During photorespiration, 25% of the carbon is lost in
(a) chloroplast
(b) mitochondria
(c) peroxisome
(d) nucleus

Options

A. chloroplast
B. mitochondria
C. peroxisome
D. nucleus

Answer

To solve the question regarding where 25% of carbon is lost during photorespiration, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Photorespiration**:
- Photorespiration is a process that occurs in plants, particularly in C3 plants, when the concentration of oxygen is higher than that of carbon dioxide. This leads to a wasteful pathway where carbon is lost.

2. **Identify the Key Enzyme**:
- The enzyme involved in photorespiration is ribulose bisphosphate carboxylase/oxygenase (RuBisCO). Under high oxygen conditions, RuBisCO can bind to oxygen instead of carbon dioxide, leading to the production of a compound that ultimately results in carbon loss.

3. **Recognize the Organelles Involved**:
- Photorespiration involves three organelles: chloroplasts, peroxisomes, and mitochondria. The process begins in the chloroplasts, moves to the peroxisomes, and finally involves the mitochondria.

4. **Determine Where Carbon is Lost**:
- During the photorespiration process, carbon is released primarily from the mitochondria. This is where the breakdown of the compounds formed during photorespiration occurs, leading to the loss of carbon.

5. **Select the Correct Option**:
- Given the options:
- (a) chloroplast
- (b) mitochondria
- (c) peroxisome
- (d) nucleus
- The correct answer is (b) mitochondria, as this is where 25% of the carbon is lost during photorespiration.

### Final Answer:
(b) mitochondria