Nucleic Acids Study Guide
Introduction:
Nucleic acids are the information-carrying molecules of the cell. They determine the inherited characteristics of every living thing. They are present in viruses too. Friedrich Miescher discovered nucleic acids in 1868. They are indeed an important aspect of biochemistry.
What are nucleic acids?
- Nucleic acids are biomolecules that are important for the sustenance of all life forms.
- They consist of nucleotides, monomers built with a nitrogenous base, a phosphate group, and five carbon sugar bonds.
- The most important classifications of nucleic acids are commonly known as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
- They are predominantly found in cells and viruses.
Role of nucleic acids:
The most vital role of nucleic acids in living beings is to store genetic information; they are created with four bases. An isolated strand of nucleic acid has sufficient information about the organism, and the nucleic acid molecules contain and copy genetic information.
What is the function of nucleic acids in the body?
Nucleic acids perform several roles; chief among them are the functions of DNA and RNA in the human body. Some of them are as follows:
Information carriers- Cells require genetic information for protein production machinery. Cells have a central nucleus that consists of genetic material in DNA. Nucleic acids encode genetic information and transfer it between two cells and pass it on to the next generation through their progenies.
Amino acids- Protein production requires a type of nucleic acid, known as ‘transfer RNA ‘ or ‘tRNA.’ It builds proteins by putting together amino acids in the correct order.
Similarities and differences between DNA and RNA
DNA acts as genetic material. However, it became clear that RNA is the genetic material (for example, Tobacco Mosaic viruses, QB bacteriophage, etc.). The reason behind the discovery of DNA as the predominant genetic material, while RNA as the dynamic messenger and adapter has to be found from the differences between chemical structures of the two nucleic acid molecules.
A molecule that can act as a genetic material must fulfill the following criteria:
(i) It should have the ability to generate its replica (Replication).
(ii) It must remain stable chemically and structurally in spite of physiological changes.
(iii) It should provide the scope for slow changes (mutation) required for evolution.
(iv) It should express itself in the form of ‘Mendelian Characters.’
The rule of base pairing and complementarity suggests that DNA and RNA are capable of duplications. All other living organisms do not qualify for the first test itself. The stability of these genetic acids matters because they should be capable of withstanding several biological changes. Griffith’s ‘transforming principle’ propounded that heat-killed the bacteria; however, it did not destroy some of the characteristics of the genetic material, keeping it intact.
- The two strands of DNA are complementary if separated by heating and come together when appropriate conditions are provided.
- Further, the 2′-OH group present at every nucleotide in RNA is a reactive group and makes RNA labile and easily degradable.
- RNA is also now known to be catalytic, hence reactive. Therefore, DNA chemically is less reactive and structurally more stable when compared to RNA.
- Among the two nucleic acids, DNA is a better genetic material because of the thymine present in the uracil.
- Both DNA and RNA can mutate, but RBA is an unstable nucleic acid that mutates at a faster rate. Consequently, viruses having an RNA genome and having a shorter life span mutate and evolve faster.
- RNA can directly code for the synthesis of proteins, hence can easily express the characters. DNA, however, is dependent on RNA for the synthesis of proteins.
The above discussion indicates that both RNA and DNA can function as genetic material, but DNA being more stable is preferred for the storage of genetic information. RNA is responsible for the transmission of genetic information.
How do nucleic acids work?
The cell encodes information and transmits it via these acids. The sequence of the molecules in the DNA, RNA, etc., polymers coveys’ messages of protein production, replication of genetic material, transmission to the nucleus, etc. These acids are stable forms of proteins; thus, they are perfect carriers because the stability ensures that they do not break the chain by falling apart while communicating. Initially, they were termed nucleic acids because of their acidic properties and existence in the cell’s nucleus.
Double helix
A DNA molecule is a double helix made up of two strands of polymers that complement each other but are not identical. The DNA base pairs are adenine, cytosine, guanine, and thymine. The hydrogen bond holds the entire structure together.
Conclusion:
- Nucleic acids are biological blockchains that can be found in cells and viruses.
- The functions of a nucleic acid involve coding and decoding genetic information and carrying out various tasks based on them.
FAQs:
1. What are the two main nucleic acids?
Here are the two main nucleic acids:
- RNA (Ribonucleic acid)
- DNA (deoxyribonucleic acid)
2. What are the functions of nucleotides?
Functioning of Nucleotides:
- Nucleotides are the basic units of nucleic acids (DNA and RNA).
- Cyclic Nucleotides Act as Regulatory Chemicals.
- Nucleotides of B-Complex Vitamins Function as Coenzymes
- Higher nucleotides function as energy carriers, e.g., ATP, GTP, UTP, and TTP.
3. What are the types of RNA?
Types of RNA include:
- Messenger RNA
- Ribosomal RNA
- Transfer RNA
- Micro RNA
4. What are the functional groups of nucleic acids?
The functional groups of nucleic acids are one phosphate group, one nitrogen-containing base (pyrimidine or purine), and a sugar molecule, which in turn has alcohol and aldehyde/ketone group.
5. What are the biological elements of nucleic acids?Nucleic acids are composed of a nitrogenous heterocyclic base which is either a purine or pyrimidine, a pentose (five-carbon) sugar (either ribose or 2′-deoxyribose), and one to three phosphate groups.
6. What is the significance of nucleic acids to all living things?
Nucleic acids are abundant in all living organisms and function in encoding, transmitting, and expressing genetic information. They are the main information-carrying molecules of the cell, and by directing the process of protein synthesis, they determine the inherited characteristics of all living things.
7. Are nucleic acids water soluble?
Yes, nucleic acids are soluble in water and water solvents because of their polar nature. Individually, nucleotides are highly water-soluble as against nucleosides that have lesser water solvency.
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Sources:
- Nucleic Acids https://www.britannica.com/science/nucleic-acid. Accessed 17 Dec, 2021.
- DNA https://www.britannica.com/science/nucleic-acid/Deoxyribonucleic-acid-DNA. Accessed 17 Dec, 2021.
- Functions https://www.sciencedirect.com/topics/medicine-and-dentistry/nucleic-acid. Accessed 17 Dec, 2021.
- RNA https://www.genome.gov/genetics-glossary/RNA-Ribonucleic-Acid#:~:text=Ribonucleic%20acid%20(RNA)%20is%20a,(ribose)%20and%20phosphate%20groups.&text=Differ. Accessed 17 Dec, 2021.
- Plant. https://www.livestrong.com/article/307691-sources-of-nucleic-acids/. Accessed 17 Dec, 2021.
- Nucleic Acids https://apcentral.collegeboard.org/pdf/ap-biology-course-and-exam-description-0.pdf?course=ap-biology. Accessed 17 Dec, 2021.