Class 12 · Principles of Inheritance and Variation

From Mendel to Molecular Biology — NEET Biology

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The work of Mendel and others who followed him gave us an idea of inheritance patterns. However the nature of those 'factors' which determine the phenotype was not very clear. As these 'factors' represent the genetic basis of inheritance, understanding the structure of genetic material and the structural basis of genotype and phenotype conversion became the focus of attention in biology for the next century. The entire body of molecular biology was a consequent development with major contributions from Watson, Crick, Nirenberg, Khorana, Kornbergs (father and son), Benzer, Monod, Brenner, etc. A parallel problem being tackled was the mechanism of evolution. Awareness in the areas of molecular genetics, structural biology and bio informatics have enriched our understanding of the molecular basis of evolution. In this unit the structure and function of DNA and the story and theory of evolution have been examined and explained.

NCERT Biology · Class 12 · Chapter 4 · Paragraph 1
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Match the scientists with their contributions: Column I A. James Watson B. Francis Crick C. Marshall Nirenberg D. Har Gobind Khorana E. Kornbergs (father and son) Column II (i) Synthesised RNA sequences in the lab (ii) DNA replication studies (iii) Deciphered the genetic code (iv) Double helix model with Crick (1953) (v) Ph.D. in “X-ray Diffraction: Polypeptides and Proteins” (1954)

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Correct answer: B A–(iv), B–(v), C–(iii), D–(i), E–(ii)

Watson with Crick → DNA double helix (1953). Crick → Ph.D. in X-ray diffraction, 1954. Nirenberg → deciphered the genetic code. Khorana → synthesised RNA sequences. Kornbergs → DNA replication studies.

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The work of Mendel and others who followed him gave us an idea of inheritance patterns. However the nature of those 'factors' which determine the phenotype was not very clear.
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Principles of Inheritance and Variation, Class 12 NCERT Biology.

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