Final answer:
Proteins serve a variety of essential functions within cells, including providing structural support, acting as enzymes, transporting substances like oxygen, functioning as antibodies, and carrying messages as hormones. Their functions are determined by their amino acid structures, and changes to these structures can severely impact their function.
Step-by-step explanation:
Proteins have many different functions in a cell, which include but are not limited to the following:
Structural support to help cells maintain their shape, as seen with structural proteins and connective tissues in muscles.
Functioning as enzymes to speed up chemical reactions in cells, such as digestion.
Serving as transport proteins, like hemoglobin, which binds with oxygen and transports it throughout the body.
Acting as antibodies that recognize and help destroy foreign substances like bacteria.
Carrying messages as regulatory molecules and hormones to help regulate body functions.
Each protein's function is highly dependent on its structure, which is a complex arrangement of amino acids. A change in the structure of a protein, such as those caused by mutations, can lead to a loss of function or diseases. Proteins are vital for virtually every aspect of a cell's structure and function.