Class X Biology - Chapter: Life Processes - Topic: Respiration Numerical Problems

Problem 1: ATP Production in Aerobic Respiration

If one molecule of glucose undergoes complete aerobic respiration, how many molecules of ATP are theoretically produced?

Solution:

Complete aerobic respiration of one glucose molecule involves glycolysis, Krebs cycle, and oxidative phosphorylation. The theoretical yield of ATP is as follows:

• Glycolysis: Net 2 ATP + 2 NADH (which yield 3 ATP each in ETS = 6 ATP)
• Pyruvate Oxidation (2 molecules): 2 NADH (which yield 3 ATP each in ETS = 6 ATP)
• Krebs Cycle (2 turns): 2 ATP (or GTP) + 6 NADH (which yield 3 ATP each in ETS = 18 ATP) + 2 FADH2 (which yield 2 ATP each in ETS = 4 ATP)

Total theoretical ATP yield = 2 (from glycolysis) + 6 (from glycolysis NADH) + 6 (from pyruvate oxidation NADH) + 2 (from Krebs cycle) + 18 (from Krebs cycle NADH) + 4 (from Krebs cycle FADH2) Total theoretical ATP yield = 38 ATP molecules

Therefore, 38 molecules of ATP are theoretically produced from the complete aerobic respiration of one glucose molecule.

Problem 2: Respiratory Quotient (RQ) Calculation

Calculate the Respiratory Quotient (RQ) for the complete oxidation of glucose.

Solution:

The Respiratory Quotient (RQ) is the ratio of the volume of carbon dioxide produced to the volume of oxygen consumed during respiration.

The balanced chemical equation for the complete aerobic respiration of glucose is:

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy

From the equation:

• Volume of CO2 produced = 6 molecules
• Volume of O2 consumed = 6 molecules

RQ = (Volume of CO2 produced) / (Volume of O2 consumed) RQ = 6 CO2 / 6 O2 = 1.0

Therefore, the Respiratory Quotient (RQ) for the complete oxidation of glucose is 1.0.