electron pair on nitrogen.
Figure 02: Acids differ from Bases; Bases form Hydroxide Ions upon Dissociation at Aqueous Solutions
Further, the characteristic features of a base are a slippery soap like feeling and a bitter taste. These compounds can react with acids to neutralize them. There are two major forms of bases as strong and weak bases. Strong bases are those that can completely ionize in an aqueous solution while a weak base is a compound that partially ionizes.
What is the Difference Between Nucleotide and Base?
Nucleotides and bases are two different compounds, but they are related as well because nucleotides contain a nitrogenous base. The nitrogenous base is a part of a nucleotide. Therefore, the key difference between nucleotide and base is that nucleotide is a nitrogenous base that makes up the structure of nucleic acid whereas a base is any compound having a releasable hydroxide ion or accept a proton or donate a lone electron pair.
Moreover, the nitrogenous base in the nucleotide is a heterocyclic ring containing nitrogen. Other than this, in a nucleotide, there is a pentose sugar and a phosphate group too. However, Base is the most important and functional unit of nucleotides in DNA or RNA. The below infographic on the difference between nucleotide and base describes these differences in more detail.
Summary – Nucleotide vs Base
Nucleotides and bases are two different compounds. However, nucleotides also have a part that is a base. The key difference between nucleotide and base is that the nucleotide is a nitrogenous base that makes up the structure of nucleic acid whereas a base is any compound that has a releasable hydroxide ion or a lone electron pair or a compound that can accept protons.
Reference:
1. Britannica, The Editors of Encyclopaedia. “Nucleotide.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 17 July 2008. Available here
Image Courtesy:
1.”0322 DNA Nucleotides”By OpenStax (CC BY 4.0) via Commons Wikimedia
2.”215 Acids and Bases-01″By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013., (CC BY 3.0) via Commons Wikimedia
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