Biochemistry Chapter 5: Lipid Structure and Function Flashcards
Are lipids soluble in water? nonpolar organic solvents?
Water - no
Nonpolar organic solvents - yes
What does it mean to be amphipathic?
Both polar and nonpolar
What are lipids composed of?
hydrophilic (polar) head group and a nonpolar hydrophobic tail
How is the head group attached?
Via a phosphodiester linkage
What determines the fluidity of the membrane?
saturation – saturated are less fluid than unsaturated.
What are sphingolipids?
contain a sphingosine backbone – many are also phospholipids - called sphingophospholipids.
What are sphingomyelins?
Major class of sphingolipids and contain a phosphatidycholine or phosphatidylethanolamine head group – main component of the myelin sheath.
What are glycosphingolipids?
Attached to sugar moieties instead of a phosphate group. Cerebrosides have one sugar connected to sphingosine.
What is a cerebrosides?
have one sugar connected to sphingosine
What are globosides?
Have two or more sugars connected to sphingosine
What are gangliosides?
contain oligosaccharides with at least one terminal N-acetylneuraminic acid (NANA); also called sialic acid
What are waxes?
contain long-chain fatty acids esterified to long-chain alcohols. They are used as protection against evaporation and parasites in plants and animals.
What are terpenes?
Odiferous steroid precursors made from isoprene; a 5-C molecule. 1 terpene unit = 2 isoprene units)
What are terpenoids?
derived from terpenes via oxygenation or backbone rearrangement.
Steroids
Contain 3 cyclohexane rings and one cyclopentane ring. Their oxidation state and functional groups may vary.
What are steroid hormone characteristics?
- high-affinity receptors
- work at low concentrations
- affect gene expression and metabolism
What is cholesterol?
important to membrane stability and fluidity; serves as a precursor to a host of other molecules.
What are prostaglandins?
autocrine and paracrine hormones that regulate cAMP levels. They have powerful effects on muscle contraction, body temperature and sleep-wake cycle and pain.
What are fat-soluble vitamins?
A, D, E, K
What is vitamin A for?
aka carotene
metabolized to retinal for vision and retinoic acid for gene expression in epithelial development
What is vitamin D for?
aka cholecalciferol
metabolized to calcitriol in the kidneys and regulates calcium and phosphorus homeostasis in the intestines (increasing calcium and phosphate absorption) promoting bone formation.
What is vitamin E for?
aka tocopherols
acts as biological antioxidants – their aromatic rings destroy free radicals, preventing oxidative damage.
What is vitamin K for?
aka phylloquinone and menaquinones
helps with formation of prothombin, a clotting factor. It performs posttranslational modifications on a number of proteins
What are triacylglycerides?
Preferred method of storing energy for long term use. They contain one glycerol attached to three fatty acids by ester bonds.
