Numerical Problems: Respiration in Plants

Q1: Calculate the Respiratory Quotient (RQ) for the complete oxidation of Tripalmitin, a fatty acid with the formula C₅₁H₉₈O₆.

Solution: The balanced equation for the oxidation of Tripalmitin is: 2C₅₁H₉₈O₆ + 145O₂ → 102CO₂ + 98H₂O RQ = Volume of CO₂ evolved / Volume of O₂ consumed RQ = 102 / 145 ≈ 0.7

Q2: If 4 molecules of glucose enter glycolysis, what is the net production of ATP and NADH?

Solution: For each molecule of glucose, glycolysis produces a net of 2 ATP and 2 NADH. For 4 molecules of glucose: Net ATP = 4 * 2 = 8 ATP Net NADH = 4 * 2 = 8 NADH

Q3: A plant is respiring using a substrate with the chemical formula C₄H₆O₅. Calculate the RQ.

Solution: The balanced equation for the oxidation of this organic acid (Malic Acid) is: C₄H₆O₅ + 3O₂ → 4CO₂ + 3H₂O RQ = Volume of CO₂ evolved / Volume of O₂ consumed RQ = 4 / 3 ≈ 1.33

Q4: In an experiment, 10 molecules of CO₂ are evolved and 10 molecules of O₂ are consumed. What is the RQ and what type of substrate is being used?

Solution: RQ = Volume of CO₂ evolved / Volume of O₂ consumed RQ = 10 / 10 = 1 An RQ of 1 indicates that the respiratory substrate is a carbohydrate.