Chapter 13, Problem 4Q

Summary Introduction

To review:

Role of PS II (photosystem two) and cause of light-induced damageto the D1 polypeptide.

Introduction:

Excessive light is known to cause photoinhibition in plants. Plants have specialized repair mechanisms present in photosystem II (PS II), which helps in their survival. The D1 polypeptide is repaired immediately after damage. PSII is a pigment–protein complex that consists of multiple components thatplaya considerable role in the splitting of water molecule, evolution of oxygen, and reduction of plastoquinone (PQ). It has core proteins, oxygen-evolving complex, and light-harvesting complex proteins. Photoinhibition is a process duringwhich photosynthesis is inhibited due to the excessive presence of light in the atmosphere. The photosynthetic capacity of the plant is reduced due to sensitivity from light.