Starting with three different amino acid molecules, how many different tripeptide molecules are formed

Options

A. 12
B. 9
C. 8
D. 6

Explanation

To determine how many different tripeptide molecules can be formed from three different amino acid molecules, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Tripeptides**: A tripeptide is formed by linking three amino acids together through peptide bonds. Each amino acid contributes to the overall structure of the tripeptide.

2. **Identifying the Amino Acids**: Let's denote the three different amino acids as A, B, and C.

3. **Arranging the Amino Acids**: The first step in forming a tripeptide is to arrange the three amino acids in different sequences. Since the order matters in tripeptides, we need to calculate the permutations of the three amino acids.

4. **Calculating Permutations**: The number of ways to arrange n different items is given by n!. For our case, we have 3 amino acids:
\[ \text{Number of arrangements} = 3! = 3 \times 2 \times 1 = 6 \]

5. **Conclusion**: Therefore, starting with three different amino acid molecules, we can form 6 different tripeptide molecules.

### Final Answer:
The total number of different tripeptide molecules that can be formed from three different amino acids is **6**.

---