RNA: Describe its Structure, Types, & Functions

RNA

RNA (ribonucleic acid)

It is produced by DNA in the nucleus and then transferred to the cytoplasm. It contains ribose. It is involved in protein synthesis. DNA and RNA are made up of small units called nucleotides. These nucleotides have three parts.

  • Pentose is composed of five carbon atoms.
  • DNA contains Deoxyribose.
  • RNA contains ribose.
  • Phosphoric acid group (Phosphoric acid).
  • Nitrogen base.

Nitrogen Bases are of different Types:

  • Adenine
  • Guanine
  • Cytosine
  • Thymine

Ribonucleic Acid (RNA):

Polymers of ribonucleotides are called RNA. Its molecules have only one edge. Sometimes, this series may bend back to provide a double helix characteristic. Nitrogen bases form complementary pairs.

Ribonucleic acid contains nitrogen-based uracil instead of thymine. Cytosine (C) is combined with guanine (G), and uracil (U) is combined with adenine (A). DNA synthesizes ribonucleic acid. The process of synthesizing ribonucleic acid from DNA is called transcription.

RNA Structure

RNA is typically a single-stranded biopolymer. However, the presence of self-complementary sequences in the RNA strand consists of base pairing and helicopters in a complex structure of base pairing and ribonucleotide strands within the strand. The three-dimensional structure of RNA is important for its stability and function. It can modify ribose and nitrogenous bases in many different ways through cellular enzymes that attach chemical groups (such as methyl) to the chain. Such modification leads to the formation of chemical bonds between regions outside the RNA strand, resulting in complex deformations in the RNA strand, which further stabilize the RNA structure. Molecules with weak structural modification and stability are easily destroyed. For example, in an initial transfer RNA (tRNA) molecule (tRNAiMet) that lacks a methyl group, modification of position 58 of the tRNA strand destabilizes the molecule and therefore fulfills its function. The cellular tRNA quality control mechanism destroys non-functional chains.

RNA can also form complexes with molecules called ribonucleoproteins (RNPs). The RNA portion of at least one cellular RNP has been shown to act as a biocatalyst, a function is previously only responsible for proteins.

Types And Functions Of RNA

There are three main types of RNA. These are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three types of RNA are synthesized from DNA in the nucleus. After being synthesized, they are transferred to the cytoplasm. All three RNAs (mRNA, tRNA, and rRNA) interact. They synthesize proteins from genetic information (genes).

1.Messenger RNA (mRNA)

The mRNA transmits genetic information from the nucleus to the ribosome. mRNA accounts for about 3% to 4% of the total RNA of the cell. Ribosomes are present in the cytoplasm and are used to synthesize specific proteins. DNA transfers its genetic information to mRNA.

Now, this mRNA contains genetic information for protein synthesis. mRNA consists of single strands of variable length. Its size depends on the gene size (on DNA) of the specific protein. For example, mRNAs contain 3,000 nucleotides of proteins of 1,000 amino acids.

2.Transfer RNA (tRNA)

The tRNA reads the information (code) on the mRNA and transfers specific amino acids to the ribosome. These amino acids are associated with forming polypeptide chains of proteins. Each amino acid has a specific tRNA. Therefore, the cell contains 20 types of tRNA. It accounts for 10% to 20% of the total RNA of the cell. The size of TRNA is small. Its range consists of 75 to 90 nucleotides.

3. Ribosomal RNA (rRNA)

rRNA combines with ribosomal proteins to form ribosomes. Ribosomes are made up of rRNA and proteins. rRNA contains 50% ribosome. This accounts for a large share, about 80% of the total imperial army. It acts as a protein synthesis machine.

RNA FUNCTIONS

piRNA also has a functional significance. It is approximately 26 to 31 nucleotides long and is present in most animals. They inhibit the expression of the transgene (jumping gene) by transferring the transgene to the germ cell (sperm and egg). Most piRNAs complement various transposons and may specifically target these transposons.

Circular RNA differs from other types of RNA because of its 5’and 3’end form a loop. circRNA is produced by many protein-coding genes, some are similar to mRNA, and can be used as a template for protein synthesis. They can also bind miRNAs and act as “sponges”, preventing miRNA molecules from binding to their targets. In addition, circRNA plays an important role in regulating transcription and alternative splicing of genes derived from circRNA.

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