Chap 23

Question 1

Waxes

Answer 1

• An ester formed between two fatty acids. Secreted from sebaceous glands for protection, bees make it

Question 2

fatty acid-saturated vs unsaturated

Answer 2

• Carboxyl group with long carbon backbone attached. Saturated has no double bonds, while unsaturated has double bonds.

Question 3

Saturated and unsaturated fats to know

Answer 3

• Saturated
  o Palmitic acid – 16C – CH3(CH2)14COOH
  o Stearic acid – 18C – CH3(CH2)16COOH
• Unsaturated
  o Oleic – 18C – 1 double bond at carbon 9 (omega 9)
  o Linoleic – 18C – 2 double bonds, one at 9 and one at 12 (omega 6)
  o Linolenic – 18C – 3 double bonds, one at 9, 12, and 15 (omega 3)

Question 4

an “omega-3, or omega 6

Answer 4

• Has the first double bond 3, 6, or 9 carbons from the omega carbon (last C)

Question 5

What is the difference between a fat and an oil?

Answer 5

• Fats – solid triglycerides – contain high proportion of saturated fats.
• Oils – liquid triglycerides – contain high proportion of unsaturated fats.

Question 6

Are most double bonds in unsaturated fatty acids found in animals cis, or trans?

Answer 6

• cis

Question 7

hydrogenation and what effect this has on lipids.

Answer 7

• Adding H atoms to an unsaturated fatty acid. This can result in trans fats.

Question 8

Where do most trans fatty acids come from in our diets? What physical properties do trans fatty acids have in common with saturated fats?

Answer 8

• Processed foods. They are straight, like saturated fats so they stack well but don’t get broken down easily.

Question 9

When you hydrolyze oils or fats with a base, what happens? What is this called?

Answer 9

• Soaps are formed. Saponification

Question 10

Know how soaps and detergents work.

Answer 10

• They have a hydrophilic end and a hydrophobic end. The hydrophobic end reacts with fats, then gets dissolved in water in micelles.

Question 11

lipids in cellmemembrane

Answer 11

• Glycerophopholipid – amino alcohol - phosphate - glycerol - 2 fatty acid chains
  o Very abundant in most cell membranes
• Sphingomyelin – amino alcohol – phosphate – sphingosine – 1 fatty acid (via amide)
  o Along the spinal cord
• Glycolipic – sugar – sphingosine – 1 fatty acid (via amide)
  o In the brain

Question 12

cholesterole and steroidsturcture

Answer 12

• Cholesterol makes up about 1/3 of cell membranes. Provides rigidity.
• Steroids have 3 6 fused 6 carbon rings as well as a 5 carbon ring.

Question 13

What is the major function of cholesterole

Answer 13

• Provide rigidity to cell membranes

Question 14

fluid-mosaic model

Answer 14

integral, and peripheral membrane proteins

• Integral goes into the hydrophobic portion of membrane
• Peripheral just interacts with the lipid heads.

Question 15

different types of transport across membranes

Answer 15

o Simple occurs because of osmosis. Only nonpolar molecules
o Facilitated occurs through a protein channel, without energy
Active – runs against a gradient and required energy

Question 16

three major types of eicosanoids

Answer 16

leukotrienes: three conjugated double bonds
- Cause inflammation, trigger asthmatic response and allergic reactions
Prostaglandins: cyclopentane ring
- Stimulate uterine contractions, induce labor and cause inflammation
- Targeted by aspirin, blocks the formation from arachidonic acid
thromboxanes: six-membered cyclic ether- ring