NEET'22 Crash Course

What is Nucleic Acid?

Nucleic acids are natural polymers that are produced by cells of living organisms. It is crucial to all known forms of being as they are the chief information-carrying molecules of cells. Nucleic Acids are made up of nucleotides, a monomer composed of a 5-carbon sugar, a nitrogenous base, and a phosphate group. 

By supervising the process of protein synthesis, these biopolymers specify the inherited peculiarities of living beings. 


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Now that you know what nucleic acid is and what nucleic acids are made up of, it should be noted that there are two main groups of nucleic acids. One is ribonucleic acid, better known as RNA, and the other is deoxyribonucleic acid (DNA). 

RNA constitutes the genetic substance of certain viruses and is also found in living cells, playing a substantial part in specific processes such as preparing proteins. There are three established types of RNA, also known to be examples of nucleic acids. In contrast, DNA is the blueprint for being. Thus, it constitutes the genetic substance in all free-living organisms and most viruses. 


Nucleotides: The Elementary Unit of Nucleic Acid

Properties of Nucleic Acid

Now that you know what is nucleic acid, let's take a look at the nucleic acid structure. The basic nucleic acid structure is similar to a chain of molecules composed of identical series of nucleotides. Single nucleotide, the base property of nucleic acid, comprises a nitrogen-containing fragrant base affixed to a five-carbon sugar connected to a phosphate group. 

Every nucleic acid encompasses four of five possible nitrogen-containing bases, which are, uracil (U), adenine (A), thymine (T), guanine (G), and cytosine (C). Among these nitrogen-containing bases,  C, U, and T are classified as pyrimidines and A and G are classified as purines. An artificially synthesised polymer is also named Peptide Nucleic Acid (PNA), similar to DNA or RNA. Peptide Nucleic Acid might be similar to DNA and RNA. Its function varies from that of both. 

Generally, all nucleic acids contain the bases G, A, and C. But T is specifically found in DNA while U is in RNA. 


Two Types of Nucleic Acids

There are two types of nucleic acids, which are given in the following.

  • Deoxyribonucleic Acid (DNA)

DNA (deoxyribonucleic acid) is a form of nucleic acid that contains the genetic substance employed for the growth and functioning of all inferred living organisms. Deoxyribonucleic acid is a polymer of four nucleotides, C, T, A, and G integrated through a backbone of alternating phosphate and deoxyribose sugar remnants. 

As restricted by their capacity to form hydrogen bonds between them, these nitrogen-containing bases occur in complementary pairs. A invariably pairs with T through two hydrogen bonds, while G pairs with C through three hydrogen bonds. 

Since the span of both the hydrogen-bonded pairs is almost identical, the sugar-phosphate chains are uniformly bridged. This layout, along with the molecule's chemical stability, stimulates DNA (deoxyribonucleic acid) as the exemplary genetic material. Moreover, the bonding between the complementary bases procures a mechanism for the reproduction of DNA and the transmission of genetic information.  

  • Ribonucleic Acid (RNA)

RNA is a single-stranded nucleic acid that converts genetic input from genes into amino acid sequences of proteins. Ribonucleic acid is a polymer of four nucleotides, G, A, U, and C, integrated through a backbone of alternating phosphate and ribose sugar remnants. 

Ribonucleic acid is the first mediator in converting the information from Deoxyribonucleic acid into proteins essential for a cell's working. Few RNAs also perform immediate roles in cellular metabolism. 

RNA is produced by cloning the base sequence of a part of double-stranded DNA, called a gene, into a piece of single-stranded nucleic acid. This means transcription is catalysed by an enzyme called RNA polymerase.

There are Three Established Types of RNA:

  • Transfer RNA (tRNA): Works as the transmitter molecule for amino acids to be employed in protein synthesis and is accountable for decoding the mRNA.

  • Messenger RNA (mRNA): Transfers genetic sequence data between DNA and ribosomes, regulating protein synthesis and carrying directions from DNA (deoxyribonucleic acid) in the nucleus to the ribosome.

  • Ribosomal RNA (rRNA): Studies the Deoxyribonucleic acid sequence and catalyses peptide bond formation.


Difference Between DNA and RNA

Despite both being used to store genetic information, both examples of nucleic acids are different from one another. This table summa the primary points:

Comparison

DNA

RNA

Function

Storage of genetic information for a prolonged period and transmission of genetic information to prepare other cells and new organisms. 

It is used to store genetic information in primitive organisms and transfer genetic code from the nucleus to ribosomes to create protein. 

Structural feature

A B-form double helix, consisting of a long chain of nucleotides. 

An A-form single helix consisting of shorter chains of nucleotides. 

Propagation 

Self-replicating.

Synthesised from DNA for an as-needed purpose.

Base Pairing 

AT (adenine-thymine)

GC (guanine-cytosine)

AU (adenine-uracil)

GC (guanine-cytosine)


Functional Nucleic Acids (FNAs)

Functional nucleic acids are a group of biomolecules that can exhibit either ligand binding or enzymatic activity. Functional nucleic acid-based biosensors are emerging methods that can regulate ions and metabolites in cell populations or whole animals.

 

Did You Know?

  • Nucleic acids are made up of nucleotides and can steer the course of protein synthesis, therefore regulating all cell activities.

  • tRNA, mRNA, rRNA are prominent examples of nucleic acids.

  • Over the evolution process, humans have lost over 500 DNA codes.

  • DNA tests could help you comprehend your risk for heritable diseases.

  • The two types of nucleic acids, DNA and RNA, are composed of nearly similar material but differ in function and structure.

  • Around 9% of our DNA is the same as other humans.

  • Around 5% weight of a human cell is RNA, while only 1% consists of DNA.

  • RNA is utilised in some cancer gene therapies to lessen the articulation of cancer-causing genes.  

  • An artificially synthesised polymer named Peptide Nucleic Acid (PNA) is similar to DNA or RNA.

FAQs (Frequently Asked Questions)

1. What is transcription? Where does it take place?

Ans: Transcription means the deoxyribonucleic acid code of a gene is imitated to create mRNA (messenger RNA). DNA is too large to go through the nuclear pores and carries multiple codes that aren't always required at a given time. So, the m-RNA takes that necessary code to create specific proteins from the nucleus to the ribosome. Transcription takes place in the nucleus.

2. Define the function of all types of Ribonucleic acid. 

Ans: There are three types of ribonucleic acid, namely:

  • mRNA: Carries the DNA code from the nucleus to the ribosome so that transcription can synthesise proteins. 

  • t-RNA: Picks up amino acids in the cytoplasm and provides them to the ribosomes. The ribosome attaches the t-RNA anticodons to the mRNA codons, so it correctly lines up amino acids.

  • rRNA: Makes up the ribosomes. One longer rRNA makes up the large ribosomal subunit, and one shorter rRNA makes up the small ribosomal subunit.

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