Biochemistry Vitamins and Minerals Quiz

Biochemistry

• Biochemistry is the science concerned with the study of chemical reactions that occur in living organisms.

Vitamins

• Vitamins are organic nutrients required in small quantities for various biochemical functions and cannot be synthesized in the body.
• Vitamins assist in the formation of hormones, blood vessels, nervous system chemicals, and genetic materials.
• Vitamins act as catalysts, combining with proteins to create metabolically active enzymes essential for life reactions.

Classification of Vitamins

• Vitamins can be classified into water-soluble and fat-soluble vitamins.

Water-Soluble vs Fat-Soluble Vitamins

• Water-soluble vitamins:
  • Are soluble in water
  • Are absorbed simply
  • Are not stored in the body
  • Are excreted
  • Excess intake is non-toxic
  • Deficiency manifests rapidly
  • Treatment involves regular dietary supply
• Fat-soluble vitamins:
  • Are soluble in fat
  • Are absorbed along with lipids
  • Are stored in the liver
  • Are not excreted
  • Excess intake is toxic
  • Deficiency manifests slowly
  • Treatment involves a single large dose

Fat-Soluble Vitamins: Vitamin A

• Vitamin A occurs in two forms in food: retinoids and carotenoids.
• Retinoids are preformed vitamin A found only in foods of animal origin.
• Carotenoids are found in plants, comprise carotenes and related compounds, and are known as provitamin A.
• Vitamin A functions include:
  • Vision
  • Antioxidant activity
  • Regulation of gene expression and tissue differentiation
  • Essential for health and growth
  • Essential for bone formation and calcification
  • Gene regulation during early fetal development
• Vitamin A toxicity can occur with doses above 200 mg of retinol or retinal, or chronic consumption of more than 40 mg/day, causing symptoms such as gastrointestinal issues, neurological symptoms, dermatological symptoms, and musculoskeletal issues.
• Vitamin A deficiency can cause night blindness, xerophthalmia, infections, keratinization of skin, and impairment of immune responses.

Fat-Soluble Vitamins: Vitamin D

• Vitamin D is not strictly a vitamin since it can be synthesized in the skin, and under most conditions, that is its major source.
• Vitamin D is present in two forms: ergocalciferol (vitamin D2) found in plants and cholecalciferol (vitamin D3) found in animal tissues.
• Vitamin D is present in only a few natural foodstuffs, including liver, egg yolk, and saltwater fish.
• The main function of vitamin D is in the regulation of calcium absorption.
• Vitamin D is synthesized in the skin by the action of ultraviolet radiation, and then hydroxylated to 25-hydroxycholecalciferol in the liver and further hydroxylated to 1,25-dihydroxycholecalciferol (calcitriol) in the kidney.
• Vitamin D deficiency can cause rickets in children, osteomalacia in adults, and osteoporosis.
• Vitamin D toxicity, caused by overuse of supplements, leads to hypercalciuria and metastatic calcification (abnormal calcification of soft tissues).
• Symptoms of vitamin D toxicity include anorexia, weight loss, irregular heart beat, and hardening of blood vessels and tissues due to increased blood levels of calcium.

Fat-Soluble Vitamins: Vitamin E

• Vitamin E is the generic descriptor for two families of compounds: the tocopherols and the tocotrienols.
• The most active form is D-α-tocopherol.
• The main function of vitamin E is as a chain-breaking, free radical-trapping antioxidant in cell membranes and plasma lipoproteins.
• Vitamin E is an antioxidant and scavenger of free radicals, protecting membranes, fat depots, and lipoprotein from lipid peroxidation.

Test your knowledge of biochemistry, vitamins, and minerals. This quiz covers various aspects of biochemistry, including vitamins and minerals like Na, Mg, Fe, and Ca.