Answer to Question 1
The Functions of Body Proteins
1 . Growth and Maintenance
Proteins provide building materialsamino acidsfor growth and repair of body tissues.
Body structures. Proteins form vital parts of most body structures, such as skin, nails, hair, membranes, muscles, teeth, bones, organs, ligaments, and tendons.
2 . Regulatory Roles
Enzymes. Proteins facilitate numerous chemical reactions in the body; all enzymes are proteins.
Hormones. Some proteins act as chemical messengers, regulating body processes; not all hormones are proteins. Examples include: insulin, glucagon, and thyroid hormone.
Antibodies. Proteins assist the body in maintaining its resistance to disease by acting against foreign disease-causing substances.
Fluid balance. Proteins help regulate the quantity of fluids in body compartments.
Acidbase balance. Proteins act as buffers to maintain the normal acid and base concentrations in body fluids.
Transportation. Proteins move needed nutrients (e.g., minerals, lipids) and other substances (e.g., oxygen) into and out of cells and around the body.
3 . Energy and Glucose Production
Energy. Protein can be used to provide calories (4 calories per gram) to help meet the body's energy needs.
Answer to Question 2
True