C3 & C4 Photosynthetic Mechanisms Assignment

Introduction

Description of the photosynthetic mechanism of C4 plants:

C4 photosynthesis is a two-stage process in which a four-carbon compound is produced. The photosynthetic process occurs in the chloroplast of a thin-walled mesophyll cell. Once created, the compound is pumped into a thick-walled bundle sheath cell, where it is split into carbon dioxide and a three-carbon compound. The carbon dioxide then undergoes the Calvin cycle that makes the C4 produce a higher concentration of carbon, making them able to survive in habitats with low light and water.

Description of the photosynthetic mechanism of C3 plants:

Photosynthesis in the C3 Is a three stage process, where in the first stage carbon dioxide is diffused into the stroma of the chloroplast in the mesophyll cells is added to the five- carbon acceptor RuBp, producing two molecules on PGA. Both the Pga molecules undergoes further reactions to produce the three-carbon triose phosphate sugar glyceraldehyde-3-phosphate. Some molecules of G3P go through further reactions which result to the reformation of RuBP, the CO2 acceptor in the C3 cycle. To complete the process of photosynthesis, the other molecules of G3P leave the cycle and proceed to a series of reactions to form glucose and other sugars, starch, and other organic compounds.

Task

C4 plant photosynthetic pathway diagram:

C3 plant photosynthetic pathway diagram:

CAM diagram

 

Process

Five species that undergo C4 photosynthesis:

  • Crabgrass

  • Corn

  • Sugarcane

  • Sorghum

  • Amaranth

Five species that undergo C3 photosynthesis:

  • wheat 
  • rice
  • barley
  • spinach
  • ​​​​​​​soy beans 

Evaluation

Environmental conditions in which C4 plants are found:

C4 plants are found in ecosystems with hot and dry temperatures, high light, low water, and also low nutrients. These kinds of plants make a lot of energy during the process of C4 photosynthesis.

Environmental conditions in which C3 plants are found:

C3 plants can be found in the more dry, moister environments in our ecosystems and more cooler to average temperatures. 

Conclusion

Similarities between C3 & C4:

  • Both synthesis carbohydrates

  • Both require 6 molecules of CO2 and 12 molecules of water to synthesis one molecule of glucose

  • Both types of plant require chloroplast to photosynthesis

RUBP can accept CO2 in both C3 and C4 plants

 

Differences between C3 & C4:

  • C3 plants are are cool season plants, commonly seen in cool, wet areas.

  • C4 plants are warm season plants, commonly seen in dry areas.

  • In C3 plants the bundle sheath cells do not contain chloroplast

  • In C4 plants  the bundle sheath cells does contain chloroplast

  • In C3 plants carbon fixation takes place at one place

  • In C4 plants carbon fixation occurs twice (once in the mesophyll cell and once in the bundle sheath cell)

  • C3 plants are less efficient in photosynthetic energy fixation

  • C4 plants are more efficient in photosynthesis