The following compounds are intermediates in the Pathway of photorespiration
I. phosphglycolate II. serine III.glyoxylate IV. glycine
The correct sequence their appearance in the pathway is

Options

A. I, II, III, IV
B. I, III, IV, II
C. II, I, III, IV
D. II, I, IV, III

Answer

To determine the correct sequence of the intermediates in the pathway of photorespiration, we need to understand the order in which these compounds appear during the process. Here’s a step-by-step breakdown of the sequence:

### Step 1: Identify the starting point of photorespiration
- The process begins with the reaction of ribulose bisphosphate (RuBP) with oxygen, leading to the formation of phosphoglycolate and phosphoglyceric acid (PGA).

**Hint:** Remember that photorespiration starts with RuBP and oxygen.

### Step 2: First intermediate formed
- The first intermediate formed in the pathway is **phosphoglycolate**.

**Hint:** Phosphoglycolate is the first product when RuBP reacts with oxygen.

### Step 3: Next intermediate in the pathway
- Phosphoglycolate is then converted into **glycolate**.

**Hint:** Glycolate is formed directly from phosphoglycolate.

### Step 4: Formation of glyoxylate
- Glycolate is subsequently converted into **glyoxylate**.

**Hint:** Glyoxylate is a product formed after glycolate.

### Step 5: Formation of glycine
- Glyoxylate is further converted into **glycine**.

**Hint:** Glycine is derived from glyoxylate in the pathway.

### Step 6: Formation of serine
- Finally, glycine is converted into **serine**.

**Hint:** Serine is the last intermediate formed from glycine in this sequence.

### Conclusion: Correct sequence of intermediates
- Based on the above steps, the correct sequence of intermediates in the pathway of photorespiration is:
1. Phosphoglycolate
2. Glyoxylate
3. Glycine
4. Serine

Thus, the correct answer is the second option, which corresponds to the sequence: **I. phosphglycolate, III. glyoxylate, IV. glycine, II. serine**.

### Final Answer:
The correct sequence of their appearance in the pathway is: **I, III, IV, II**.