Final answer:
Collagen, lipase, and hemoglobin are all proteins that share the common characteristics of being polymers of amino acids and having biological functions, irrespective of their physical properties like solubility or roles such as enzymatic activity.
Step-by-step explanation:
Collagen, lipase, and hemoglobin, despite their diverse roles, share common characteristics that qualify them as proteins. These characteristics are that they are polymers of amino acids and have biological functions. Collagen provides structural support in connective tissues, lipase helps in breaking down lipids into fatty acids and glycerol, and hemoglobin is crucial for oxygen transport in the blood. All proteins, irrespective of their shape or function, are formed by the combination of amino acids in specific sequences. These sequences determine the protein's unique structure and role within biological systems.
Proteins can be broadly grouped into fibrous or globular categories. Fibrous proteins like collagen tend to be water-insoluble and provide structural functions, whereas globular proteins such as hemoglobin are water-soluble and serve a variety of functions, including acting as enzymes or transport molecules. Proteins are essential to life's processes and despite varying solubility or enzymatic activity, their foundation as amino acid polymers and their integral biological roles bind them to a common classification.