How many chiral centres are present in Threonine

Answer

To determine the number of chiral centers in Threonine, we can follow these steps:

### Step 1: Understand the Structure of Threonine
Threonine is an alpha-amino acid, which means it has a central carbon atom (the alpha carbon) that is bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (-H), and a side chain (R group).

### Step 2: Identify the Side Chain of Threonine
The side chain of Threonine is -CH(OH)-CH3. This means that the side chain contains a hydroxyl group (-OH) and a methyl group (-CH3).

### Step 3: Draw the Structure
The structure of Threonine can be represented as follows:
```
H
|
H2N-C-COOH
|
CH(OH)
|
CH3
```

### Step 4: Determine Chiral Centers
A chiral center (or chiral carbon) is a carbon atom that is attached to four different groups.

- The alpha carbon (C) in Threonine is attached to:
1. Amino group (-NH2)
2. Carboxyl group (-COOH)
3. Hydroxyl group (-OH)
4. Methyl group (-CH3)

Since all four substituents on the alpha carbon are different, it is a chiral center.

### Step 5: Check for Additional Chiral Centers
Next, we check if there are any other chiral centers in the molecule. The carbon in the side chain (the one attached to -OH and -CH3) is also a chiral center because:
- It is attached to:
1. Hydroxyl group (-OH)
2. Methyl group (-CH3)
3. The alpha carbon (C)
4. A hydrogen atom (-H)

Since this carbon is also attached to four different groups, it is another chiral center.

### Step 6: Count the Chiral Centers
In total, we have identified:
1. One chiral center at the alpha carbon.
2. One chiral center at the carbon in the side chain.

Thus, Threonine has **two chiral centers**.

### Final Answer
Threonine has **2 chiral centers**.

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