Short Answer

DNA and RNA are called nucleic acids because they are mainly found in the nucleus of the cell and show acidic nature. The acidic property comes from the phosphate group present in their structure.

Both DNA and RNA are made of nucleotides and were first discovered in the nucleus. Their location in the nucleus and their chemical nature together explain why they are known as nucleic acids.

Detailed Explanation :

Nucleic Acid Nature of DNA and RNA

DNA and RNA are grouped under a special class of biological molecules known as nucleic acids. This name is based on their location in the cell and their chemical structure. The term nucleic acid clearly explains both these features.

The word nucleic is derived from the word nucleus. DNA was first discovered inside the nucleus of the cell. At that time, scientists observed that this substance was closely associated with the nucleus. Later, RNA was also found to be related to nuclear activities, even though it is present in both the nucleus and cytoplasm. Because of this close connection with the nucleus, these molecules were called nucleic substances.

The word acid is used because DNA and RNA show acidic properties. This acidity is due to the presence of phosphate groups in their structure. Phosphate groups can release hydrogen ions, which makes the molecule acidic in nature. This acidic behavior is a key reason for calling DNA and RNA nucleic acids.

Structure Responsible for Acidic Nature

DNA and RNA are made up of small repeating units called nucleotides. Each nucleotide has three main parts: a sugar molecule, a nitrogen base, and a phosphate group. Among these three parts, the phosphate group is responsible for the acidic nature of nucleic acids.

In DNA, the sugar present is deoxyribose, while in RNA, the sugar is ribose. Even though the sugars are different, both DNA and RNA contain phosphate groups. These phosphate groups join nucleotides together to form long chains. Because phosphate groups are acidic, the entire molecule behaves as an acid.

When many nucleotides join together through phosphate bonds, they form a long chain of DNA or RNA. The repeated presence of phosphate groups along the chain gives DNA and RNA their strong acidic character. This is a common feature of all nucleic acids.

Relation with the Nucleus

Another important reason DNA and RNA are called nucleic acids is their close relation with the nucleus. DNA is mainly found in the nucleus of eukaryotic cells. RNA is produced in the nucleus using DNA as a template and then moves to the cytoplasm to perform its function.

Since both DNA and RNA are directly connected with nuclear activities like heredity and protein formation, the term nucleic is used for them. Their discovery in the nucleus played a major role in naming them nucleic acids.

Biological Importance of Nucleic Acids

DNA and RNA are not only nuclear and acidic in nature, but they also perform very important biological functions. DNA stores genetic information and passes it from one generation to the next. RNA helps in expressing this information by taking part in protein synthesis.

Because DNA and RNA control heredity, growth, and cell functions, they are essential for life. Their chemical structure allows them to interact with proteins and other molecules inside the cell. For example, DNA binds with histone proteins due to its acidic nature. This helps in proper packaging of DNA inside the nucleus.

In early scientific studies, DNA and RNA were isolated from the nucleus and showed acidic behavior during chemical tests. Based on these observations, scientists named them nucleic acids. Later research confirmed that this name correctly describes both their structure and function.

In simple terms, DNA and RNA are called nucleic acids because they are nuclear substances made of nucleotides with acidic phosphate groups. Their name reflects both where they are found and how they behave chemically.

Conclusion

DNA and RNA are called nucleic acids because they are associated with the nucleus and contain acidic phosphate groups in their structure. Their chemical nature, location, and role in heredity clearly justify this name. Understanding this helps in better understanding the basic nature of genetic material.