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: Identify the Structure of Threonine
Threonine is an amino acid with the following structure:
- It has a central carbon (the alpha carbon) that is bonded to:
- An amino group (-NH2)
- A carboxyl group (-COOH)
- A hydroxyl group (-OH)
- A side chain (which is a carbon chain)

### Step 2: Analyze the Central Carbon
The central carbon (alpha carbon) is crucial for identifying chiral centers. A chiral center is defined as a carbon atom that is attached to four different groups.

### Step 3: Check the Groups Attached to the Alpha Carbon
For Threonine, the groups attached to the alpha carbon are:
1. Amino group (-NH2)
2. Carboxyl group (-COOH)
3. Hydroxyl group (-OH)
4. Side chain (which is a carbon chain)

Since all four groups attached to the alpha carbon are different, this carbon is indeed a chiral center.

### Step 4: Identify Any Additional Chiral Centers
Next, we need to check if there are any other carbon atoms in the structure of Threonine that could also be chiral centers.

In Threonine, there is another carbon in the side chain. The side chain of Threonine is -CH(OH)-CH3. The carbon that is attached to the hydroxyl group (-OH) and the methyl group (-CH3) is also bonded to different groups:
1. Hydroxyl group (-OH)
2. Methyl group (-CH3)
3. Hydrogen atom (-H)
4. The carbon from the alpha carbon (which is different)

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

### Step 5: Count the Chiral Centers
Now that we have identified the chiral centers:
- The alpha carbon (1 chiral center)
- The carbon in the side chain (1 chiral center)

Thus, Threonine has a total of **2 chiral centers**.

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

---