Question

The first formed organism (riboorganism) used only _______ for catalysing reactions.
(A) DNA
(B) Amino acids
(C) Fatty acids
(D) RNA

Answer 1

Hint: Ribooragnism as the name suggest is derived from ribonucleic acid that is RNA. So, they were entirely made up of RNA so they use only RNA to catalyse their reactions. As RNA also acts as an enzyme that is a ribozyme so it has catalysing ability as well.
Step-by-step solution:
Heterotrophic and anaerobic creatures were the first to exist on early Earth. There wasn't much oxygen on early earth. The structure of the contemporary creature is comparable to that of the earlier organisms. The earliest creatures to engage in photosynthesis are those with high oxygen content. Heterotrophs describe them. Analogous to cyanobacteria.
Options B and C are incorrect because amino acids and fatty acids cannot act as genetic material since they lack catalytic characteristics. Pyrimidine-sugar-phosphate and purine-sugar-phosphate were the building blocks for the creation of nucleic acids in the early, boiling soup of the sea. RNA may replicate itself and accelerate other chemical processes. As is well known, rRNA acts as a catalyst for the creation of peptide bonds during protein synthesis in modern organisms.
The existence of ribozymes—RNA molecules that act as enzymes—and sequence similarity between prokaryotic and eukaryotic rRNA indicate that these organisms' catalytic function was acquired earlier in evolution. In the early stages of life, RNA acted as an enzyme. Although RNA and proteins both had catalytic tasks, RNA's capabilities included self-replication, whereas proteins did not.
So, option (D) is correct.
Note: Catalytically active RNA molecules or RNA-protein complexes are known as ribozymes, in which just the RNA is responsible for catalysis. In the same sentence, the terms "enzymatic activity" and "ribonucleic acid nature" are used to describe a ribozyme. All creatures from all the kingdoms of life contain ribozymes in their genomes.