Ribonucleic acid (RNA) is one of the three major macromolecules (along with DNA and proteins) that are essential for all known forms of life.
Like DNA, RNA is made up of a long chain of components called nucleotides. Each nucleotide consists of a nuclear base (sometimes called a nitrogenous base), a ribose sugar, and a phosphate group. The sequence of nucleotides allows RNA to encode genetic information. For example, some viruses use RNA instead of DNA as their genetic material, and all organisms use messenger RNA (mRNA) to carry the genetic information that directs the synthesis of proteins.
Different types of RNA include Messenger RNA, which is a ‘mirror image’ of the DNA encoding the amino acid sequence for the protein specified by the gene. Transfer RNA is an RNA molecule that ‘activates’ the amino acid and recognizes the code specifying that amino acid in the mRNA sequence. Ribosomal RNA is RNA that has a structural role in a complex called the ribosome; the ‘machine’ that actually joins amino acids together to make proteins.
Like proteins, some RNA molecules play an active role in cells by catalyzing biological reactions, controlling gene expression, or sensing and communicating responses to cellular signals. One of these active processes is protein synthesis, a universal function whereby mRNA molecules direct the assembly of proteins on ribosomes. This process uses transfer RNA (tRNA) molecules to deliver amino acids to the ribosome, where ribosomal RNA (rRNA) links amino acids together to form proteins.
Most RNA molecules are single-stranded. Single-stranded RNA molecules adopt very complex three-dimensional structures, since they are not restricted to the repetitive double-helical form of double-stranded DNA. RNA is made within living cells by RNA polymerases; enzymes that act to copy a DNA or RNA template into a new RNA strand through processes known as transcription orRNA replication, respectively.
Like DNA, RNA is made up of a long chain of components called nucleotides. Each nucleotide consists of a nuclear base (sometimes called a nitrogenous base), a ribose sugar, and a phosphate group. The sequence of nucleotides allows RNA to encode genetic information. For example, some viruses use RNA instead of DNA as their genetic material, and all organisms use messenger RNA (mRNA) to carry the genetic information that directs the synthesis of proteins.
Different types of RNA include Messenger RNA, which is a ‘mirror image’ of the DNA encoding the amino acid sequence for the protein specified by the gene. Transfer RNA is an RNA molecule that ‘activates’ the amino acid and recognizes the code specifying that amino acid in the mRNA sequence. Ribosomal RNA is RNA that has a structural role in a complex called the ribosome; the ‘machine’ that actually joins amino acids together to make proteins.
Like proteins, some RNA molecules play an active role in cells by catalyzing biological reactions, controlling gene expression, or sensing and communicating responses to cellular signals. One of these active processes is protein synthesis, a universal function whereby mRNA molecules direct the assembly of proteins on ribosomes. This process uses transfer RNA (tRNA) molecules to deliver amino acids to the ribosome, where ribosomal RNA (rRNA) links amino acids together to form proteins.
Most RNA molecules are single-stranded. Single-stranded RNA molecules adopt very complex three-dimensional structures, since they are not restricted to the repetitive double-helical form of double-stranded DNA. RNA is made within living cells by RNA polymerases; enzymes that act to copy a DNA or RNA template into a new RNA strand through processes known as transcription orRNA replication, respectively.
