Introduction to RNA

RNA, or ribonucleic acid, is a crucial molecule in biology that plays several roles in the expression of genes.

Composition: RNA is made up of nucleotides, which consist of a sugar (ribose), a phosphate group, and a nitrogenous base. The four nitrogenous bases in RNA are adenine (A), uracil (U), cytosine (C), and guanine (G). Unlike DNA, which has thymine (T) instead of uracil, RNA is single-stranded and typically shorter than DNA.
Types of RNA:
mRNA (Messenger RNA): Carries genetic information from DNA to the ribosomes, where proteins are synthesized.
tRNA (Transfer RNA): Transfers specific amino acids to the ribosome during protein synthesis.
rRNA (Ribosomal RNA): Forms the core of the ribosome’s structure and catalyzes protein synthesis.
snRNA (Small Nuclear RNA): Involved in RNA splicing, which is the process of removing introns from pre-mRNA.

Protein Synthesis: RNA is essential in translating the genetic code into proteins, which perform most of the functions in cells.

Transcription: The process where a segment of DNA is copied into mRNA by the enzyme RNA polymerase.
Translation: The mRNA is then translated into a protein at the ribosome, with tRNA bringing the appropriate amino acids in line with the mRNA code.

Gene Regulation: RNA molecules such as microRNAs (miRNAs) and small interfering RNAs (siRNAs) are involved in regulating gene expression by targeting mRNAs for degradation or inhibiting their translation.
Catalysis: Some RNA molecules, known as ribozymes, have catalytic properties and can act as enzymes. An example is the ribosome, which has rRNA with enzymatic activity to form peptide bonds.
Genetic Material in Some Viruses: In some viruses, RNA, rather than DNA, serves as the genetic material. These RNA viruses include the influenza virus, HIV, and the coronavirus responsible for COVID-19.

Single-Stranded vs. Double-Stranded: RNA is usually single-stranded, whereas DNA is double-stranded.
Sugar: RNA contains ribose, while DNA contains deoxyribose (which lacks one oxygen atom compared to ribose).
Base Pairing: RNA uses uracil instead of thymine, which pairs with adenine.