What roles do proteins play in organisms?

They play huge role in organisms, every living organism needs proteins.

- enzymatic role (they build enzymes which lower an activation energy in reactions and increase reaction speed)

- hormonal role (they build hormons)

- structural role (for example keratin)

- transport role (for example hemoglobin)

- energetic role (for example aleurone grains in plant cells or they are used to gain energy in human organism when it's out of lipids and carbohydrates)