Question

Write out the complete process of respiration, including glycolysis, the Kreb's cycle, and electron transport chain, and oxidative phosphorylation. Highlight every substrate and product for each stage, and annotate the location of each stage in the cell.

Answer 1

In cellular respiration, a glucose molecule is gradually broken down into carbon dioxide and water. Along it's way, some ATP is produced directly in the reactions that transform glucose. Much more ATP is produced later in oxidative phosphorylation. Oxidative phosphorylation is powered by movement of electrons through the electron transport chain, a series of proteins embedded in the inner membrane of the mitochondrion.The location of each process in the cell is:

Glycolysis - Cytoplasm

Krebs cycle - Mitochondria

Electron Transport Chain and Oxidative phosphorylation- inner mitochondrial membrane

The 4 process are:

1. Glycolysis. In glycolysis, glucose—a 6 carbon sugar—undergoes a series of chemical transformations.It gets converted into two molecules of pyruvate, a three-carbon organic molecule. In these reactions, ATP is made,and NAD+ is converted into NADH.

2. Pyruvate oxidation. Pyruvate from glycolysis goes into the mitochondrial matrix—the innermost compartment of mitochondria. There, it’s converted into a two-carbon molecule bound to Coenzyme acetyl CoA. Carbon dioxide is released and NADH is generated.

3. Citric acid cycle. The acetyl CoA made in the last step combines with a four-carbon molecule and goes through a cycle of reactions, ultimately regenerating the four-carbon starting molecule. ATP ,NADH, FADH2 are produced, and carbon dioxide is released.

4. Oxidative phosphorylation. NADH and FADH2 made in other steps deposit their electrons in the electron transport chain, turning back into empty forms (NAD+ and FAD). As electrons move down ,energy is released and used to pump protons out of the matrix, forming a gradient. Protons flow back into the matrix through ATP synthase, making ATP. At the end of the electron transport chain, oxygen accepts electrons and takes up protons to form water.