Question

1. In the boxes in the flow chart below, follow the flow of carbon atoms in the complete oxidation of glucose by indicating the beginning and ending molecules in each of the steps of cellular respiration starting with 1 molecule of glucose. Be sure to include the number of molecules of each type of molecule made from 1 molecule of glucose at each step. (Do not include other molecules made like NADH and ATP).

                               Glycolysis                 Pyruvate Processing               Citric Acid Cycle

Answer 1

GLYCOLYSIS : Coverts one glucose molecule to two pyruvate molecules. In the first phase of Glycolysis, 6 carbon glucose is broken down to two 3-carbon molecules as Glyceraldehyde-3- phosphate and DHAP. DHAP cannot proceed in glycolysis and all of them are converted into their isomer, Glyceraldehyde-3- phosphate. Thus, one molecule of glucose yields 2 molecules of Glyceraldehyde-3- phosphate, which will be converted into 2 molecules of pyruvate.

PYRUVATE PROCESSING: After glycolysis, pyruvate is converted into Acetyl CoA for complete oxidation by entering the citric acid cycle. During this conversion, each pyruvate loses one CO2.

CITRIC ACID CYCLE: After glycolysis, 2 molecules of pyruvate are produced which are converted into 2 molecules of Ac CoA to enter TCA cycle. Each molecule of Acetyl Co A produces 2 CO2 molecules during the TCA cycle. So, complete oxidation of one glucose molecule produces 6 CO2 molecules along with 10 NADH and two FADH2 .