The energy that is released by the hydrolysis of ATP by actin is used for :

Options

A. actin filaments assembly
B. actin filaments disassembly
C. actin-myosin assembly
D. actin-myosin disassembly

Answer

To answer the question regarding the energy released by the hydrolysis of ATP by actin, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding ATP Hydrolysis**:
- ATP (adenosine triphosphate) is a molecule that stores energy in its high-energy phosphate bonds. When ATP is hydrolyzed, it breaks down into ADP (adenosine diphosphate) and an inorganic phosphate (Pi), releasing energy in the process.

**Hint**: Remember that ATP is the primary energy currency of the cell, and its hydrolysis is a key reaction that powers many cellular processes.

2. **Role of Actin and Myosin**:
- Actin is a protein that forms filaments and is a crucial component of muscle contraction. Myosin is another protein that interacts with actin to facilitate movement. The interaction between actin and myosin is essential for muscle contraction.

**Hint**: Think of actin and myosin as the two main players in muscle contraction, where myosin pulls on actin filaments to shorten the muscle.

3. **Energy Utilization in Muscle Contraction**:
- The energy released from ATP hydrolysis is utilized by myosin to perform work. Specifically, it allows myosin to "walk" along the actin filaments, causing the filaments to slide past each other. This sliding action leads to muscle contraction.

**Hint**: Visualize the sliding filament model of muscle contraction, where myosin heads pull on actin filaments to shorten the muscle.

4. **Actin Filament Assembly**:
- The hydrolysis of ATP is also involved in the assembly of actin filaments. ATP-bound actin monomers are added to the growing filament, and the hydrolysis of ATP to ADP promotes the stability and assembly of these filaments.

**Hint**: Consider how energy is needed not just for movement but also for building structures within the cell, like actin filaments.

5. **Conclusion**:
- Therefore, the energy released by the hydrolysis of ATP by actin is primarily used for the assembly of actin filaments and the contraction of muscles through the interaction with myosin.

**Hint**: Summarize that ATP hydrolysis is crucial for both the assembly of actin filaments and the contraction process, making it essential for locomotion and muscle function.

### Final Answer:
The energy released by the hydrolysis of ATP by actin is used for the assembly of actin filaments and muscle contraction.