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Flashcards in Lipid Function 5 Deck (22):
1

Lipid Function

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

2

3 Categories of Signaling Lipids

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

& 4. Terpenes

3

Terpenes/Terpenoids

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

4

Steroids

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

5

Cholesterol

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

6

Steroid Hormones

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

7

Prostaglandins

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

8

Fat-Soluble Vitamins

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

9

Vitamin A

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

10

Retinoic Acid

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

11

Vitamin D

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.

12

Rickets

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

13

Vitamin E

----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.

14

Vitamin K

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

15

Energy Storing Lipid Molecule

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

16

TriAcylglycerol/Triglyceride

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

17

Adipocytes

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

18

Free Fatty Acids

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

19

Saponification

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

20

lye

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

21

Soap

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

22

Micelles

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