Name: Evolution of Man
Uploaded: 2019-07-19
Duration: 7 min 34 s
Description: The theory of evolution explains how modern species exist. But what about humans? How does this process affect our species? Find these answers in this video!

Question

Sketch and explain the structure of DNA and various types of RNA.

Accepted Answer

Structure of DNA

DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a nitrogen base, and a sugar group. It has a double helix structure like a ladder.

The phosphate and the sugar molecules form the side and the bases form the rings. As two strands of DNA are antiparallel, they run in the opposite direction.

Fig: A labelled diagram of DNA.

Structure of RNA

Unlike DNA, RNA is usually a single-stranded molecule that is linked by phosphodiester bonds. The sugar in RNA is ribose instead of deoxyribose.

RNA consists of four nitrogenous bases- adenine, cytosine, uracil, and guanine.

Various types of RNA: There are different types of RNA found in a cell, out of which mRNA, tRNA, and rRNA are considered to be the most important kinds of RNA.

mRNA: It is a single-stranded RNA made up of 1000 nucleotides which carries genetic code from DNA to the ribosomes, where protein synthesis takes place.

rRNA: It is a large and complex double-helical structures. It is a non-coding RNA, attached to ribosomes during initiation of protein synthesis.

tRNA: tRNA has a distinct folded structure that form the shape of a three-leafed clover. This RNA serves as physical link between the mRNA and the amino acid sequence of proteins.

Sketch and explain the structure of DNA and various types of RNA.

Important Questions on Heredity and Evolution

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