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Dr. DHANASREE
tRNA or transfer RNA is a type of RNA, which helps in the synthesis of protein from mRNA. tRNA functions as an adapter molecule during the translation process.It was earlier known as soluble RNA or sRNA. As an adapter, it links the amino acids to nucleic acids. It carries the amino acid to be added in the peptide chain and also deciphers the codon for the same in the mRNA molecule.The tRNAs are generally 76-90 nucleotides long. Each amino acid has specific tRNAs. Stop codons are not recognised by any tRNAs. The secondary structure of tRNA looks like a clover leaf and tertiary structure is like an inverted ‘L’ shape. The folded structure is formed due to hydrogen bonding between complementary bases.
Transfer ribonucleic acid (tRNA) is a type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein. tRNAs function at specific sites in the ribosome during translation, which is a process that synthesizes a protein from an mRNA molecule. Proteins are built from smaller units called amino acids, which are specified by three-nucleotide mRNA sequences called codons. Each codon represents a particular amino acid, and each codon is recognized by a specific tRNA. The tRNA molecule has a distinctive folded structure with three hairpin loops that form the shape of a three-leafed clover. One of these hairpin loops contains a sequence called the anticodon, which can recognize and decode an mRNA codon. Each tRNA has its corresponding amino acid attached to its end. When a tRNA recognizes and binds to its corresponding codon in the ribosome, the tRNA transfers the appropriate amino acid to the end of the growing amino acid chain. Then the tRNAs and ribosome continue to decode the mRNA molecule until the entire sequence is translated into a protein.
Ribonucleic acid (RNA) is a molecule that is present in the majority of living organisms and viruses. It is made up of nucleotides, which are ribose sugars attached to nitrogenous bases and phosphate groups. The nitrogenous bases include adenine, guanine, uracil, and cytosine. RNA mostly exists in the single-stranded form, but there are special RNA viruses that are double-stranded. The RNA molecule can have a variety of lengths and structures. An RNA virus uses RNA instead of DNA as its genetic material and can cause many human diseases. Transcription is the process of RNA formation from DNA, and translation is the process of protein synthesis from RNA. The means of RNA synthesis and the way that it functions differs between eukaryotes and prokaryotes. Specific RNA molecules also regulate gene expression and have the potential to serve as therapeutic agents in human diseases.
In this section, we learn the structure of the DNA molecule and explain in general terms how it is able to store hereditary information. DNA is the information molecule. It stores instructions for making other large molecules, called proteins. These instructions are stored inside each of your cells, distributed among 46 long structures called chromosomes. These chromosomes are made up of thousands of shorter segments of DNA, called genes. We will learn about the nucleotides and nucleosides. The DNA molecule consists of two strands that wind around one another to form a shape known as a double helix. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups. Attached to each sugar is one of four bases--adenine (A), cytosine (C), guanine (G), and thymine (T).Nucleic acid structure is often divided into four different levels: primary, secondary, tertiary, and quaternary. The 3-dimensional double helix structure of DNA, correctly elucidated by James Watson and Francis Crick. Complementary bases are held together as a pair by hydrogen bonds.
This topic explains about micronutrients Vitamins and different type of vitamins in brief....