Question

Discuss the main functions of proteins in living systems.

Short answer

Proteins in living systems carry out various functions including metabolic reactions, structural support, substance transport, body defense, regulation of cell growth and differentiation, and facilitating movement.

Step-by-step solution

Defining Proteins

Proteins are critical components of all living organisms and perform a diverse range of functions. They are biological macromolecules made up of one or more chains of amino acids.

Discussing Metabolic Function

Proteins play a vital role in metabolism. Metabolic enzymes, which are proteins, speed up biochemical reactions in cells.

Discussing Support Function

Some proteins provide structural support to cells and organisms. For example, collagen and keratin are structural proteins that help form connective tissues, skin, hair, and nails.

Discussing Transport Function

Proteins also transport substances within and between cells. Hemoglobin is a protein that transports oxygen in the blood.

Discussing Defense Function

Proteins can defend the body against foreign substances. Antibodies are proteins that specifically recognize and bind to foreign substances or antigens, thereby neutralizing them or marking them for destruction.

Discussing Regulatory Function

Certain proteins, such as hormones and receptors, play a role in cellular regulation. They can control cell growth, differentiation, and gene expression to maintain cell and body homeostasis.

Discussing Motion Function

Proteins like actin and myosin contribute to cellular movements and muscle contraction, thereby enabling organismal movement.