Question

Compare how many ATP molecules can be maximally formed by the breakdown of a glucose molecule in a cell lacking mitochondria, a cell that has mitochondria with ion channels specific to protons in its inner membrane, and a cell that has normal mitochondria.

Justifications for the calculations must be given and full accounts of the calculations must be provided so that the number of ATP molecules can be traced back to relevant reactions / processes.

Answer 1

Cellular respiration is the process that has a sequence of metabolic reactions that takes place in the organelles of the cell in- order to convert the chemical energy to Adenosine Triphosphate (ATP) which is the energy currency of the cell. The major steps involved in the production of energy (ATP) are Glycolysis followed by a link reaction, Citric acid cycle/ Krebs cycle, and the electron transport chain.

(i) Cell lacking mitochondria

Since the cell lacks the mitochondria the further steps of cellular respiration that takes place inside the mitochondria cannot proceed. Therefore, only 2 ATP molecules are produced from a glucose molecule and no further reaction takes place.

(iI) The cell that has mitochondria with ion channels specific to protons in its inner membrane

Since the mitochondrial inner membrane has ion channels specific to protons the H+ that get pumped through the ATP synthase gets attached to the ions and does not catalyze the ADP to ATP conversion. Therefore, only a total of 4 ATP are only produced.

(iii) With normal MitochondriaSince, the total cellular respiration takes place 36 ATPs are produced from one glucose molecule in cell with normal mitochondria