Cellular Respiration

Cellular Respiration is a process in where oxygen is needed so that organisms can break down food molecules in order to get energy. Cellular Respiration can occur in plants in the mitochondria of plant cells. Cellular Respiration occurs in both plants and animals that require oxygen.

Why is Cellular Respiration important to plants?

Cellular Respiration is important to plants because plants need energy in order to grow. With Cellular Respiration, plants would be able to break down glucose into ATP and ATP would give energy to the plant so that the plants can carry out its functions.

Four Steps to Cellular Respiration in Plants:

• Glycolysis is the first stage in cellular respiration. It’s an anaerobic process meaning it doesn’t require oxygen. At the end of the process of Glycolysis, the results then occur in the matrix and that stage is called pyruvate oxidation.

• Pyruvate Oxidation is an aerobic process and requires oxygen and is the second stage. 

• Krebs Cycle aka Citric Acid Cycle and is the third stage in cellular respiration. It’s an aerobic process so it requires oxygen.

• Electron Transport Chain is the fourth stage in cellular respiration. It requires oxygen so it’s an aerobic process.

Each stage has a place in the plant cell where they occur. Glycolysis occurs in the cytosol of the plant cell. The Krebs Cycle occurs in the matrix and the electron transport chain occurs in the inner membrane.

For the four stages to occur, you have to have a well understanding of the cell and where the four stages occur in the plant cell. 

*(Image of the cell below, click on link)

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Step1: Glycolysis

Glycolysis is the first stage for Cellular Respiration and it occurs in the cytosol of the plant cell. Since Glycolysis is an anaerobic process and doesn’t require oxygen then glycolysis can still take place because of fermentation. Fermentation is an anaerobic pathway that can be used if there is no oxygen in order to break down glucose. The cytosol is fluid in the cell that is outside of the mitochondria and outside of the outer membrane of the mitochondria. Glycolysis rearranges the bonds in the glucose molecules and releases energy in order to form ATP from ADP and inorganic phosphate which would result in the production of pyruvate.

For Glycolysis, it has glucose first and then NAD+ is reduced in order to form NADH. But if NADH was not present then glycolysis would not be able to continue. Energy from glucose is used to convert ADP into ATP. Then the products of Glycolysis are ATP, NADH and Pyruvate.

Step2: Pyruvate Oxidation

Pyruvate Oxidation occurs in the matrix in the mitochondria. The matrix is the internal space inside the inner membrane. Oxidation means that it loses an electron. Reduction means that it gains an electron. In Pyruvate Oxidation, Pyruvate was produced because of glycolysis. A carboxyl group (COOH) is being removed from the pyruvate (C3H4O3) and releases carbon dioxide. Then NAD+ is being reduced to NADH. Acetyl group (C2H3O) is then transferred and results into 1 Acetyl CoA. The products of Pyruvate Oxidation would be NADH and 2 CO2.