The enzyme needed in biological system for joining two molecules is called

Options

A. Lyase
B. Diastase
C. Polymerase
D. Hydrolase.

Answer

To answer the question "The enzyme needed in biological systems for joining two molecules is called", we will analyze each option provided and determine which enzyme is responsible for this function.

### Step-by-Step Solution:

1. **Understanding Enzymes**: Enzymes are biological catalysts that speed up chemical reactions in living organisms. They facilitate various biochemical processes, including the joining and breaking of molecular bonds.

2. **Analyzing the Options**:
- **Option 1: Lyase**: Lyases are enzymes that catalyze the addition or removal of groups to form double bonds or break down compounds without hydrolysis. They do not primarily function to join two molecules.
- **Option 2: Diastase**: Diastase is an enzyme that breaks down starch into sugars, specifically maltose into glucose. This enzyme is involved in the breakdown of molecules, not the joining.
- **Option 3: Polymerase**: Polymerases are enzymes that synthesize long chains or polymers by joining monomers together. They are essential for processes like DNA and RNA synthesis, where nucleotides are joined to form nucleic acids.
- **Option 4: Hydrolase**: Hydrolases are enzymes that catalyze the hydrolysis of chemical bonds, leading to the breakdown of larger molecules into smaller ones. They do not join molecules.

3. **Identifying the Correct Answer**: Given the functions of the enzymes analyzed, the enzyme that is specifically responsible for joining two molecules together is **Polymerase**. Therefore, the correct answer is **Option 3: Polymerase**.

### Final Answer:
The enzyme needed in biological systems for joining two molecules is called **Polymerase**.

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