Photosynthesis in Prokaryotes - Biology

1. Fundamental Concepts

Definition: Photosynthesis in prokaryotes is the process by which these single-celled organisms convert light energy into chemical energy, primarily using pigments like bacteriochlorophyll.
Types: Prokaryotic photosynthesis can be oxygenic (producing oxygen) or anoxygenic (not producing oxygen).
Examples: Cyanobacteria are examples of oxygenic photosynthetic prokaryotes, while purple bacteria are anoxygenic.

2. Key Concepts

Basic Rule: $${\text{{Light}} \cdot {\text{{Energy}}} + {\text{{CO}}}_2 + {\text{{H}}}_2{\text{{O}}} \rightarrow ({\text{{CH}}}_2{\text{{O}}}) + {\text{{O}}}_2}$$

Diversity in Pigments: Different types of prokaryotes use different pigments to capture light energy.

Application: Understanding prokaryotic photosynthesis helps in biotechnology and environmental studies.

3. Examples

Example 1 (Basic)

Problem: Identify the type of photosynthesis in cyanobacteria.

Step-by-Step Solution:

Cyanobacteria use chlorophyll a, similar to plants, for photosynthesis.
This process produces oxygen as a byproduct.
Therefore, cyanobacteria perform oxygenic photosynthesis.

Validation: Cyanobacteria release oxygen during photosynthesis, confirming they are oxygenic.

Example 2 (Intermediate)

Problem: Write the general equation for anoxygenic photosynthesis in purple bacteria.

Step-by-Step Solution:

Anoxygenic photosynthesis does not produce oxygen.
The general equation involves sulfur compounds instead of water.
The equation is: $${\text{{Light}} \cdot {\text{{Energy}}} + {\text{{CO}}}_2 + {\text{{H}}}_2{\text{{S}}} \rightarrow ({\text{{CH}}}_2{\text{{O}}}) + {\text{{S}}} + {\text{{H}}}_2{\text{{O}}}$$

Validation: The equation correctly shows that sulfur is used instead of water and no oxygen is produced.

4. Problem-Solving Techniques

Visual Strategy: Use diagrams to represent the flow of energy and electrons in photosynthesis.
Error-Proofing: Always check if the reaction balances on both sides in terms of atoms and charges.
Concept Reinforcement: Relate the concepts of photosynthesis in prokaryotes to their ecological roles and impacts.