What are the building blocks for nucleic acids DNA and RNA?
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are polymers of nucleotides linked in a chain through phosphodiester bonds. In biological systems, they serve as information-carrying molecules or, in the case of some RNA molecules, catalysts. This brief review will focus on aspects of structure of particular importance in manipulating DNA.
Nucleotides are the building blocks of all nucleic acids.
Well, there are four different nucleotides that make up DNA and RNA: adenine (A), cytosine (C), guanine (G), and thymine (T) for DNA, and uracil (U) for RNA. It's like a genetic alphabet soup! Just remember, when it comes to nucleic acids, the letters A, C, G, T, and U are the real MVPs.
Each nucleotide is composed of three main components: a sugar molecule, a phosphate group, and a nitrogenous base.
1. Sugar molecule: DNA contains deoxyribose, while RNA contains ribose. The sugar molecule forms the backbone of the nucleic acid chain and provides stability.
2. Phosphate group: The phosphate group is attached to the 5' carbon of the sugar molecule. It links nucleotides together through phosphodiester bonds, creating a polynucleotide chain.
3. Nitrogenous base: There are four types of nitrogenous bases found in DNA and RNA: adenine (A), cytosine (C), guanine (G), and thymine (T) found in DNA or uracil (U) in RNA. The nitrogenous bases are attached to the 1' carbon of the sugar molecule and determine the genetic code.
In DNA, the base pairs are formed between adenine (A) and thymine (T) and between cytosine (C) and guanine (G). In RNA, the base pairs are formed between adenine (A) and uracil (U), as there is no thymine present.
These building blocks of nucleic acids play a crucial role in storing and transmitting genetic information in living organisms.
To understand the building blocks of DNA and RNA, we need to look at the structure of a nucleotide. A nucleotide is composed of three main parts:
1. Sugar: Both DNA and RNA contain a sugar molecule, but the sugar differs between the two. DNA contains deoxyribose sugar, while RNA contains ribose sugar. The sugar provides the backbone of the nucleic acid chain.
2. Phosphate Group: A nucleotide also has a phosphate group attached to the sugar molecule. The phosphate group links adjacent nucleotides together through phosphodiester bonds, forming the sugar-phosphate backbone of the DNA or RNA strand.
3. Nitrogenous Base: The third component of a nucleotide is a nitrogenous base. There are four different nitrogenous bases found in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). In RNA, uracil (U) replaces thymine as one of the nitrogenous bases. The nitrogenous base is responsible for carrying the genetic information in the nucleic acid molecule.
The combination of the sugar, phosphate group, and nitrogenous base make up a nucleotide. These nucleotides link together in a specific sequence to form the DNA or RNA molecule. The specific sequence of nucleotides determines the genetic code and is responsible for the unique characteristics of an organism.