Molecular weight of smallest proteins molecule ACTH(adrenocorticotropic hormone) is

Options

A. 5600
B. 4500
C. 3100
D. 6200

Answer

To determine the molecular weight of the smallest protein molecule ACTH (adrenocorticotropic hormone), we can follow these steps:

### Step 1: Understand the Composition of ACTH
ACTH is a polypeptide hormone composed of amino acids. Specifically, it is made up of 39 amino acids.

**Hint:** Remember that proteins are polymers of amino acids, and the molecular weight can be calculated based on the number of amino acids.

### Step 2: Calculate the Average Molecular Weight of an Amino Acid
The average molecular weight of an amino acid is approximately 110 Daltons. This is a rough estimate, as the actual weight can vary slightly depending on the specific amino acids involved.

**Hint:** Use the average molecular weight of amino acids to estimate the total weight of the protein.

### Step 3: Calculate the Total Molecular Weight of ACTH
To find the total molecular weight of ACTH, multiply the number of amino acids by the average molecular weight of an amino acid:
\[ \text{Total Molecular Weight} = \text{Number of Amino Acids} \times \text{Average Molecular Weight of an Amino Acid} \]
\[ \text{Total Molecular Weight} = 39 \times 110 \approx 4290 \text{ Daltons} \]

**Hint:** Multiply the number of amino acids by the average weight to get a rough estimate of the protein's molecular weight.

### Step 4: Compare with Given Options
The calculated molecular weight of ACTH is approximately 4290 Daltons. However, the options provided are 5600, 4500, 3100, and 6200 Daltons. The closest value to our calculation is 4500 Daltons.

**Hint:** Always compare your calculated value with the provided options to select the best match.

### Step 5: Conclusion
The molecular weight of the smallest protein molecule ACTH is approximately 4500 Daltons, which is the nearest option provided.

**Final Answer:** 4500 Daltons.