How many additional ATP are used during synthesis of two
molecules of hexose sugar in maize than tomato ?

Options

A. 12
B. 36
C. 8
D. 24

Answer

To solve the question of how many additional ATP are used during the synthesis of two molecules of hexose sugar in maize compared to tomato, we can follow these steps:

### Step 1: Identify the pathways of sugar synthesis
- Understand that there are two main pathways for sugar synthesis in plants: the C3 pathway and the C4 pathway.
- C3 pathway is primarily found in dicots, while the C4 pathway is found in monocots.

### Step 2: Determine the ATP requirement for each pathway
- The synthesis of one molecule of hexose sugar in the C3 pathway (dicots) requires 18 ATP.
- The synthesis of one molecule of hexose sugar in the C4 pathway (monocots) requires 30 ATP.

### Step 3: Identify the plants involved
- Tomato is a dicotyledon plant, which uses the C3 pathway.
- Maize is a monocotyledon plant, which uses the C4 pathway.

### Step 4: Calculate the ATP used for one molecule of hexose sugar
- For tomato (C3 pathway): 18 ATP for one molecule of hexose.
- For maize (C4 pathway): 30 ATP for one molecule of hexose.

### Step 5: Calculate the difference in ATP usage for one molecule
- The difference in ATP usage for one molecule of hexose sugar between maize and tomato is:
\[ 30 \text{ ATP (maize)} - 18 \text{ ATP (tomato)} = 12 \text{ ATP} \]

### Step 6: Calculate the total ATP for two molecules
- Since the question asks for the synthesis of two molecules of hexose sugar, we multiply the difference by 2:
\[ 12 \text{ ATP} \times 2 = 24 \text{ ATP} \]

### Conclusion
- Therefore, the additional ATP used during the synthesis of two molecules of hexose sugar in maize compared to tomato is **24 ATP**.