Similarities and Difference between C3 and C4 Plants – A Comparison Table


C3 vs C4 Plants Comparison

Similarities and Difference between C3 and C3 Plants
(C3 plants vs C4 plants – A Comparison Table)

Green plants are unique to possess the ability to fix light energy from sunlight through a process called photosynthesis. The photosynthesis essential involves the synthesis of carbohydrates with atmospheric carbon dioxide, water and energy obtained from the sunlight. The process of photosynthesis in plants is completed in two broad steps, a light dependent ‘Light Reaction’ and a light independent ‘Dark Reaction”. In the light reaction, the chlorophyll molecules in the plants absorb energy from sunlight and synthesize energy rich chemical molecules such as ATP and reduced coenzymes (NADPHH+). In the dark reaction, these energy rich molecules are used up for the synthesis of carbohydrates with carbon dioxide. There are essentially three different types of dark reaction pathways are operated in different plants on earth and they are named on the basis of the components of these pathways. They are C3 plants, C4 plants and CAM plants. The present post describes the similarities and differences between C3 plants and C4 Plants.

C3 Plants: Plants which uses C3 cycle (Calvin cycle) of dark reaction of photosynthesis. C3 cycle is the first described dark reaction pathway. Majority of the plants (~95%) on earth are C3 type. The first stable product formed in C3 cycle is a three carbon (3C) compound, hence the name. The photosynthetic efficiency of C3 plants is comparatively less due the high rate or photorespiration. For a considerable period of time, the C3 cycle was thought to be the only dark reaction pathway in plants.

C4 Plants: These plants in addition to C3 cycle, uses an additional dark reaction pathway called C4 cycle. Very few plants (~5%) on earth are C4 type. The first stable product formed in C4 cycle is a four carbon (4C) compound, hence the name. The photosynthetic efficiency of C4 plants is very high due to the absence of photorespiration. 

Similarities between C3 and C4 Plants

@. Both C3 and C4 are types of dark reactions of photosynthesis.

@. Both C3 and C4 plants fix energy from sunlight.

@. Both C3 and C4 plants synthesize carbohydrates.

@. The general equation of photosynthesis (6CO2 + 12H2O → 6C6H12O6 + 6O2 + 6H2O) is similar in both C3 and C4 plants.

@. Both C3 and C4 plants require 6 molecules of CO2 and 12 molecules of water to synthesis one molecule of glucose.

@. The carbohydrate product of both C3 and C4 cycle is a three-carbon sugar phosphate molecules called Glyceraldehyde 3 phosphate (G3P).

@. Both C3 and C4 plants requires chloroplasts for doing photosynthesis.

@. The light reaction of photosynthesis is similar in both C3 and C4 plants.

@. RuBP can accept CO2 in both C3 and C4 plants.

Difference between C3 and C4 Plants

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Difference between C3 and C4 Cycles of Photosynthesis in Plants


C3 vs C4 Cycles of Photosynthesis

Similarities and Differences between C3 and C4 Cycles: A Comparison Table
(Calvin Cycles Vs Hatch and Slack Cycle)

Photosynthesis is one of the vital events in the earth in which the green plants fix the energy from the sunlight and synthesis nutrients with carbon dioxide and water. Almost all living things on earth, either directly or indirectly, depend on photosynthesis for energy. The process of photosynthesis in plants is completed in two major pathways, a light dependent ‘Light Reaction’ and a light independent ‘Dark Reaction’. In the light reaction, the chlorophyll molecules in the plants absorb energy from sunlight and synthesize energy rich chemical molecules such as ATP and reduced coenzymes (NADPHH+). In the dark reaction, this energy rich molecules are used up for the synthesis of carbohydrates from carbon dioxide. The first describe dark reaction pathway, better known as Calvin cycle (Melvin Calvin who discovered this pathway), is called C3 cycle. For a considerable period of time, the Calvin cycle (C3 cycle) was thought to be the only dark reaction pathway in plants. Later, a new pathway of dark reaction called Hatch and Slack pathway or C4 cycle was described in some plants. Both these cycles (C3 and C4 cycles) show many similarities and differences. The present post describes the similarities and differences between C3 cycle and C4 cycle of the dark reaction of photosynthesis.

Similarities between C3 cycle and C4 cycle

Ø  Both C3 and C4 cycles are pathways of dark reaction of photosynthesis.

Ø  Both are light independent reactions.

Ø  Both C3 and C4 cycle requires energy from ATP or reduced coenzymes.

Ø  Both C3 and C4 plants accept carbon dioxide to perform dark reaction.

Ø  End products of C3 and C4 cycle are similar.

Ø  Both C3 and C4 cycle requires RuBP and RUBISCO to complete the pathway.

Difference between C3 cycle and C4 cycle:

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