Lipid Function 5

Question 1

Lipid Function

Answer 1

1. Conenzymes in electron transport chain & in
    glycosylation rxns
2. Intracellular messengers responding to extracellular 
    signals
3. Hormones
4. Light-absorbents [retina]
5. Pigments
6. Energy storage

Question 2

3 Categories of Signaling Lipids

Answer 2

1. Steroids
2. Prostaglandins
3. Fat-soluble Vitamins

& 4. Terpenes

Question 3

Terpenes/Terpenoids

Answer 3

Odiferous precursors of steroids composed of isoprene units (C5H8)

Types: Give rise to:
1. Monoterpenes———oil extracts
2. Sesquiterpenes
3. Diterpenes————-Vitamin A
4. Triterpenes————Cholesterol & Steroids
5. Tetraterpenes——–Carotenoids like B-carotin &
lutein

Question 4

Steroids

Answer 4

Identity
1. Category of signaling lipid driven from triterpenes Chemical Structure
1. 3cyclohexane fused to 1cyclopentane
2. Function depends on oxidation of these rings
and the functional groups that they carry
Function
1. Gives rise to Cholesterol

Question 5

Cholesterol

Answer 5

Identity-

An amphipathic steroid derivative that gives the phospholipid bilayer membrane of a cell its fluidity; keeping it from solidifying at low temperatures and from becoming too permeable at exceedingly high T

Derivatives-

1. Bile acid    2. Steroid hormones    3. Vitamin D

Question 6

Steroid Hormones

Answer 6

Cholesterol derivatives secreted by the endocrine system that bind to protein transporters until they reach a receptor that has high affinity for them through which they alter DNA expression in a cell.

Types:

1. Androgen
2. Testosterone
3. Progestrone
4. Estrogen
5. Cortisol
6. Aldosterone

Question 7

Prostaglandins

Answer 7

Identity:
1. One type of signaling lipid composed of
unsaturated 4 cycloalkanes and hydrocarbon
chains
Function:
1. serve as autocrine & paracrine signaling
molecules
2. Regulate the synthesis of cAMP which has an
effect in
A. elevation of body T as a result of pain &
fever
B. function of smooth muscles
C. regulation of the sleep-wake cycle

Question 8

Fat-Soluble Vitamins

Answer 8

Identity: 
      1. Third category of signaling lipids stored in fat
Types: 
      1. A
     2. D
     3. E
     4. K

Question 9

Vitamin A

Answer 9

AKA Carotene, is one type of fat-soluble vitamin composed of diterpenes that has significant roles in

     1. vision
    2. Growth/Development
    3. Immune functioning

Gives rise to retinol, light-absorbing component of retina

Question 10

Retinoic Acid

Answer 10

Oxidized form of retinol, Vitamin A storage in retina, that regulates gene expression during epithelial development

Question 11

Vitamin D

Answer 11

AKA cholecalciferol, is one type of fat-soluble vitamin that gets consumed in UV lights. After being converted to calcitriol, the active form of cholecalciferol, it can contribute to bone formation by increasing uptake of calcium and phosphate in the intestine.

**Vitamin D deficiency leads to rickets.

Question 12

Rickets

Answer 12

A developmental disorder resulting from deficiency of vitamin D in which long bones grow having a curved appearance

Question 13

Vitamin E

Answer 13

—-Characterizes 2 closely related lipids known as
tocopherols and tocotrienols that have antioxidant
properties, destroying free radicals that give rise to
cancer and aging with their aromatic structure.

Question 14

Vitamin K

Answer 14

• –Composed of K1 & K2
• —is essential to post-translational modification [oxidation and reduction] of prothrombin which is an important blood clotting factor

Question 15

Energy Storing Lipid Molecule

Answer 15

Triacylglycerol–

Effective Source of Energy Storage b/c:
1. is hydrophobic, does not require water; therefore
weighs less
2. Is more fully reduced relative to hydrocarbonds;
therefore yields twice as much energy upon
oxidation
3. Provides insulation in cold, decreasing need for
energy consumption

Question 16

TriAcylglycerol/Triglyceride

Answer 16

Identity
1. Nonpolar sources of energy storage stored in
animal adipocytes and plant seeds
2. Identity depends on level of fatty acid saturation

Chemistry:
1. Three fatty acids are bonded to a glycerol
backbone using ester bonds
2. Each of the component fatty acids differs in its
saturation level and length

Question 17

Adipocytes

Answer 17

Cells underneath the skin, in the abdomen and around the mammary glands that store fat.

Question 18

Free Fatty Acids

Answer 18

Unesterified fatty acids with a free carboxylic acid circulating in the blood stream binded to albumin serum

Question 19

Saponification

Answer 19

Process of soap production through ester hydrolysis of triacyglycerols using a strong base to cleave fatty acid salts and release them as soap

Question 20

lye

Answer 20

NaOH or KOH; based used to ester hydrolyze triacylglycerols in saponification

Question 21

Soap

Answer 21

Fatty acid salt cleaved from triacylglycerol using lye that dissolves both polar and nonpolar compounds by forming micelles that house nonpolar fattyacids inside and keep hydrophillic groups on the surface

—–Soaps are surfactants that reduce surface tension

Question 22

Micelles

Answer 22

Aggregates of polar and nonpolar compounds that help with emulsification of fat-soluble vitamins, bile-salts, and fatty acids.