Structure of DNA and RNA

DNA and RNA are two components of organisms that play a significant role. They are contained in the nucleus, which is the center of all cellular activity. While DNA and RNA sound similar, they display different structures and carry out distinct roles. Today we will learn about the structures of DNA and RNA.

 

Structure of RNA (left) and DNA (right)

 

Similarities and Differences between RNA and DNA

The basic structures of both DNA and RNA are called nucleotides, which are constituted of a phosphate group, a pentose sugar, and a base. Whereas the sugar molecule in DNA is called a deoxyribose sugar, it is called a ribose sugar in RNA molecules. Another difference is related to the type of nitrogenous bases. Both RNA and DNA have bases of guanine (G), adenine (A), and cytosine (C), but DNA has thymine (T) while RNA has uracil (U). These four bases can be classified into either purines or pyrimidines according to the number of rings they have in their structure. Adenine and guanine are examples of purines that have two rings, and thymine, cytosine, and uracil are examples of pyrimidines that have four rings.

Furthermore, DNA forms a double helix through hydrogen bonds; on the contrary, RNA forms only a single strand. To summarize the overall difference between RNA and DNA, DNA contains sugar deoxyribose while RNA contains sugar ribose; DNA has bases adenine, thymine, guanine, and cytosine while RNA has bases adenine, uracil, guanine, and cytosine; DNA is double stranded while RNA is single stranded. The double helix form of DNA will be discussed further in the next paragraph.

Double Helix Structure of DNA

 

Antiparallel Structure of DNA

In DNA, nitrogenous bases do not pair in any way – they have a structure. Guanine and cytosine are always pairs, and adenine and thymine are also pairs. The two strands of DNA are put together with hydrogen bonds that form between guanine and cytosine or adenine and thymine. There are three hydrogen bonds between G and C, and there are two hydrogen bonds between A and T. The two strands are antiparallel to one another since they must face each other for bases to pair.

 

Scientists Related To Discovering DNA Structure

Watson and Crick were two scientists who built a model of DNA structure based on evidence gathered by other scientists. They concluded the double helix structure through photos taken by Rosalind Franklin and Maurice Wilkins. They also utilized Chargaff’s base ratio (A:T = 1:1, C:G = 1:1). Through these data, they created a 1.8m model with metal, enabling the visualization of DNA.

Works Cited

Helmenstine, Anne Marie, and Helmenstine. “Do You Know the Differences Between DNA and RNA?” Thoughtco., Dotdash, http://www.thoughtco.com/dna-versus-rna-608191.