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Module 11 in the Syllabus

Lipids Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for Lipids
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Conceptual Vocabulary
LipidLipids can be broadly defined as any fat-soluble (hydrophobic), naturally-occurring molecules.
Fatty acidA fatty acid is a carboxylic acid often with a long unbranched aliphatic tail, which is either saturated or unsaturated
FatsA wide group of molecules, fats are generally triesters of glycerol and fatty acids.
TriglycerideA triglyceride consists of glycerol esterified with three fatty acids, although slightly more formally, the form is known as triacylglycerol or triacylglyceride.
Saturated fatA saturated fat is a fat that consists of triglycerides containing fatty acids with no double bonds between the carbon atoms of the fatty acid chain
PhospholipidPhospholipids are a class of lipids which are a major component of all biological membranes, along with glycolipids, cholesterol and proteins.
Monounsaturated fatMonounsaturated fats are fatty acids having a single double bond present in the fatty acid chain, with all of the carbons in the chain single bonded
Polyunsaturated fatPolyunsaturated fats are fatty acids having more than one double bond present in the fatty acid chain.
DiglycerideA diglyceride, more formally known as a diacylglycerol, is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages.
SteroidA steroid is a terpenoid lipid characterized by a carbon skeleton with four fused rings generally arranged in a 6-6-6-5 fashion.
CholesterolCholesterol is a sterol found in the cell membranes of all physiological tissues and transported in the blood plasma of all animals.
GlycerophospholipidGlycerophospholipids or phosphoglycerides are glycerol-based phospholipids. They are the main component of biological membranes.
PhosphatidylcholinePhosphatidylcholine is a phospholipid which is a major constituent of cell membranes. This lipid is such a major component of lecithin that in some contexts the terms are used as synonyms.
TerpeneIncluding the essential oils of many plants, terpenes are a large and varied class of hydrocarbons which are derived biosynthetically from units of isoprene.
LecithinLecithin is mostly a mixture of glycolipids, triglycerides, and phospholipids. However, in biochemistry, the term is usually used as a synonym for pure phosphatidylcholine.
IsopreneIsoprene is a common synonym for the chemical compound 2-methylbuta-1,3-diene. It is an important biological material, being a precursor for many important classes such as the terpenes and steroids.
SqualeneSqualene is the triterpene which is the biochemical precursor to the whole family of steroids
ProstaglandinA prostaglandin is any member of a group of lipid compounds having 20 carbon atoms, including a 5-carbon ring which are derived enzymatically from fatty acids, having important functions in the animal body especially in immunity.
SterolSterols, or steroid alcohols are a subgroup of steroids with a hydroxyl group in the 3-position of the A-ring.
Omega-3 fatty acidOmega-3 fatty acids are a family of polyunsaturated fatty acids which have in common a double bond in the third carbon-carbon bond from the terminal end.
Omega-6 fatty acidOmega-6 fatty acids are a family of polyunsaturated fatty acids which have in common a double bond in the sixth carbon-carbon bond from the terminal end.
Omega-9 fatty acidOmega-9 fatty acids are a family of polyunsaturated fatty acids which have in common a double bond in the ninth carbon-carbon bond from the terminal end.
InositolInositol is a carbocyclic polyol that plays an important role as the structural basis for a number of secondary messengers in eukaryotic cells.
SphingolipidSphingolipids are a class of lipids derived from the aliphatic amino alcohol sphingosine.
TerpenoidThe terpenoids, sometimes referred to as isoprenoids, are a large and diverse class of naturally occurring organic chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways.
EicosanoidEicosanoids are signaling molecules derived from omega-3 or omega-6 fats. They exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system.
SphingomyelinSphingomyelin is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath which surrounds some nerve cell axons.
MonoterpeneMonoterpenes are a class of terpenes that consist of two isoprene units.
Advanced terms that may appear in context in MCAT passages
CaroteneThe terpene carotene is an orange photosynthetic pigment important for photosynthesis. It is responsible for the orange colour of the carrot and many other fruits and vegetables.
ProstanoidProstanoid is the term used to describe a subclass of eicosanoids consisting of the prostaglandins, the thromboxanes and the prostacyclins.
PhosphatidylserinePhosphatidylserine is a phospholipid nutrient found in fish, green leafy vegetables, soybeans and rice, and is essential for the normal functioning of neuronal cell membranes and activates protein kinase C which has been shown to be involved in memory function.
CarotenoidCarotenoids are organic pigments naturally occurring in plants, some algae, some types of fungus and some bacteria. They are split into two classes, xanthophylls and carotenes.
CephalinCephalin is a phospholipid found in all living cells, although in human physiology it is found particularly in nervous tissue such as the white matter of brain, nerves, neural tissue, and in spinal cord. It is the principal phospholipid in bacteria.
CardiolipinCardiolipin (bisphosphatidyl glycerol) is an important component of the inner mitochondrial membrane, where it constitutes about 20% of the total lipid.
SphingosineSphingosine is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms a primary part of sphingolipids, a class of cell membrane lipids that include sphingomyelin.
CeramideComposed of sphingosine and a fatty acid, ceramides are a family of lipid molecules found in high concentrations within the cell membrane.
SesquiterpeneSesquiterpenes are terpenes that consist of three isoprene units.
LycopeneLycopene is a bright red carotenoid pigment, a phytochemical found in tomatoes and other red fruits. It is the most common carotenoid in the human body and is one of the most potent carotenoid antioxidants.
XanthophyllXanthophylls (originally phylloxanthins) are yellow pigments from the carotenoid group.
ThromboxaneThromboxane is a member of the family of lipids known as eicosanoids. It is named for its role in clot formation.
LeukotrieneLeukotrienes are eicosanoid lipid mediators produced in the body from arachidonic acid by the enzyme 5-lipoxygenase. These substances may be responsible for a number of the effects of asthma and allergies.

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