Egg and sperm cells

During respiration, the breakdown of glucose undergoes several steps in order to produce ATP, namely in glycolysis, the Kreb's cycle and oxidative phosphorylation.

overall: C6H12O6 (glucose) + 6 O2 → 6 CO2 + 6 H2O + ≈38 ATP

Further Explanation:

In all eukaryotic cells mitochondria are small cellular organelles bound by membranes, these make most of the chemical energy required for powering the biochemical reactions within the cell. This chemical energy is stored within the molecule ATP which is produced. Respiration in the mitochondria utilizes oxygen for the production of ATP in the Krebs’ or Citric acid cycle via the oxidization of pyruvate( through the process of glycolysis in the cytoplasm).

Oxidative phosphorylation describes a process in which the NADH and FADH2 made in previous steps of respiration process give up electrons in the electron transport chain these are converted it to their previous forms, NADH+ and FAD. Electrons continue to move down the chain the energy they release is used in pumping protons out of the matrix of the mitochondria.

This forms a gradient where there is a differential in the number of protons on either side of the membrane the protons flow or re-enter the matrix through the enzyme ATP synthase, which makes the energy storage molecules of ATP from the reduction of ADP. At the end of the electron transport, three molecules of oxygen accept electrons and protons to form molecules of water...

Glycolysis: occurs in the cytoplasm 2 molecules of ATP are used to cleave glucose into 2 pyruvates, 4 ATP and 2 electron carrying NADH molecules. (2 ATP are utilized for a net ATP of 2)

The Citric acid or Kreb's cycle: in the mitochondrial matrix- 6 molecules of CO2 are produced by combining oxygen and the carbon within pyruvate, 2 ATP oxygen molecules, 8 NADH and 2 FADH2.
The electron transport chain, ETC: in the inner mitochondrial membrane, 34 ATP, electrons combine with H+ split from 10 NADH, 4 FADH2, renewing the number of electron acceptors and 3 oxygen; this forms 6 H2O, 10 NAD+, 4 FAD.