Lipids Flashcards
lipid definition
group of water-insoluble (hydrophobic) organic molecules
lipid function
major energy source for the body, stored as triacylglycerol (triglycerides)
classifications of lipids
FA’s, triglycerides, glycerophospholipids, sterols, sphingolipids, and eicosanoids
fatty acids
used as stored energy in living organisms, are carboxylic acids w/ hydrocarbon chains
nonesterified vs esterified FA’s
nonesterified: exist freely in the body
esterified: within complex molecules, like triglycerides
saturated vs unsaturated FA’s
saturated: contain no carbon-carbon double bonds
unsaturated: contain carbon-carbon double bonds (mono-: 1 double bond, poly-: mult. double bond)
FA nomenclature
carboxyl group carbon labeled as #1
- chain length: # of double bonds (location)
- delta sign used for double bonds
FA’s characteristics
chain length: longer chains = more hydrophobic and higher melting point
degree of unsaturation: more double bonds = lower melting point, greater degree of fluidity
what is more common in FA, double bonds in cis or trans config?
cis configuration
omega-3 FA’s
double bond between third and fourth carbon from the end of the chain (omega end)
- good for the eye
triglycerides types
simple TAG: 3 of the same kind of FA
mixed TAG: more common- varying chain length/saturation
triglyceride general info
mostly found in adipocytes, mainly broken down to form acetyl-coA
FA as an energy source
yields more than 2x the energy of carbs, may sustain an individual when dietary intake is low
phospholipids definition
lipid class for the formation and maintenance of all forms of cell membranes
-either glycero- or sphingolipids
structure of phospholipids
- is amphipathic (both hydrophobic and hydrophilic properties)
- polar head group: face intra/extracellularly
- non polar tail: buried within the cell membrane
phosphoglycerides definition
main component of biological membranes, glycerol-based phospholipid
- polar head group: phosphate group + alcohol
- non-polar FA tail
sphingolipids
polar head group and two nonpolar tails w/ no glycerol component
-consist of amino alcohol sphingosine
sterols definition
steroids w/ 8-10 C’s in the side chain of carbon 17 and a (-OH) group at carbon 3
major sterol in tissue
cholesterol
sterol function
component of plasma membrane, precursor for synthesis of steroid hormones
what’s the precursor for steroid hormones
cholesterol is the precursor of all steroid hormones
steroid hormones function
trigger changes in gene expression and metabolism, by traveling through bloodstream from site of synthesis to target organ
vitamin general info
- either water soluble or vitamin soluble
- must be obtained through diet
-required in constant, small amounts because it’s readily eliminated through the urine
Vitamin B1 (thiamine)
-coenzyme important for pentose-phosphate rxn and several dehydrogenase complexes
vitamin B1 deficiencies
fatal condition, can lead to heart failure
- beriberi: typical B1 def syndrome
-wernicke-korsakoff: neuro disturbance, assoc w/ alcoholism
encephalopathy: ataxia, confusion, EOM paralysis
korsakoff’s psychosis: amnesia
vitamin B2: riboflavin
precursor of flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD)
vitamin B2 deficiency
dermatitis, assoc. w/ other B complex deficiencies
vitamin B3: niacin
- active coenzymes forms are NADH and NADPH
vitamin B3 deficiency
pellagra (skin, GI tract, CNS)
vitamin B9: folic acid
-coenzyme essential for synthesis of certain AA’s and nucleotides
vitamin B9 deficiencies
most common vitamin deficiency in US, common in pregnant women, and alcoholism
- megaloblastic anemia and spina bifida
vitamin B12: cobalamin
key role in DNA synthesis and RBC formation, obtained from meat
vitamin B12 deficiency
-most common worldwide
- causes both neurological and hematological abnormalities
- pernicious anemia
- sensory neuropathy
vitamin C: ascorbic acid
-helps form and repair CT
- acts as an antioxidant
- important for aqueous and vitreous humor
vitamin C deficiency
scurvy
Water vs fat soluble vitamins
fat soluble: vitamin C, and B complex
water soluble: ADEK
vitamin D
- mainly from sunlight
- inactive vit D is converted to calcitriol (active Vit D)
- regulates Ca2+ intake in the intestine, and Ca2+ levels in kidney/bones
vitamin D deficiency & toxicity
deficiency: rickets in children, osteomalacia in adults
toxicity: hypercalcemia, band keratopathy
vitamin A
- 2 types:
1. retinoids- important for vision transduction
2. carotenoids: green leafy veggies
vitamin A deficiency
dry eyes/skin, stunted growth
vitamin K
- coenzyme involved in blood clotting cascade
- bacteria produces half, other half form plants
vitamin K deficiency
excessive bleeding, lack of clotting
vitamin E
- antioxidants for membrane of proteins and lipids
- reduces the effects of aging
- part or AREDS treatment for mac degen
minerals
chemical elements needed for normal structure and function of the body
- 2 types: macrominerals (ex calcium, sodium, etc.)
trace elements (ex iron, copper, etc.)
eicosanoids
3 classes: prostaglandins, thromboxanes, leukotrienes
- short acting, local hormones
micelle
lipid bilayer, looks like a donut
liposomes
solvent filled vesicle, looks like donut hole
transverse diffusion
is rare because it would have to go across the lipid bilayer
lateral diffusion
fast process and highly mobile in this plane
