Representative Lipids Found in the Body

Question 1

Triglycerides (neutral fats)

Answer 1

• Found in fat deposits (subcutaneous tissue and around organs)
• Protect and insulate the body organs
• The major source of stored energy in the body

Question 2

Phospholipids

Answer 2

• Found in cell membranes
• Participate in the transport of lipids in plasma
• Abundant in the brain and the nervous tissue in general, where they help to form insulating white matter

Question 3

Cholesterol (Steroids)

Answer 3

The basis of all body steroids

Question 4

Bile salts (Steroids)

Answer 4

• A breakdown product of cholesterol

* Released by the liver into the digestive tract, where they aid in fat digestion and absorption

Question 5

Vitamin D (Steroids)

Answer 5

• A fat-soluble vitamin produced in the skin on exposure to U V (ultraviolet) radiation (sunshine)
• Necessary for normal bone growth and function

Question 6

Sex hormones (Steroids)

Answer 6

• Estrogen and progesterone (female hormones) and testosterone (a male hormone) produced from cholesterol
• Necessary for normal reproductive function
• Deficits result in sterility

Question 7

Corticosteroids (adrenal cortical hormones) (Steroids)

Answer 7

• Cortisol, a glucocorticoid, is a long-term anti-stress hormone that is necessary for life
• Aldosterone helps regulate salt and water balance in body fluids by targeting the kidneys

Question 8

Vitamin A (Fat-soluble vitamins)

Answer 8

• Found in orange-pigmented vegetables (carrots) and fruits (tomatoes)
• Part of the photoreceptor pigment involved in vision

Question 9

Vitamin E (Fat-soluble vitamins)

Answer 9

• Taken in via plant products such as wheat germ and green leafy vegetables
• May promote wound healing and contribute to fertility, but not proven in humans
• An antioxidant
• May help to neutralize free radicals (highly reactive particles believed to be involved in triggering some types of cancers)

Question 10

Vitamin K (Fat-soluble vitamins)

Answer 10

• Made available largely by the action of intestinal bacteria
• Also prevalent in a wide variety of foods
• Necessary for proper clotting of blood

Question 11

Prostaglandins (Fat-soluble vitamins)

Answer 11

• Derivatives of fatty acids found in cell membranes
• Various functions depending on the specific class, including stimulation of uterine contractions (thus inducing labor and miscarriages), regulation of blood pressure, and control of motility of the gastrointestinal tract
• Involved in inflammation

Question 12

Lipoproteins (Fat-soluble vitamins)

Answer 12

• Lipoid and protein-based substances that transport fatty acids and cholesterol in the bloodstream
• Major varieties are high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs)

Question 13

Glycolipids (Fat-soluble vitamins)

Answer 13

• Component of cell membranes
• Lipids associated with carbohydrate molecules that determine blood type, play a role in cell recognition or in recognition of foreign substances by immune cells