The key difference between bacteriochlorophyll and chlorophyll is that the anoxygenic phototrophs, such as purple bacteria, heliobacteria and green sulfur bacteria, etc. have bacteriochlorophylls, while oxygenic phototrophs such as green plants, algae and cyanobacteria have chlorophylls.
There are two types of photosynthesis; oxygenic photosynthesis and anoxygenic photosynthesis. There are also two types of photosynthetic pigments as chlorophyll and bacteriochlorophyll. Oxygenic phototrophs have chlorophyll whereas anoxygenic phototrophs have bacteriochlorophyll. Bacteriochlorophyll and chlorophyll are similar in the overall structure. But they differ in the substitutions around the ring and in the length and substitutions on the phytol tail. There are four types of chlorophylls while there are seven types of bacteriochlorophylls.
CONTENTS
1. Overview and Key Difference
2. What is Bacteriochlorophyll
3. What is Chlorophyll
4. Similarities Between Bacteriochlorophyll and Chlorophyll
5. Side by Side Comparison – Bacteriochlorophyll vs Chlorophyll in Tabular Form
6. Summary
What is Bacteriochlorophyll?
Bacteriochlorophyll is a photosynthetic pigment found in phototrophic bacteria such as purple bacteria, heliobacteria and green sulfur bacteria, etc. This pigment participates in anoxygenic photosynthesis. In other words, bacteriochlorophyll involves in the anoxygenic photosynthesis, which does not produce oxygen. There are seven variants of bacteriochlorophylls as a, b, c, d, e, cs and g.
Figure 01: Bacteriochlorophyll
Bacteriochlorophylls are able to absorb energy from light. The overall structure of bacteriochlorophyll is similar to chlorophyll. However, the difference is in substitutions around the ring and in the length and substitutions on the phytol tail. Bacteriochlorophylls capture long-wavelength absorption maximum in the infrared wavelength range.
What is Chlorophyll?
Chlorophyll is the primary pigment of photosynthetic organisms, including plants and algae. It is a green colour pigment capable of capturing light energy from sunlight. Actually, chlorophyll refers to a family of plant pigments. It consists of several chlorophyll pigments, but chlorophyll a and b are the common pigments.
Figure 02: Chlorophyll
Chlorophyll molecules are composed of carbon, hydrogen, nitrogen, and oxygen. These elements are built around the central metallic ion magnesium. Chlorophylls absorb yellow and blue colour wavelengths from the electromagnetic radiation and reflect green. So, this is the reason why they are visible in green colour.
What are the Similarities Between Bacteriochlorophyll and Chlorophyll?
- Bacteriochlorophyll and chlorophyll are two types of photosynthetic pigments.
- They are found in photoautotrophs.
- Both types of pigments can capture and absorb light energy and produce ATP.
- Their overall structures are similar.
- They both have a distinctive tetrapyrrole ring with an Mg2+ in the centre and a long 20-carbon phytol tail.
What is the Difference Between Bacteriochlorophyll and Chlorophyll?
Bacteriochlorophyll is a photosynthetic pigment found in prokaryotic photosynthetic bacteria or phototrophic bacteria. In contrast, chlorophyll is a photosynthetic pigment found in plants, algae and cyanobacteria. Therefore, this is the key difference between bacteriochlorophyll and chlorophyll.
Moreover, another significant difference between bacteriochlorophyll and chlorophyll is that the bacteriochlorophylls participate in anoxygenic photosynthesis; hence, it does not produce oxygen. On the other hand, chlorophylls participate in oxygenic photosynthesis and produce oxygen. Also, there are four types of chlorophylls while there are seven types of bacteriochlorophylls.
Below infographic tabulates the difference between bacteriochlorophyll and chlorophyll.
Summary – Bacteriochlorophyll vs Chlorophyll
Bacteriochlrophyll and chlorophyll are two types of natural pigments. In fact, they are photosynthetic pigments. Bacteriochlorophylls are found in phototrophic bacteria or anoxygenic phototrophs such as purple bacteria, heliobacteria and green sulfur bacteria, etc. Meanwhile, chlorophylls are found in oxygenic phototrophs such as plants, algae and cyanobacteria. Also, there are four types of chlorophylls, while there are seven types of bacteriochlorophylls. So, this is the difference between bacteriochlorophyll and chlorophyll.
Reference:
Image Courtesy:
1. “Bacteriochlorophyll a.mol” By A5b – Own work, redraw of this (CC BY 3.0) via Commons Wikimedia
2. “Chlorophyll a structure” By Yikrazuul – Own work (Public Domain) via Commons Wikimedia
