Proteins and RNA act as biological catalysts, while phospholipids do not. The correct answer is (A) P and Q only.

Option Analysis

• P (Protein): Proteins function as enzymes, the primary biological catalysts that accelerate biochemical reactions in living organisms without being consumed.​

• Q (RNA): Certain RNA molecules, known as ribozymes, exhibit catalytic activity, such as in self-splicing introns and the ribosome’s peptidyl transferase center.​

• R (Phospholipid): Phospholipids serve as structural components of cell membranes, forming lipid bilayers, but lack catalytic properties.​

Biological catalysts protein RNA drive essential reactions in cells, with proteins as traditional enzymes and RNA as ribozymes. This guide breaks down the MCQ on molecules acting as biological catalysts, ideal for competitive exams like IIT JAM.

Role of Proteins

Proteins dominate as biological catalysts through enzymes like amylase and DNA polymerase, lowering activation energy for reactions.​
Their active sites ensure specificity, vital for metabolism and DNA replication.
Denaturation by heat or pH disrupts this function.

RNA as Catalysts

RNA molecules catalyze via ribozymes, discovered in the 1980s, challenging protein-only enzyme views.​
Examples include RNase P for tRNA processing and ribosomal RNA in peptide bond formation.​
This supports the RNA World hypothesis for early life.

Why Not Phospholipids?

Phospholipids maintain membrane fluidity and barriers but do not catalyze reactions.​
They feature hydrophilic heads and hydrophobic tails, suited for structure over catalysis.
No known enzymatic role exists for them.

Exam Insights

For IIT JAM, recognize P and Q as catalysts, selecting option (A).​
Ribozyme knowledge tests molecular biology depth.
Practice similar MCQs to master enzyme concepts.