Select the incorrect statement .

Options

A. 'Hb' is an example of quaternary structure of protein
B. In the primary structure of protein , the left hand is C - terminal and the right hand is N-terminal.
C. In protein or polypeptide , the amino acids are linked by peptide bond.
D. Most of the enzyme are Protein in nature.

Answer

To solve the question "Select the incorrect statement," we need to analyze the statements provided about protein structure and determine which one is incorrect. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Protein Structure
Proteins have four levels of structure:
1. **Primary Structure**: The sequence of amino acids in a polypeptide chain.
2. **Secondary Structure**: The folding of the polypeptide chain into structures like alpha-helices and beta-sheets.
3. **Tertiary Structure**: The overall three-dimensional shape of a single polypeptide chain.
4. **Quaternary Structure**: The arrangement of multiple polypeptide chains (subunits) in a protein.

### Step 2: Evaluate Each Statement
1. **Statement 1**: "Hemoglobin is an example of quaternary structure of protein."
- This statement is **true**. Hemoglobin consists of four subunits, making it a classic example of quaternary structure.

2. **Statement 2**: "In the primary structure of protein, left hand is C-terminal."
- This statement is **incorrect**. In the primary structure, the left end of the polypeptide chain is the N-terminal, while the right end is the C-terminal.

3. **Statement 3**: "In protein or polypeptide, amino acids are linked by peptide bonds."
- This statement is **true**. Amino acids are indeed linked by peptide bonds formed through dehydration reactions.

4. **Statement 4**: "Most enzymes are protein in nature."
- This statement is **true**. Most enzymes are proteins, with the exception of ribozymes, which are RNA molecules that can also catalyze reactions.

### Step 3: Identify the Incorrect Statement
From the evaluation, we find that:
- Statement 2 is the only incorrect statement regarding the structure of proteins.

### Conclusion
The incorrect statement is: **"In the primary structure of protein, left hand is C-terminal."**

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