Globular Proteins' Structural and Functional Traits

Steps:

• Recall globular proteins are compact, spherical, water-soluble molecules often functioning as enzymes or transporters.
• Assess option A: Globular proteins occur intracellularly and extracellularly, not exclusively in membranes.
• Assess option B: Globular proteins feature hydrophobic cores and hydrophilic surfaces for solubility.
• Identify correct option: Option C aligns with ATP-driven conformational changes in functions like enzyme activity.

Why C is correct:

• Globular proteins undergo ATP-powered shape changes, as in active transport (e.g., sodium-potassium pump) where ATP hydrolysis induces conformational shifts per the induced fit model.

Why the others are wrong:

• A: Many globular proteins, like hemoglobin, are soluble in cytoplasm, not limited to membranes.
• B: They include hydrophobic amino acids internally for stability, not only hydrophilic ones.
• D: Most globular proteins, such as myoglobin, are monomeric with primary or tertiary structure only.

Final answer: C