explain c4 pathway
Asked by sreejitakarmakar1999 | 4th Jan, 2019, 09:46: PM
Hatch–Slack Cycle or C4 Cycle
1. The C4cycle is found in tropical and subtropical grasses such as maize, sugarcane, pear, millet, all the other monocots and dicots such asAmaranthusand Euphorbia.
2. C4plants are adapted to overcome photorespiration and deliver CO2directly to theenzyme RuBisCO.
1. Initial Fixation
i. Carbon dioxide is first fixed in the mesophyll cells to form a 3C compound—phosphoenol pyruvic acid (PEP), leading to the formation of a 4C compound, oxaloacetic acid (OAA) which is transaminated to form malic acid or aspartic acid.
ii. Aspartic acid is then transported to bundle sheath cells through plasmodesmata
2. Final Fixation
i. Inside the bundle sheath cells, malic acid is decarboxylated into pyruvic acid and aspartic acid is deaminated into alanine.
ii. CO2released in bundle sheath cells is fixed through the Calvin cycle in which RUBP is the secondary or final acceptor of CO2in C4plants
3. Regeneration of PEP
i. Pyruvic acid or alanine formed in the bundle sheath cells return to the mesophyll cells.
ii. Alanine is deaminated through a transamination reaction to form pyruvic acid.
iii. Pyruvic acid is converted to phosphoenol pyruvic acid and inorganic phosphate with the help of ATP
C4plants require a total of30 ATP and 12 NADPH molecules to synthesise one molecule of glucose from6 molecules of CO2
Answered by Sivanand Patnaik | 5th Jan, 2019, 08:43: PM
- Is photorespiration present at low co2 concentration in c3 and c4 plants?
- Is photorespiration present at low light intensity in c3 and c4 plants? Is photorespiration present at high light intensity in c3 and c4 plants?
- Please answer the following question with explanation
- What is the first stable compound formed from CO2 fixation in C4 plants?
- What is the anatomical structure of the leaves of C4 plants known as?
- Give two examples of C4 plants.
- How can a C4 plant leaf section be distinguished from that of a C3 plant leaf section?
- Which is the primary CO2 acceptor in C4 plants?
- Why does the Calvin cycle not occur in mesophyll cells?
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