Just question 8, thank you! (BIOCHEMISTRY) e. -118.85 kJ/mol 8. One of the most
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Just question 8, thank you! (BIOCHEMISTRY)
e. -118.85 kJ/mol 8. One of the most plausible theories explaining the development of life on earth states that a. DNA-like molecules arose first, since they are stable carriers of information. b. Protein-like molecules arose first, since they are capable of catalysis. c. RNA-like molecules arose first, since they allow both catalysis and information storage. d. DNA-like and protein-like molecules arose at the same time, allowing catalysis and information storage. e. RNA-like molecules arose first, since they can serve as information carriers and form a cell wall 9. How does a buffer resist change in nHExplanation / Answer
Ans. Correct option- C. RNA-like molecules arose first, since they can allow both catalysis and information storage. Two of the most important features of a cell are “catalysis” and “genetic material” – without which life can’t continue forever. Since RNA is the only group of biomolecules which possess both the characteristics, the first life forms on the Earth is proposed to have been originated with RNA.
Walter Gilbert, 1986 coined the phrase ‘RNA World’. RNA World hypothesis emphasizes that during evolution of life on Earth, around 3.8- 3.5 billion years ago, all the life forms were based on RNA. For a molecule to act as ‘living’ on primitive earth, it must had been able of acting as the genetic material as well as a catalyst (enzyme) for reproducing (make new copies) itself. RNA still acts as genetic material in many of present day viruses. Ribozymes (catalytic RNA), for example R3C ribozyme, can make new copies of RNA from an RNA template.
# DNA acts as genetic material but can’t do catalysis. Without catalysis a cell can’t do its metabolic activities, so can’t sustain.
# Proteins can catalyze metabolic reactions but can’t act as genetic material. In absence of genetic material, a cell can’t exist.
# RNA don’t form cell wall.
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