A nucleotide is the basic building block of nucleic acids, such as DNA and RNA. Each nucleotide is composed of three main parts:
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Phosphate Group: This is a phosphorus atom bonded to four oxygen atoms. In a nucleotide, it is typically attached to the 5' carbon of the sugar. The phosphate group plays a crucial role in linking nucleotides together to form the backbone of the nucleic acid strand.
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Sugar: The sugar in a nucleotide can be either ribose (in RNA) or deoxyribose (in DNA). The sugar molecule is a five-carbon sugar that forms the central part of the nucleotide structure.
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Nitrogenous Base: This is a nitrogen-containing molecule that can be one of five different bases: adenine (A), thymine (T), cytosine (C), and guanine (G) in DNA; and adenine (A), uracil (U), cytosine (C), and guanine (G) in RNA. The specific nitrogenous base determines the genetic information carried by that nucleotide.
Together, these three components form a nucleotide, which can then link with other nucleotides to create long chains that make up DNA and RNA molecules.