{"id":6302,"date":"2026-01-06T07:42:53","date_gmt":"2026-01-06T02:12:53","guid":{"rendered":"https:\/\/vajiramandravi.com\/upsc-exam\/?p=6302"},"modified":"2026-01-07T11:05:10","modified_gmt":"2026-01-07T05:35:10","slug":"rna","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/upsc-exam\/rna\/","title":{"rendered":"RNA (Ribonucleic Acid)"},"content":{"rendered":"

Ribonucleic acid<\/strong>\u00a0(RNA) is a nucleic acid found in all living cells, often single-stranded, made of nucleotides containing ribose sugars, nitrogenous bases, and phosphate groups. It comes in three types:\u00a0messenger RNA<\/strong>\u00a0(mRNA),\u00a0ribosomal RNA<\/strong>\u00a0(rRNA), and\u00a0transfer RNA\u00a0<\/strong>(tRNA). Some RNAs regulate gene expression, while viruses may use RNA as their genetic material. RNA's main role is to create proteins through translation and serves as the primary genetic material for viruses.<\/p>\r\n

Structure of RNA<\/h2>\r\n

RNA is a nucleotide polymer composed of ribose sugar, phosphate, and bases such as adenine, guanine, cytosine, and uracil. Uracil, an RNA-specific pyrimidine, forms a complementary base pair with adenine and is used instead of thymine in\u00a0DNA.<\/strong><\/p>\r\n

\"Structure<\/figure>\r\n
    \r\n\t
  • Single Stranded:<\/strong>\u00a0The\u00a0majority\u00a0<\/strong>of RNA is single-stranded, but there are some double-stranded RNA viruses. The length and structure of the RNA molecule can vary.<\/li>\r\n\t
  • Double helix Characteristics:\u00a0<\/strong>Most RNA molecules are single-stranded but RNA molecules may contain regions that can form complementary base pairing where the RNA strand loops back on itself.\r\n\r\n
      \r\n\t
    • Non-complementary sequences may become looped out to form the bulge structure, an internal loop, or a\u00a0hairpin loop.<\/strong><\/li>\r\n\t
    • If so, some parts of RNA will have son double-stranded regions.<\/li>\r\n\t
    • Ribosomal RNAs (rRNAs<\/strong>) and transfer RNAs (tRNAs<\/strong>), as well as some messenger RNAs (mRNAs<\/strong>), have significant secondary structures.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t
    • The slight structural difference between the sugars adds stability to DNA, making it more suitable for genetic information storage, whereas RNA's\u00a0relative instability\u00a0<\/strong>makes it more suitable for its more\u00a0short-term functions.<\/strong><\/li>\r\n\t
    • Secondary structure:<\/strong>\u00a0Two hydrogen bonds form between adenine and uracil, while three bonds form between cytosine and guanine. The secondary structure of RNA is based on base pairing via hydrogen bonds.<\/li>\r\n\t
    • Tertiary Structure:\u00a0<\/strong>The RNA tertiary structure results from RNA folding, which produces a\u00a0three-dimensional shape<\/strong>\u00a0composed of helices and grooves.<\/li>\r\n<\/ul>\r\n

      Synthesis of RNA from DNA (Transcription)<\/h2>\r\n

      All of the RNA in a\u00a0cell\u00a0<\/strong>is made by transcription of DNA, a process that has certain similarities to the process of DNA replication.<\/p>\r\n

        \r\n\t
      • Process:<\/strong>\u00a0Transcription begins when a small portion of the DNA double helix is opened and unwound to expose the bases on each DNA strand.\r\n\r\n
          \r\n\t
        • One of the two strands of the DNA double helix is then used as a template to synthesize an RNA molecule.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t
        • Enzyme:<\/strong>\u00a0The enzymes that perform transcription are known as RNA polymerases.\r\n\r\n
            \r\n\t
          • RNA polymerases catalyze the formation of phosphodiester bonds, which connect nucleotides together to form a linear chain.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t
          • Substrates:\u00a0<\/strong>The substrates for the synthesis are nucleoside triphosphates (ATP, CTP, UTP, and GTP).<\/li>\r\n<\/ul>\r\n

            Types of RNA<\/h2>\r\n

            There are three types of RNA. They include\u00a0rRNA, mRNA, and tRNA.<\/strong>\u00a0RNA's\u00a0primary function<\/strong>\u00a0is to produce proteins via translation. RNA transports genetic information, which ribosomes convert into various proteins required for cellular functions.<\/p>\r\n

            \r\n\r\n\r\n\r\n\r\n\r\n\r\n
            Type<\/strong><\/td>\r\nFeatures<\/strong><\/td>\r\n<\/tr>\r\n
            \r\n

            Messenger RNA (mRNA)<\/strong><\/p>\r\n

            \"Messenger<\/figure>\r\n<\/td>\r\n
            		\r\n

            - Accounts for about\u00a05%<\/strong>\u00a0of the total RNA in the cell.<\/p>\r\n

            - It is made from a\u00a0DNA template<\/strong>\u00a0during the process of transcription.<\/p>\r\n

            - It contains the genetic code, which is copied from the DNA during transcription as triplets of\u00a0nucleotides\u00a0<\/strong>known as codons.<\/p>\r\n

            - A\u00a0transcriptome<\/strong>\u00a0is the full range of mRNA, molecules expressed by an organism.<\/p>\r\n

            -\u00a0Functions:<\/strong>\u00a0mRNA transcribes the genetic code from DNA into a form that can be read and used to make proteins.<\/p>\r\n

              \r\n\t
            • It transports genetic information from a cell's nucleus to the\u00a0cytoplasm<\/strong>.<\/li>\r\n<\/ul>\r\n<\/td>\r\n<\/tr>\r\n
            \r\n

            Ribosomal RNA (rRNA)<\/strong><\/p>\r\n

            \"Ribosomal<\/figure>\r\n<\/td>\r\n
            		\r\n

            - Found in the ribosomes and accounts for\u00a080%<\/strong>\u00a0of the total RNA present in the cell.<\/p>\r\n

            - Ribosomes comprise two major components:\u00a0small ribosomal subunits<\/strong>\u00a0that read RNA and\u00a0large subunits<\/strong>\u00a0that join amino acids to form a polypeptide chain.<\/p>\r\n

            -\u00a0Functions<\/strong>: rRNAs combine with proteins in the cytoplasm to form ribosomes, which serve as the site of protein synthesis and contain the necessary enzymes.<\/p>\r\n

              \r\n\t
            • It controls\u00a0mRNA translation<\/strong>\u00a0into proteins.<\/li>\r\n\t
            • They bind to tRNAs and other\u00a0protein-synthesis-related molecules.<\/strong><\/li>\r\n<\/ul>\r\n<\/td>\r\n<\/tr>\r\n
            \r\n

            Transfer RNA (tRNA)<\/strong><\/p>\r\n

            \"Transfer<\/figure>\r\n<\/td>\r\n
            		\r\n

            - tRNA is the\u00a0smallest\u00a0<\/strong>of the three types of RNA, with approximately 75-95 nucleotides.<\/p>\r\n

            -\u00a0Functions:<\/strong>\u00a0tRNA brings or transfers amino acids to the ribosome that correspond to each three-nucleotide codon of rRNA. The amino acids are then combined and processed to form\u00a0polypeptides<\/strong>\u00a0and\u00a0proteins<\/strong>.<\/p>\r\n

              \r\n\t
            • tRNAs also serve as adapters during the translation of mRNA's genetic sequence into proteins. As a result, they're also known as adapter molecules.<\/li>\r\n<\/ul>\r\n<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/figure>\r\n

              Functions of RNA<\/h2>\r\n

              RNA is considered a versatile biomolecule with various functions.<\/p>\r\n

                \r\n\t
              • In Protein Synthesis:\u00a0<\/strong>RNA makes proteins using amino acids. A protein's primary structure is made up of 20 different types of amino acids.\r\n\r\n
                  \r\n\t
                • When a\u00a0ribosome\u00a0<\/strong>binds to an mRNA transcript, it begins decoding the mRNA codons and recruits tRNAs with the encoded amino acid.<\/li>\r\n\t
                • Codons\u00a0<\/strong>are deciphered using the genetic code. Each codon in the genetic code represents a specific amino acid, such as\u00a0CUU for leucine<\/strong>\u00a0and\u00a0GGU for glycine.<\/strong><\/li>\r\n\t
                • The\u00a0genetic code<\/strong>\u00a0is redundant in the sense that different codons can code for the same amino acid.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t
                • For example,<\/strong>\u00a0UAU and UAC both code for tryptophan. When a ribosome has finished reading the mRNA, the amino acid sequence folds and forms a protein.<\/li>\r\n\t
                • Other functions\u00a0<\/strong>include RNA editing, gene regulation, and RNA interference. These processes are carried out by a category of\u00a0small regulatory RNAs<\/strong>\u00a0that includes small nuclear RNA, microRNA, and small interfering RNA.\r\n\r\n
                    \r\n\t
                  • RNA is the\u00a0nucleic acid<\/strong>\u00a0messenger between DNA and ribosomes.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t
                  • RNA as a genetic material and catalyst:<\/strong>\u00a0RNA was the first genetic material. There is evidence that RNA played a role in the evolution of essential life processes such as\u00a0metabolism, translation, and splicing<\/strong>.\r\n\r\n
                      \r\n\t
                    • RNA is used to act as a genetic material in some organisms (viruses) as well as a catalyst (some important biochemical reactions in living systems are catalysed by\u00a0RNA catalysts<\/strong>\u00a0and not by protein enzymes). But, RNA being a catalyst was reactive and hence unstable.<\/li>\r\n\t
                    • Therefore, DNA has evolved from RNA with chemical modifications that make it more stable. DNA being\u00a0double-stranded<\/strong>\u00a0and having complementary strands further resists changes by evolving a repair process.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n

                      Difference between DNA and RNA<\/h2>\r\n

                      The Key differences between DNA and RNA are listed below:<\/p>\r\n

                      \"DNA<\/figure>\r\n
                      \r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
                      Features<\/strong><\/td>\r\nDNA<\/strong><\/td>\r\nRNA<\/strong><\/td>\r\n<\/tr>\r\n
                      Structure<\/strong><\/td>\r\nUsually\u00a0double-stranded,<\/strong>\u00a0(In certain viruses, DNA is single-stranded).<\/td>\r\nMost cellular RNA is\u00a0single-stranded<\/strong>. (Some viruses e.g. retrovirus, have double-stranded RNA).<\/td>\r\n<\/tr>\r\n
                      Pentose Sugar<\/strong><\/td>\r\nDeoxyribose<\/td>\r\nRibose<\/td>\r\n<\/tr>\r\n
                      Bases<\/strong><\/td>\r\nAdenine, Guanine, Cytosine, and\u00a0Thymine.<\/strong><\/td>\r\nAdenine, Guanine, Cytosine, and\u00a0Uracil<\/strong>.<\/td>\r\n<\/tr>\r\n
                      Base Pairing<\/strong><\/td>\r\nAdenine pairs with thymine and guanine with cytosine.<\/td>\r\nAdenine pairs with uracil and guanine with cytosine.<\/td>\r\n<\/tr>\r\n
                      Composition<\/strong><\/td>\r\nDNA consists of a large number of nucleotides, up to 4.3 million.<\/td>\r\nRNA consists of fewer nucleotides, up to 12,000.<\/td>\r\n<\/tr>\r\n
                      Transcription and Replication\u00a0<\/strong><\/td>\r\nDNA on replication forms DNA, and on transcription forms RNA.<\/td>\r\nUsually, RNA does not replicate or transcribe.<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/figure>","protected":false},"excerpt":{"rendered":"

                      Ribonucleic acid (RNA) is a nucleic acid present in all living cells and it is most often single-stranded. Learn about RNA structure, types, functions, etc here.<\/p>\n","protected":false},"author":6,"featured_media":20258,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[239],"tags":[40,699],"class_list":{"0":"post-6302","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-quest-level-4","8":"tag-quest","9":"tag-rna-ribonucleic-acid"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/6302","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/comments?post=6302"}],"version-history":[{"count":1,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/6302\/revisions"}],"predecessor-version":[{"id":19989,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/6302\/revisions\/19989"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/media\/20258"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/media?parent=6302"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/categories?post=6302"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/tags?post=6302"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}