Unit C

Module 5 ~ Lesson 5


All cellular respiration begins in the cell's cytoplasm with a process called glycolysis. It starts with a 6-carbon glucose molecule and consists of a series of oxidation-reduction reactions that essentially split glucose into two 3-carbon molecules called pyruvate. Pyruvate is then transported into the mitochondria for further processing and energy harvesting or remains available in the cytoplasm for the process of fermentation.

The mitochondrion is an organelle found in both plant and animal cells.

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The process of taking a phosphate group from ATP (resulting in it becoming ADP) and attaching it to the glucose molecule is called phosphorylation. This activates the glucose and enables it to be broken down into two 3-carbon molecules.

Electrons are donated to two molecules of NADto generate two molecules of NADH. In glycolysis 2 ATP molecules are used to activate glucose and 4 ATP are formed so there is a net energy yield of 2 ATP and 2 NADH molecules.


Read "The Process of Cellular Respiration", "Examining Aerobic Cellular Respiration", and "Outside the Mitochondria" on pages 182 to 186 of your textbook.


Glycolysis occurs in the cytoplasm of any cell.
Glycolysis does not require oxygen.