Formation of ATP in photosynthesis and respiration in an oxidation process which utilises the energy from:-

Options

A. cytochromes
B. ferredoxin
C. electrons
D. carbon dioxide

Explanation

### Step-by-Step Solution

1. **Understanding ATP Formation**: ATP (Adenosine Triphosphate) is a crucial energy currency in both photosynthesis and cellular respiration. The formation of ATP involves an energy input, which is derived from different sources in these two processes.

2. **Photosynthesis Process**: In photosynthesis, light energy is captured by chlorophyll and used to excite electrons. This process occurs in the thylakoid membranes of chloroplasts. The excited electrons are then transferred through a series of proteins known as the electron transport chain.

3. **Electron Transport Chain**: As the electrons move through the chain, they release energy, which is used to pump hydrogen ions (H+) from the stroma into the thylakoid lumen. This creates a proton gradient across the thylakoid membrane.

4. **Formation of ATP in Photosynthesis**: The proton gradient generated drives ATP synthesis through a process called photophosphorylation. ATP synthase, an enzyme located in the thylakoid membrane, utilizes the flow of hydrogen ions back into the stroma to convert ADP and inorganic phosphate (Pi) into ATP.

5. **Respiration Process**: In cellular respiration, particularly in the mitochondria, the process is similar but involves the oxidation of glucose. Electrons are transferred from NADH and FADH2 (produced during glycolysis and the Krebs cycle) through the electron transport chain.

6. **Electron Transport in Respiration**: Similar to photosynthesis, the movement of these electrons releases energy, which is used to pump hydrogen ions from the mitochondrial matrix into the intermembrane space, creating a proton gradient.

7. **Formation of ATP in Respiration**: The ATP synthase enzyme in the inner mitochondrial membrane uses the energy from the flow of hydrogen ions back into the matrix to synthesize ATP from ADP and Pi, a process known as oxidative phosphorylation.

8. **Conclusion**: In both photosynthesis and respiration, the formation of ATP is driven by the energy released from excited electrons as they move through the electron transport chain, which ultimately leads to the creation of a proton gradient that powers ATP synthesis.

### Final Answer
The formation of ATP in photosynthesis and respiration utilizes energy from **electrons**.

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