Difference Between Bacterial Photosynthesis and Plant Photosynthesis

Photosynthesis is a crucial process involving solar energy to convert carbon dioxide and water into oxygen and glucose. Both plants and bacteria undergo photosynthesis, but the structures and mechanisms involved vary.

Table of Contents:

What is Photosynthesis?
Bacterial Photosynthesis
Plant Photosynthesis
Bacterial Photosynthesis vs. Plant Photosynthesis
Practice Problems
Frequently Asked Questions

What is Photosynthesis?

Light is transformed into chemical energy stored as glucose (sugar). Inorganic compounds like carbon dioxide, water, and sunlight produce oxygen, water, and glucose. Using carbon, photosynthetic organisms can generate organic molecules like carbohydrates, proteins, and lipids and construct their biological mass. In many organisms, oxygen is produced as a byproduct during photosynthesis and is utilised for cellular respiration.

Many living organisms rely on photosynthesis to acquire their nutrition directly or indirectly. Animals, fungi, and most bacteria are not capable of engaging in photosynthesis and produce their organic compounds from inorganic compounds that are referred to as heterotrophs. To obtain their substances, they rely on autotrophs to generate their nutrition.

Bacterial Photosynthesis

Cyanobacteria, or blue-green algae, is a class of bacteria that can engage in photosynthesis. They do not possess specialised organelles like chloroplasts in comparison to plants. However, they have their own photosynthetic machinery. On the other hand, it is housed in sophisticated cell regions known as thylakoids, consisting of chlorophyll that absorbs light energy.

Variations in Pigments

Distinct types of chlorophyll pigments are used by bacteria, such as Phycobilin and chlorophyll a. Similar to the plant’s chlorophyll, chlorophyll a is capable of absorbing light energy in the red or blue region of the spectrum. At the same point, Phycobilin enhances the wavelength range by the light absorption in the blue and green spectrum.

No Oxygen Production

Oxygen is not generated as the byproduct of bacterial photosynthesis. However, compounds of sulphur and molecular hydrogen are released. The reason behind this phenomenon is the inability to split water molecules in bacteria as it does in plants.

Plant Photosynthesis

Photosynthesis is performed through the specialised organelle called chloroplast in plants. It consists of pigments of chlorophyll that have the ability to absorb light energy. The process involves multiple distinct steps that include both light-dependent and light-independent reactions.

Production of Oxygen

Unique place called chloroplast is the only region responsible for the photosynthetic process in plants. The plant cell contains an intricate interior structured organelle involving outer and inner membranes along with thylakoids, an interconnected system of flattened sacs. The crucial elements and chlorophyll required necessarily for the light-dependent reactions are found in thylakoids.

Structure of Chloroplast

Plant photosynthesis involves the production of oxygen, which contributes to atmospheric oxygen and sustains aerobic life on the Earth. The oxygen formed as a byproduct due to water splitting in a light-dependent reaction.

Carbon Fixation

Carbon fixation is a process in which light-independent reactions like the Calvin cycle involve the utilisation of energy produced by the light-dependent reactions to transform carbon dioxide into glucose (sugar). The process takes place in the stroma, which is a fluid-filled area in chloroplasts. Glucose is said to be the main source of energy in the plant body. Also, glucose helps plants to generate other organic molecules.

Bacterial Photosynthesis vs. Plant Photosynthesis

Differences Based On	Bacterial Photosynthesis	Plant Photosynthesis
Photosynthetic pigment	Bacteriochlorophyll	Chlorophyll a and Chlorophyll b
Production of Oxygen	No production of oxygen takes place.	Production of oxygen takes place.
Wavelength	The absorption of light by bacteriochlorophyll is approximately 800 nm	The absorption of light ranges from 400 to 750 nm.
Photosynthetic pigment location	The photosynthetic pigment is present in the plasma membrane folds.	The photosynthetic pigment is present in the double membrane-enclosed grana of chloroplasts.
Occurrence	Cyanobacteria, acidobacteria, heliobacteria, purple bacteria, and phototrophic.	Algae and all types of plants.
Phosphorylation type	Non-cyclic	Cyclic
Reducing Agent	H₂S or other organic compounds are utilised as reducing agents.	H₂O is utilised as a reducing agent.

Practice Problems

Q1. In bacteria, the photosynthetic pigment required is

A. Chlorophyll a
B. Bacteriochlorophyll
C. Chlorophyll b
D. All of the above

Ans. B. Bacteriochlorophyll

Bacteriochlorophyll is the photosynthetic pigment involved in bacterial photosynthesis.

Q2. The wavelength of the light absorbed by Bacteriochlorophyll is

A. ~800 nm
B. ~450 nm
C. ~880 nm
D. ~480 nm

Ans. A. ~800 nm

The wavelength of the light absorbance by Bacteriochlorophyll is ~800 nm in bacterial photosynthesis.

Q3. Non-cyclic phosphorylation is prevalent in

A. bacterial photosynthesis
B. fungi
C. plant photosynthesis|
D. All of the above

Ans. A. bacterial photosynthesis

Photosynthesis in bacteria involves non-cyclic phosphorylation.

Frequently Asked Questions

Q1. State one difference between photosynthetic and non-photosynthetic organisms.
Answer : Unlike photosynthetic organisms, non-photosynthetic organisms do not possess chloroplast and cannot photosynthesise. As a result, they rely on other organisms to gain their energy.

Q2. What are aerobic and anaerobic conditions?
Answer : The presence of free oxygen in the environment is called aerobic conditions. On the other hand, the absence of free oxygen in the environment is referred to as an anaerobic condition. Still, it consists of atomic oxygen bound in the compounds like sulfites, nitrites, and nitrates.

Q3. Why is light energy converted into chemical energy in plants and living organisms?
Answer : Light energy gets converted into chemical energy by green plants and certain organisms to synthesise their food and produce energy.