In C4 plants, Calvin cycle

This question was previously asked in
HPSC Assistant Professor 2018 Botany (Official Paper)
View all HPSC Assistant Professor Papers >
  1. occurs in stroma of bundle sheath chloroplasts.
  2. occurs in grana of bundle sheath chloroplasts.
  3. occurs in mesophyll of chloroplasts.
  4. does not occur as CO is fixed mainly by PEP and no CO2 is left for Caivin cycle

Answer (Detailed Solution Below)

Option 1 : occurs in stroma of bundle sheath chloroplasts.
Free
HPSC Asst Prof. Commerce Subject Test 1
1.2 K Users
20 Questions 20 Marks 25 Mins

Detailed Solution

Download Solution PDF

The correct answer is occurs in stroma of bundle sheath chloroplasts.

Concept:

  • C4 plants have a unique mechanism to efficiently fix carbon dioxide (CO2) and minimize photorespiration.
  • The Calvin cycle is a set of biochemical redox reactions that occur in the stroma of chloroplasts in photosynthetic organisms.
  • In C4 plants, the Calvin cycle is spatially separated from the initial CO2 fixation.

Explanation:

  • Option 1: occurs in stroma of bundle sheath chloroplasts: This is the correct answer. In C4 plants, the Calvin cycle takes place in the stroma of bundle sheath chloroplasts. This spatial separation allows C4 plants to efficiently fix CO2 and minimize photorespiration.
  • Option 2: occurs in grana of bundle sheath chloroplasts: This is incorrect. The Calvin cycle does not occur in the grana; it takes place in the stroma. The grana are involved in the light-dependent reactions of photosynthesis.
  • Option 3: occurs in mesophyll of chloroplasts: This is incorrect. In C4 plants, the initial CO2 fixation occurs in the mesophyll cells, but the Calvin cycle takes place in the bundle sheath cells.
  • Option 4: does not occur as CO2 is fixed mainly by PEP and no CO2 is left for Calvin cycle: This is incorrect. While it is true that CO2 is initially fixed by phosphoenolpyruvate (PEP) in the mesophyll cells, the CO2 is then transported to the bundle sheath cells where it enters the Calvin cycle.
Latest HPSC Assistant Professor Updates

Last updated on May 30, 2025

-> The HPSC Assistant Professor Result has been announced for the screening test of Assistant Professor Botany and Zoology posts.

-> The HPSC Assistant Professor Subject Knowledge Test is scheduled on various days between 25th April to 31st August 2025, and the Screening Test will be conducted between 27th April to 29th June 2025.

-> The Skill Test (Fine Arts & Music) was conducted from 4th to 12th April 2025.

-> HPSC Assistant Professor Notification (2024) was released for 2424 vacancies.

-> The commission has decided to conduct the Exams through a Screening Test followed by a Subject Knowledge Test (87.5% weightage) and Interview (12.5 % weightage).

-> Candidates who have completed their Post Graduation are eligible to apply for the post.

-> After getting a successful selection, the candidates will receive a decent salary range between Rs. 57,700 - Rs. 1,82,400.

More Photosynthesis Questions

More System Physiology Plant Questions

Get Free Access Now
Hot Links: master teen patti teen patti download teen patti master plus teen patti winner teen patti gold