Question

Select the true statements.
The final structure of a protein with one polypeptide chain is its tertiary structure.
A tertiary structure has multiple polypeptide chains.
Secondary structures interact to form a tertiary structure.
A protein's tertiary structure is important for its function.

Answer 1

True statements: 1, 3, and 4.

Brief explanations:
- 1 is true: for a single polypeptide chain, the overall folded 3D structure is the tertiary structure.
- 2 is false: multiple polypeptide chains interacting form a quaternary structure, not tertiary.
- 3 is true: secondary elements (α-helices, β-sheets) pack and interact to make the tertiary fold.
- 4 is true: the specific tertiary fold is critical for a protein’s function.