lipids function - Answers -hormones: structural component
-digestion
-energy
-structural elements
role of lipoproteins - Answers transport lipids
atherosclerosis - Answers plaque buildup of fat and cholesterol on artery walls
-reduces diameter of the lumen of the artery
-inner space becomes smaller and puts greater pressure on the artery walls = will require more
energy for blood to travel through
-key component in cardiovascular diseases:
myocardial infarctions; artery blockage leading to heart
cerebrovascular disease: artery blockage leading to brain
peripheral vascular disease: outside of the main trunk (arms and legs)
lipids - Answers -soluble in organic solutions
-nearly insoluble in water (think of oil mixing with water)
-contain non polar carbon-hydrogen bonds: produce fatty acids and/or alcohols when
hydrolyzed
-some also have polar groups: affinity for water and organic solutions (ex. phospholipids and
cholesterol)
-6 groups
6 groups of lipids (only need to know first 4) - Answers -cholesterol
-fatty acids: saturated and unsaturated
-acylglycerols: triglycerides and phospholipids (glycerol backbone with phosphorus and nitrogen
components)
-prostaglandins: big components of platelets
-sphingolipids
,-terpenes
lipid absorption - Answers dietary cholesterol and triglycerides
-triglyceride absorption is efficient
-cholesterol absorption is less efficient
*emulsification* (lipid absorption) - Answers -occurs prior to absorption in the small intestine
-occurs by pancreatic lipase: released and enters the small intestine to convert triglycerides into
monoglycerides
-*triglycerides* are converted to monoglycerides, glycerol and fatty acids
-*cholesteryl esters* are transformed to free cholesterol: makes cholesterol soluble
micelles (fill in blank) - Answers lipid absorption generates amphipathic ________
-unesterified (free) cholesterol
-fatty acids
-monoglcyerides
-phospholipids
-bile acids
-come into contact with intestinal villa and are absorbed (resemble triglycerides)
lipid absorption process - Answers -villa increase surface area in small intestine
-pancreatic lipase converts triglyceride into glycerol and free fatty acid
-take broken down pieces and add cholesterol and bile salt
-micelle is developed and gets absorbed via intestinal villa
-micelles get converted to a chylomicron: packaged with triglycerides, phospholipids and
apolipoprotein B-48 --> secreted into lymphatic system --> enter circulation
--> delivered to the liver and tissues
cholesterol - Answers unsaturated steroid alcohol containing 4 rings
-membrane component of all cells: very important part of the structure of all cells throughout
the body
-consumption of cholesterol is important but excess can be harmful to humans
, -synthesized almost exclusively by animals
-not a source of fuel
cholesterol synthesis - Answers -performed by all cells especially liver and intestine
-multiple stages
-second stage contains enzyme *HMG-CoA reductase*: enzyme is targeted for cholesterol
therapy and lowers overall cholesterol production
-HMG-CoA inhibits action of statin drug family, which is medicine used for cholesterol
*esterification* of cholesterol - Answers part of INTRACELLULAR cholesterol transport and
REVERSE cholesterol transport pathways
-forms cholesteryl ester
within the cells: stored in intracellular lipid drops
within the (circulation) plasma: binds to high density lipoproteins (HDL)
*catabolism* of cholesterol - Answers end of REVERSE cholesterol TRANSPORT pathway
-last step of the pathway
-most cholesterol returns to the liver: converts to bile acids and is absorbed in the small
intestine
-some cholesterol is excreted into the bile directly: can be made soluble by bile acids
gallstones (fill in blank) - Answers when cholesterol in the bile excess the capacity to be made
soluble, ______ form
-too much cholesterol and not enough bile acid to break it down
-reached in-saturation point and body takes bile solution and forms it into a solid phase
fatty acids - Answers linear chains of carbon-hydrogen bonds terminating in carboxyl group
-general structure is RCOOH (R is the alkyl chain and gives the fatty acids their properties)
-vary in length
-most are synthesized in the body
saturated fatty acids - Answers -no double bonds
-flexible and rotate freely