What is the Difference Between Ubiquinone and Plastoquinone?

Ubiquinone and plastoquinone are both prenylquinones that function as electron transporters in plants, but they have distinct roles and structures. The main differences between ubiquinone and plastoquinone are:

1. Function: Ubiquinone acts as an electron carrier in the electron transport chain of oxidative phosphorylation, while plastoquinone acts as an electron carrier in the electron transport chain of oxygenic photosynthesis.
2. Structure: Both ubiquinone and plastoquinone consist of an active benzoquinone ring attached to a polyisoprenoid side chain. The length of the polyisoprenoid side chain determines the type of ubiquinone or plastoquinone. Ubiquinone usually includes nine or ten units of isoprenoid side chain, while plastoquinone can have different side chain lengths, such as PQ-3 with three isoprenyl side units.
3. Light Dependence: Ubiquinone is light-dependent, while plastoquinone is light-independent.

In summary, ubiquinone and plastoquinone are both important prenylquinones in plants, but they have different functions and structures. Ubiquinone is involved in the electron transport chain of oxidative phosphorylation, while plastoquinone plays a role in the electron transport chain of oxygenic photosynthesis.

Comparative Table: Ubiquinone vs Plastoquinone

Ubiquinone and plastoquinone are both prenylquinones that function as electron carriers in the electron transport chain, contributing to the growth and development of plants. Here is a table summarizing the differences between ubiquinone and plastoquinone:

Despite their similarities, ubiquinone and plastoquinone have distinct roles and locations within the plant cell. Ubiquinone is present in the inner membrane of the mitochondria and acts as an electron carrier in the electron transport chain of oxidative phosphorylation, while plastoquinone is present on the thylakoids of chloroplast and acts as an electron carrier in the electron transport chain of light-dependent reactions.