Chapter 5.3

Question 1

Why use fatty acids for energy storage instead of sugars. Give two reasons

Answer 1

• the carbon atoms of fatty acids are more reduced than those of sugars
• > sugars contain more alcohol groups
• therefore, the oxidation of triacylglycerols yield twice the amount of energy per gram of carbohydrates
• note triacylglycerols are hydrophobic
• > they do not require hydrogen for stability
• > this helps decrease their weight
• layer of lipids serve as insulation
• > maintain a constant internal temperature

Question 2

Describe the general structure of triacylglycerols

Answer 2

• they are also called triglycerides
• three fatty acid backbones
• > ester linked to glycerol

-these compounds are nonpolar and hydrophobic

Question 3

What cells store triacylglycerols

Answer 3

• adipocytes store large amounts of fat or triacylglycerols

- they are found primarily under the skin, around mammary glands and the abdominal cavity

Question 4

What are free fatty acids? How do they exist within our body(what is their method of transportation)

Answer 4

• unesterified fatty acids with a free carboxylate group

- in the body they circulate in the blood bonded noncovalently to serum albumin

Question 5

Describe the general mechanism of saponification

Answer 5

• it is the ester hydrolysis of triacylglycerols
• > using a strong base(lye) using sodium hdroxide
• > the result is the sodium salt of the fatty acid (soap) and glycerol

Question 6

What is the relationship between soap and surfactant

Answer 6

• soap can act as a surfactant
• > it lowers the surface tension at the surface of a liquid
• > serving as a detergent or emulsifier

Question 7

Can soap form micelles

Answer 7

• yes it can

- >hydrophobic tails tuned inward of phospholipids and hydrophilic heads turned outward