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, we will analyze each option one by one.

### Step-by-Step Solution:

1. **Statement 1: A protein is a heteropolymer and not a homopolymer.**
- **Analysis:** Proteins are made up of different types of amino acids, which means they are composed of various monomer units. Therefore, this statement is true.

2. **Statement 2: Collagen is the most abundant protein in the animal world.**
- **Analysis:** Collagen is indeed the most abundant protein found in animals, making up a significant part of connective tissues. Thus, this statement is also true.

3. **Statement 3: Rubisco is the most abundant protein in the whole biosphere.**
- **Analysis:** Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is known to be the most abundant protein on Earth, as it plays a crucial role in the Calvin cycle of photosynthesis. Therefore, this statement is true as well.

4. **Statement 4: The first amino acid in a polypeptide chain is called the C-terminal amino acid, and the last amino acid is an N-terminal amino acid.**
- **Analysis:** This statement is false. 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. Thus, this statement is incorrect.

### Conclusion:
The false statement regarding proteins is **Statement 4**.

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