Question

Which is the correct sequence according to increasing molecular weight?
A) tRNA-DNA-rRNA
B) tRNA-rRNA-DNA
C) rRNA-DNA-tRNA
D) DNA-tRNA-rRNA

Answer 1

Hint: DNA and RNA are the genetic material present in the organism. DNA is long and compact present in the chromosome of the nucleus whereas RNA is present in the cytoplasm of the cell. The DNA is converted into RNA by the process of transcription.

Complete answer:
The DNA is the carrier of the hereditary whereas the RNA is the biomolecule whose main role is protein synthesis. The DNA and RNA are made of bases Adenine, guanine, cytosine, thymine and uracil. The bases form pairing with each other. The size of the DNA or RNA is calculated on the basis of the base pairs present.

Let us discuss DNA and RNA:
DNA: It is the double-stranded molecule that is present in the nucleus of the eukaryotic cell. It carries information for growth, development, functioning and also reproduction. The DNA is arranged in the chromosome which is wound around the nucleosome which gives the appearance of a beaded string. The DNA contains the genes or the segments of the DNA which are responsible for the traits of a living being. The DNA contains more than 1000 bases so, the molecular mass of DNA is greater than that of RNA. The structure of DNA is as follows-

RNA: The RNA is the molecule that is responsible for protein synthesis. Its weight is less as compared to DNA. The RNA is of three types-
i) mRNA-It is also known as messenger RNA. It is produced as a result of transcription in the nucleus. It is around 100 bases.
ii) tRNA- It is also known as transfer RNA. It carries the message from the mRNA to the ribosomes. It is around 70-90 bases long. It is the smallest of all RNA.
iii) rRNA-It is present in the ribosome. The protein is synthesised in the rRNA. It is single-stranded. It is heavier than tRNA or mRNA.
The structure of the three types of RNA is as follows:

On the basis of molecular weight tRNA

Note: The adenine forms the bond with the thymine or uracil in the case of RNA. The bond is a double covalent bond. The cytosine form with guanine which is a triple covalent bond. These are called complementary bases. This helps in forming the two strands of DNA.