Question
What are the different steps of pathway?
✓
Answer
Steps of C4, pathway:
- The primary CO2 acceptor is a 3-carbon molecule phosphoenol pyruvate (PEP) and is present in the mesophyll cells. The enzyme responsible for this fixation is PEP carboxylase or PEPcase. It is important to register that the mesophyll cells lack RuBisCO enzyme. The C4, acid OAA is formed in the mesophyll cells.
- It then forms other 4-carbon compounds like malic acid or aspartic acid in the mesophyll cells itself, which are transported to the bundle sheath cells. In the bundle sheath cells these C4 acids are broken down to release CO2 and a 3-carbon molecule.
- The 3-carbon molecule is transported back to the mesophyll where it is converted to PEP again, thus, completing the cycle.
- The CO2 released in the bundle sheath cells enters the C3 or the Calvin pathway, a pathway common to all plants. The bundle sheath cells are rich in an enzyme Ribulose bisphosphate carboxylase-oxygenase (RuBisco), but lack PEPcase. Thus, the basic pathway that results in the formation of the sugars, the Calvin pathway, is common to the C3 and C4 plants.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
What are ribozymes? Describe in detail the nomenclature and classification of enzymes.
You have learnt that a characteristic feature of endocrine system is the presence of feed back loops. By this what is meant if hormone A stimulates gland ‘X’ to secrete hormone B, the production of ‘A’ could be modified when the level of B changes in our blood. An example is the relation between hormones LH and estrogen (E2). An old woman exhibits the following features. High levels of LH in blood but low levels of E2 in the blood. Another woman exhibits high level of LH in blood and also high level of E2 in the blood. Where is the defect in both these women? Provide suitable diagram to support this answer.
Describe the structure of skeletal muscle.
What conditions enable RuBisCO to function as an oxygenase? Explain the ensuing process.
What are suicide bags? Describe its structure and function in detail.
Compare C3 and C4 plants on various parameters.
Does pyruvic acid enter the Krebs' cycle directly?
Draw a picture and describe Meiosis-1 and Meiosis-II
Trunks of some of the aged tree species appear to be composed of several fused trunks. Is it a physiological or anatomical abnormality? Explain in detail.
Give the biochemical composition of plasma membrane. How are lipid molecules arranged in the membrane?