Which of the following statements is false regarding proteins ?

Options

A. A protein is heteropolymer and not a homopolymer
B. Collagen is the most abundant protein in the animal world
C. RuBisCO is the most abundant protein in the whole biosphere
D. The first amino acid in the polypeptide chain is called as C-terminal amino acid and the last amino acid is called as N-terminal amino acid.

Answer

To determine which statement is false regarding proteins, let's analyze each statement step by step:

### Step 1: Analyze the first statement
**Statement:** "Protein is a heteropolymer and not a homopolymer."
**Explanation:** Proteins are indeed considered heteropolymers because they are made up of different types of amino acids. In contrast, homopolymers consist of only one type of monomer. Therefore, this statement is **true**.

### Step 2: Analyze the second statement
**Statement:** "Collagen is the most abundant protein in the animal world."
**Explanation:** Collagen is a structural protein found in connective tissues and is known to be the most abundant protein in animals. This statement is also **true**.

### Step 3: Analyze the third statement
**Statement:** "Rubisco is the most abundant protein in the whole biosphere."
**Explanation:** Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is indeed a crucial enzyme involved in the process of photosynthesis and is considered one of the most abundant proteins on Earth. This statement is **true**.

### Step 4: Analyze the fourth statement
**Statement:** "The first amino acid in the polypeptide chain is called the C-terminal amino acid and the last amino acid is called the N-terminal amino acid."
**Explanation:** This statement is incorrect. The first amino acid in a polypeptide chain is referred to as the N-terminal amino acid, while the last amino acid is called the C-terminal amino acid. Therefore, this statement is **false**.

### Conclusion
The false statement regarding proteins is: **"The first amino acid in the polypeptide chain is called the C-terminal amino acid and the last amino acid is called the N-terminal amino acid."**

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