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6.01 Molecule of Life

Posted10/11/2024
Updated21/12/2024
ByBMF
Views40

Genetic code

Key Requirements for a Genetic Molecule

1.Ability to Store Information:

  • The genetic molecule must store instructions for controlling cell activities and organism development.
  • These instructions guide functions such as cell growth, division, and differentiation.

2.Ability to Replicate Accurately:

  • The molecule must be able to copy itself precisely.
  • Accurate replication ensures each daughter cell inherits an identical set of instructions, preserving genetic information across generations.

Historical Perspective on the Genetic Molecule

  • Initial Assumptions:
    • Until the 1940s, biologists believed proteins were the genetic material.
    • Proteins were considered sufficiently complex to encode the vast instructions needed for life, due to their diverse structures and functions.
  • Discovery of DNA as the Genetic Molecule:
    • 1940s–1950s: Scientific evidence confirmed that the genetic material is DNA (deoxyribonucleic acid), not protein.
    • This discovery highlighted DNA’s role in storing and transmitting genetic information.

Summary

  • Proteins were initially thought to be the genetic material due to their complexity, but DNA was eventually proven to be responsible for heredity.
  • DNA meets the criteria for the genetic molecule through its capacity for information storage and accurate replication.

The work of pioneering scientists (a) James Watson, Francis Crick, and Maclyn McCarty led to our present day understanding of DNA. Scientist Rosalind Franklin discovered (b) the X-ray diffraction pattern of DNA, which helped to elucidate its double helix structure. 

Rosalind Franklin was an English chemist and X-ray crystallographer whose work was central to the understanding of the molecular structures of DNA

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