Nucleic Acid: Definition, Function, Structure, and Types - GeeksforGeeks (2023)

Based on what we've learned, nucleic acids are one of the most important types of macromolecules found in humans. They are the guardians of all the information about our genes that we pass on to future generations. Are we going to learn more about the strange structure of nucleic acids? Repetitive monomers are the building blocks of nucleic acids, as in all other types of biomolecules. These repetitive units, also called monomers, are known under the technical name of nucleotides. These are the components involved in the formation of nucleic acids. Nucleotides When we talk about the structure of nucleic acids, let's look at nucleotides. Nucleic acids are made up of smaller building blocks called nucleotides. A nucleotide can be broken down into parts called the "three essential building blocks". These three aspects are as follows:


This is usually five carbon sugars. that is, a pentose. These sugars attach to the phosphate groups found on nucleotides to create a bond. The carbohydrate found in the DNA biomolecule is deoxyribose, while the carbohydrate found in the RNA biomolecule is ribose.

O phosphate group

In other words, they are phosphates derived from the inorganic substance known as phosphoric acid. H3PO4. They build an ester linkage by combining forces with the sugars present in the nucleotides. Phosphate groups can occur in a variety of different combinations in nucleic acids.

base nitrogenada

There are five bases in total that contain nitrogen. In contrast, there are never more than four in the molecule that makes up a nucleic acid. Adenine, cytosine, guanine, the mineral thymine (only present in DNA), uracil (only present in RNA)


Purines and pyrimidines are the common nucleotides found in human genetic material. Both classes have molecules that are nonpolar and planar, such as pyridine. Each pyrimidine consists of a heterocyclic organic ring, just like pyridine. A pyrimidine ring and an imidazole ring combine to form purines. These two rings come together to form purines. Nitrogenous base in nucleic acids
Pyramid and PurinaIt is important to realize that there are two basic classes of nitrogenous bases. All nitrogenous bases have one thing in common: a 6-sided ring made up of four carbon atoms and two nitrogen atoms. A purine has one more carbon atom and two more nitrogen atoms, which together form an additional five-sided ring. A pyrimidine nitrogenous base has only one six-sided ring. Each nitrogenous base has a different set of bonds, which means they work differently in DNA or RNA.

base nitrogenada

While there are many nitrogen-containing bases, the 5 most important are those found in DNA and RNA. These nitrogenous bases serve not only in DNA and RNA, but also as potential carriers in biological processes. Adenine (A), Guanine (G), Cytosine (C), Thymine (T) and Uracil (U) are their respective names. To make DNA and RNA, each base has what's called a "complementary base" that it just binds to. The genetic code is based on how complementary bases work together.

Nucleic Acid: Definition, Function, Structure, and Types - GeeksforGeeks (1)


Purines are adenine and guanine. The chemical symbol for adenine is often represented by the letter A. In DNA, thymine is the accompanying base. Adenine is made up of C5H5N5 atoms. In RNA, uracil binds to adenine.
To make nucleotides, adenine and the other bases are joined to phosphate groups and either the ribose sugar or the 2'-deoxyribose sugar. Nucleotide names are similar to base names, but end in "-osine" for purines (e.g. "adenosine triphosphate" for adenine) and "-idine" for pyrimidines (e.g. la cytosine forms cytidine triphosphate) . The number of phosphate groups in a nucleotide is indicated by its name: monophosphate, diphosphate, or triphosphate. Both DNA and RNA are assembled from nucleotides, which can be considered building blocks. The double helix form of DNA is formed by hydrogen bonds between purine and its complementary pyrimidine. Hydrogen bonds can also speed up reactions.

Adenine has the following properties:

Adenine is one of two purine nitrogenous bases used to make nucleotides in nucleic acids. The other is guanine. Two hydrogen bonds attach adenine to thymine in DNA. This helps keep nucleic acid structures stable. RNA is used to make proteins. Adenine binds to uracil in RNA. When attached to ribose, adenine produces the nucleoside adenosine. When attached to deoxyribose, adenine produces the nucleoside deoxyadenosine. ATP, also known as nucleoside triphosphate, is made from adenosine by the addition of 3 separate phosphate groups. Adenosine triphosphate is used in cell metabolism as a basic way to move energy from one chemical reaction to another.


Guanine is a purine and is represented by a capital G. It can be chemically represented as C5H5N5O. Guanine forms a covalent bond with cytosine in DNA and RNA. Guanine produces guanosine, which is a type of nucleotide. Purines are found in large amounts in meat, particularly in organs such as the liver, brain and kidneys. Plants such as peas, beans and lentils have only a small amount of purines.

Guanine has the following properties:

Guanine, adenine, and cytosine are found in both DNA and RNA. Thymine, on the other hand, is normally found only in DNA and uracil is normally found only in RNA. Guanine has two tautomeric forms: the keto form, which is the most common (see figures), and the rare enol form. Three hydrogen bonds connect it to cytosine. The amino group of cytosine is what contributes to the formation of the H bond. On the other hand, the C-2 carbonyl function and the N-3 amine function are those that accept the H bond. The carbonyl group at C-6 in guanine is the hydrogen bond acceptor. The hydrogen bond donors are a group at N-1 and an amino group at C-2.


5-methyluracil is another name for thymine. Thymine is a pyrimidine that binds to adenine in DNA. Thymina is written with a capital T. The formula for this is C5H6N2O2.

thymine properties

It is a nitrogenous pyrimidine base. It consists of uracil with a methyl group in place of the hydrogen in the fifth position. In humans, E. coli and rodents, it serves as a metabolite and plays a role in the metabolic process. It's a nucleobase made up of pyrimidine and a pyrimidone.


The capital letter C stands for cytosine. It covalently binds to guanine found in DNA and RNA. In the Watson-Crick base pairing process, cytosine and guanine form three hydrogen bonds with each other. This is how DNA is made. Cytosine consists of C4H4N2O2 atoms. Cytidine is the nucleotide formed by cytosine.

cytokine properties

Cytosine is a type of pyrimidine base that pairs with guanine. It can be present in both RNA and DNA. Cytosine is an aminopyrimidine, which is pyrimidin-2-one with an amino group at position 4. It functions as a metabolite in human cells, as well as in E. coli cells, Saccharomyces cerevisiae cells, and mouse cells.


Uracil is like thymine that has been stripped of its methyl group. Uracil is represented by the capital letter U. The formula for this is C4H4N2O2. In nucleic acids, it is linked to adenine in RNA. The uridine nucleotide consists of uracil.
There are many other nitrogenous bases in nature, and the molecules can also be found in other compounds. For example, pyrimidine rings can be found in nucleotides, thiamine (vitamin B1) and barbiturates. Some meteorites also have pyrimidines, but nobody knows where they came from. Nature also has xanthine, theobromine, and caffeine, all of which are purines.

Uracil has the following properties

By forming bonds with ribose and phosphates, it helps produce many of the enzymes needed for a cell to function. Uracil is a coenzyme and an allosteric regulator used in animal and plant reactions. Uracil has these properties:

Composition of DNA and RNA

In DNA, bases are paired as follows:(A-T), (G-C).Since uracil is used instead of thymine in RNA, base pairing consists of the following: (AU),(GC)The nitrogenous bases are found at the center of the DNA double helix, and the backbone of the molecule is formed by the sugars and phosphates of each nucleotide. When a DNA helix splits, as when DNA is copied, complementary bases attach to each half, allowing two identical copies to be made. In translation, when RNA is used as a template to make DNA, complementary bases are used to build the DNA molecule from the sequence of bases.
Because purines and pyrimidines work well together, cells need about the same amount of each. In a cell, the production of purines and pyrimidines is self-inhibited. This keeps the cell in balance. When you're done, he stops doing more and starts doing the opposite.

The function of DNA

DNA is the genetic substance that stores all information about a person's ancestry. The tiny stretches of DNA known as genes typically have a sequence of between 250 and two million base pairs. A gene contains the instructions for making a polypeptide molecule; the sequence of three nitrogenous bases represents 1 amino acid.
To create different proteins, polypeptide chains must first fold further into secondary, tertiary, and finally quaternary structures. Because each creature's DNA contains a diverse collection of genes, a wide variety of proteins can be produced. In most living things, proteins serve as the primary morphological and anatomical molecules.
In addition to storing information about a person's genetic makeup, DNA is involved in the following processes:

  • The replication process involves the transfer of genetic information from one generation to the next.
  • transcription
  • cellular metabolism
  • Deoyribosenucleinsäure-Fingerprinting
  • genetic manipulation
  • genetic expression

The basic functions of RNA are as follows.

• Assist in the process by which DNA is translated into proteins
• Participates in protein production as an adapter molecule
• Works within the cell as a messenger substance between the ribosomes and the DNA in the cell's nucleus.
• They are responsible for transporting genetic information to all cells in the body.
• Motivates ribosomes to select the correct amino acid, which is essential for the formation of unique biomolecules in the human body.

question of concept

Question 1: What are the three different forms of DNA?


  • DNA-A
  • B-ADN
  • Z-ADN

Question 2: What makes Z-DNA unique compared to other types of DNA?


The Z-DNA molecule has a left-handed double helix structure. The helix has an irregular pattern that spirals to the left. In contrast, both DNA A and DNA B are examples of right-handed DNA.

Question 3: What type of DNA is discovered in humans?


B-DNA can be detected in humans. The construction has a double spiral orientation on the right.

Question 4: What molecules are DNA and RNA made of?


With the exception of base pairs, the nucleotide polymers that make up DNA and RNA are almost similar to each other. In RNA, the nucleotide thymine is converted to the base uracil, but in DNA the base thymine is retained.

Question 5: Where can DNA and RNA be obtained?


Both the nucleus and the mitochondria of a cell contain DNA. Deoxyribose nucleic acid would also be detected in the cytoplasm. RNA, on the other hand, can be located in the cytoplasm, in the cell nucleus and also in the ribosomes.

Question 6: How does the replication process in RNA and DNA work?


DNA has the ability to duplicate itself, but RNA does not; Instead, it must be copied from the DNA to be made when needed. DNA can replicate.

Question 7: Why is DNA considered superior to RNA as genetic material?


The sugar found in DNA known as deoxyribose has one less hydroxyl group that carries oxygen. DNA is a more stable nucleic acid than any other nucleic acid. On the other hand, DNA is less reactive than RNA due to the presence of ribose sugar in DNA. As a result, DNA is a superior genetic material to RNA.

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