Lipids

Question 1

Lipids

Answer 1

Oily or fat substances

Question 2

Three primary physiological roles of lipids

Answer 2

• In adipose cells, triglycerides store energy
• In cellular membranes, phospholipids constitute a barrier between intracellular and extracellular environments
• Cholesterol is a special lipid that serves as a building block for the hydrophobic steroid hormones

Question 3

Fatty acids

Answer 3

Long unsubstituted alkanes that end in a carboxylic acid
No carbon-carbon double bond = saturated
One or more double bonds = unsaturated

Question 4

Triacyglycerols

Answer 4

Storage form of fatty acids

Composed of three fatty acids esterified to a glycerol molecule

Question 5

Saponification

Answer 5

Base-catalyzed hydrolysis of triglycerides from animal fat into fatty acid salts (soap)

Question 6

Lipases

Answer 6

Enzymes that hydrolyze fats

Question 7

Structural determinants of membrane fluidity

Answer 7

Degree of saturation, tail length, and amount of cholesterol

Question 8

Squalene

Answer 8

Biosynthetically utilized in the manufacture of steroids

Question 9

Sphingolipids

Answer 9

Structured in a similar manner as phospholipids, except that the backbone is sphingosine instead of glycerol
Sphingomyelin - an important component of the myelin sheath around neurons

Question 10

Waxes

Answer 10

Long chain fats esterified to long chain alcohols

Question 11

Fat-soluble vitamins

Answer 11

Absorbed with dietary fat and stored in adipose tissue and in the liver
Four fat-soluble vitamins - Vitamins, A,D,E,K

Question 12

Vitamin A

Answer 12

Terpenoid

Essential for vision, growth, epithelial maintenance, and immune function

Question 13

Vitamin D

Answer 13

Derived from cholesterol

Important in regulating blood levels of calcium and phosphate

Question 14

Vitamin E

Answer 14

Group of compounds called tocopherols

Important as antioxidants

Question 15

Vitamin K

Answer 15

Serves as an important coenzyme in the activation of clotting proteins

Question 16

Prostaglandins

Answer 16

Belong to a group of molecules known as eicosanoids
Roles include: regulating smooth muscle contraction in the intestines and uterus, regulating blood vessel diameter, maintaining gastric integrity (by decreasing acid secretion and increasing mucus secretion)

Question 17

Ketone bodies

Answer 17

Generated from acetyl-CoA and include acetone, acetoacetate, and beta-hydroxybutyrate
Can cross the blood brain barrier and be converted back to acetyl-CoA once they arrive at their target organ
Tend to be acidic