How many additional ATPs are required in `C_(4)` plants as compared to `C_(3)` plants to synthesize 2 molecules of hexose sugar ?

Options

A. 12 ATP
B. 24 ATP
C. 36 ATP
D. 48 ATP

Answer

To determine how many additional ATPs are required in C4 plants compared to C3 plants to synthesize 2 molecules of hexose sugar, we will follow these steps:

### Step 1: Understand ATP requirements for C3 plants
For C3 plants, it takes 18 ATP molecules to synthesize one molecule of glucose (hexose sugar). Since we are interested in synthesizing 2 molecules of glucose, we need to calculate the total ATP required.

**Calculation:**
- ATP for 1 glucose = 18 ATP
- ATP for 2 glucose = 18 ATP × 2 = 36 ATP

### Step 2: Understand ATP requirements for C4 plants
For C4 plants, the ATP requirement is different. It takes 30 ATP molecules to synthesize one molecule of glucose. Therefore, for 2 molecules of glucose, we calculate the total ATP required.

**Calculation:**
- ATP for 1 glucose = 30 ATP
- ATP for 2 glucose = 30 ATP × 2 = 60 ATP

### Step 3: Calculate the additional ATP required
Now, we need to find the difference in ATP requirements between C4 and C3 plants for synthesizing 2 molecules of glucose.

**Calculation:**
- Additional ATP = ATP (C4) - ATP (C3)
- Additional ATP = 60 ATP (C4) - 36 ATP (C3) = 24 ATP

### Conclusion
Thus, C4 plants require an additional 24 ATP molecules compared to C3 plants to synthesize 2 molecules of hexose sugar.

### Final Answer
24 additional ATPs are required in C4 plants as compared to C3 plants to synthesize 2 molecules of hexose sugar.

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