Q.It is established that RNA is the first genetic material. Justify giving reasons.

Step 1. Fraenkel-Conrat and Singer (1957) directly demonstrated that RNA alone, separated from protein, can act as the genetic material of RNA-containing viruses such as Tobacco Mosaic Virus (TMV), showing RNA is chemically capable of carrying hereditary information on its own.

Step 2. Unlike protein and DNA, RNA is uniquely capable of acting as BOTH the genetic material and a biological catalyst at the same time; catalytic RNA of this kind is called a ribozyme, and several essential biochemical reactions in living cells today are still catalysed by RNA rather than by protein enzymes.

Step 3. Because early life would have needed a molecule capable of both storing hereditary information and catalysing the chemical reactions needed for its own survival and replication, without yet having evolved separate, specialised DNA (for storage) and protein enzymes (for catalysis), RNA is the only known molecule capable of filling both roles simultaneously, which is why three independent molecular biologists (Orgel, Crick and Woese) proposed in the early 1980s that an 'RNA world' was the first stage in the evolution of life. …

Justify RNA's candidacy as the first genetic material through its unique dual capability (information storage plus catalysis as a ribozyme), citing the R …

• Simply asserting RNA came first without explaining WHY, i.e. omitting its unique dual role as both catalyst and information carrier, which is the actual basis of the argument. …