Which one(s) of the following statements is correct?

Options

A. Enzymes accelerate reactions by stabilizing transition state
B. A chemical reaction of substrate to form product goes through a transition state that a higher free energy than either substrate or a product(s)
C. The rate of formation of E-S complex is the same as the rate of breakdown of this complex either to products or back to reactant
D. All

Answer

To determine which of the statements regarding enzymes is correct, we will analyze each option step by step.

### Step 1: Analyze the first statement
**Statement:** Enzyme accelerates the reaction by stabilizing transition state.

**Analysis:** This statement is partially correct. Enzymes do stabilize the transition state, which lowers the activation energy required for the reaction to proceed. However, it is not the only mechanism by which enzymes accelerate reactions.

### Step 2: Analyze the second statement
**Statement:** Enzyme increases the rate of reaction by lowering down the activation energy.

**Analysis:** This statement is correct. Enzymes work by lowering the activation energy of a reaction, which increases the rate at which the reaction occurs. This is one of the fundamental roles of enzymes.

### Step 3: Analyze the third statement
**Statement:** Enzyme increases the rate of reaction by stabilizing transition state.

**Analysis:** Similar to the first statement, this is also partially correct. While stabilizing the transition state does contribute to lowering activation energy, it is not the only factor involved in how enzymes increase reaction rates.

### Step 4: Analyze the fourth statement
**Statement:** A chemical reaction of substrate to form product goes through a transition state that has higher free energy than either substrate or product.

**Analysis:** This statement is correct. The transition state is indeed a high-energy state that is formed during the conversion of substrates to products, and it typically has a higher free energy than both the substrates and the products.

### Step 5: Analyze the fifth statement
**Statement:** Any reaction that binds with enzyme substrate is called enzyme substrate complex.

**Analysis:** This statement is correct. When a substrate binds to an enzyme, the resulting complex is referred to as the enzyme-substrate complex.

### Step 6: Analyze the sixth statement
**Statement:** The rate of formation of enzyme substrate complex is the same as the rate of breakdown of complex.

**Analysis:** This statement is generally correct in the context of enzyme kinetics at equilibrium. At steady state, the rate of formation of the enzyme-substrate complex equals the rate of its breakdown into products and free enzyme.

### Conclusion
After analyzing all the statements, the following are correct:
1. Enzyme increases the rate of reaction by lowering down the activation energy.
2. A chemical reaction of substrate to form product goes through a transition state that has higher free energy than either substrate or product.
3. Any reaction that binds with enzyme substrate is called enzyme substrate complex.
4. The rate of formation of enzyme substrate complex is the same as the rate of breakdown of complex.