#Photosystems

#Biology

#Photosynthesis

Introduction

• Photosystems are functional and structural units of protein complexes involved in photosynthesis, crucial for converting light energy into chemical energy.

• There are 3 Functions for Photosystems :

1. Absorb Energy.

2. Electron Transfer.

3. Energy Production.

• Photosystems are found in the thylakoid membranes of plants, algae, and cyanobacteria. Thylakoid membranes are a part of Chloroplast.

Structure

• There are 2 Parts of Photosystem :

1. Reaction Centre

2. Antenna Complex

Reaction Centre

• The photosynthetic reaction center consists of proteins, pigments, and other co-factors that work together to convert light energy into chemical energy.

• The reaction centre is crucial for the photochemistry process, where light energy excites electrons and drives the process of photosynthesis.

• The photosynthetic reaction centre comprises a chlorophyll pair for oxidation-reduction, antenna chlorophylls, and other pigments for light absorption.

• Protein Complexes It consists of proteins and co-factors that are essential for the energy conversion process during photosynthesis.

Antenna Complex

• The antenna complex, also known as the light-harvesting complex (LHC), is made up of hundreds of chlorophyll molecules and carotenoids that capture light energy.

  
  

• Energy Transfer This complex plays a critical role in photosynthesis by transferring absorbed light energy to the reaction centre chlorophyll-a molecules, facilitating the conversion of light energy into chemical energy.

  
  

• The main component LHCII binds a significant portion of chlorophyll and is essential for the overall efficiency of light absorption in plants.

• The energy collected by the antenna complex is transferred to the reaction centre via resonance energy transfer, where the actual photosynthetic reactions take place.

Types

• There are 2 types of Photosystems :

1. Photosystem I

2. Photosystem II

• PSI - An integral membrane protein complex that transfers electrons from plastocyanin to ferredoxin, ultimately producing NADPH as a hydrogen carrier.

• PSII - Works in tandem with PSI, primarily responsible for splitting water molecules to release oxygen and providing electrons for PSI.

  
  
  
  

The Video