Enzymes as Biological Catalysts

Steps:

• Define enzymes as proteins that act as catalysts in biochemical reactions.
• Recall that catalysts lower activation energy to speed up reactions without altering equilibrium.
• Assess option A: Enzymes don't initiate impossible reactions; they accelerate feasible ones.
• Assess option B: Matches the core function of increasing reaction rates.
• Assess option C: Enzymes function outside living systems, like in lab tests.
• Assess option D: Enzymes exhibit specificity for particular substrates.

Why B is correct:

• Enzymes increase reaction rates by reducing activation energy, as per catalyst definition in biochemistry.

Why the others are wrong:

• A: Reactions occur without enzymes, albeit slowly; enzymes accelerate, not initiate.
• C: Enzymes catalyze reactions in vitro, not limited to living cells.
• D: Enzymes are substrate-specific; one typically catalyzes one reaction type.

Final answer: B