Read the article “Hyaluronic acid: A key molecule in skin aging” and answer the guide questions below.

• Based on the article, what causes skin aging?
• What is the structure of HA made up of?
• HA is most abundant in what human body part?
• List the functions of HA in the body.
• What enzymes are involved in the synthesis of HA?
• What happens during HA degradation?
• How is HA degraded non-enzymatically?
• What is the significance of having high levels of HA in the dermis?
• What causes premature skin aging?
• Note what observations were made about intrinsic skin aging? What is the result of this inevitable physiological process?