Final answer:
Proteins have various roles in living organisms, including maintaining cell shape, muscle function, and transporting materials. They also act as signals, enzymes, and antibodies.
Step-by-step explanation:
Proteins play various roles in living organisms. They can help maintain cell shape (structural proteins), make up muscle tissues (connective and motor proteins), and transport materials in and out of cells (transport proteins). Proteins also act as signals and receptors, and play a key role in chemical reactions as enzymes. They can also be antibodies that bind and target foreign substances for destruction.
Examples:
- Structural proteins help maintain the shape of cells, such as collagen in connective tissues.
- Enzymes are proteins that speed up chemical reactions, like amylase breaking down starch into sugars.
- Hemoglobin, a protein in red blood cells, carries oxygen from the lungs to body cells.