Lipid Function 5 Flashcards
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 storage3 Categories of Signaling Lipids
- Steroids
- Prostaglandins
- Fat-soluble Vitamins
& 4. Terpenes
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
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
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
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:
- Androgen
- Testosterone
- Progestrone
- Estrogen
- Cortisol
- Aldosterone
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
Fat-Soluble Vitamins
Identity:
1. Third category of signaling lipids stored in fat
Types:
1. A
2. D
3. E
4. KVitamin 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
Retinoic Acid
Oxidized form of retinol, Vitamin A storage in retina, that regulates gene expression during epithelial development
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.
Rickets
A developmental disorder resulting from deficiency of vitamin D in which long bones grow having a curved appearance
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.
Vitamin K
- –Composed of K1 & K2
- —is essential to post-translational modification [oxidation and reduction] of prothrombin which is an important blood clotting factor
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
