week three study tips Flashcards
what are the functions of lipids?
- provide energy (9kcal/g)
- efficient storage of energy
- insulation
- protection
- transport fat-soluble vitamins ADE&K
- some satiety
- flavour and mouth feel, it just tastes good!
chemically, why are saturated fatty acids solid at room temperature e.g. lard on steak or a stick of butter?
Each carbon atom is typically bonded to two hydrogen atoms. When a fatty acid has this typical arrangement, it is called “saturated”, because the carbon atoms are saturated with hydrogen; meaning they are bonded to as many hydrogens as possible. Saturated fats can stack themselves in a closely packed arrangement, due to its carbon hydrogen composition and so they can freeze easily and are typically solid at room temperature. This formation is stable and due to this reason, the melting temperature of these types of fats are increased. So they stay solid at room temperature.
in what part of the cell are phospholipids found?
the cell membrane
what risk factors place a person at risk for cardiovascular disease?
- total blood cholesterol >200mg/dl
- smoking -
- increases clotting
- increases expression of genetic link
- hypertension (>139/89) diabetes
- low HDL
- age
- family history
- blood triglycerides > 200mg/dl
- obesity
- inactivity
how can you reduce your LDL cholesterol and triglyceride levels?
- see doctor
- reduce dietary saturated fat and cholesterol
- increase mono and polyunsaturated fats in diet
- increase soluble dietary fiber
- avoid overeating
- limit alcohol and simple sugars
- small frequent meals
- include fish in diet 2x per week
how can you raise your HDL cholesterol?
- physical activity at least 45min/day 4days/week
- don’t smoke
- eat regularly
- eat less total fat
- moderate intake of alcohol
what are the enzymes and hormones involved in lipid digestion?
- enzyme lipase
- fat digesting enzyme produced by salivary glands, stomach, and pancreas
- impacts triglycerides containing short and medium chain fatty acids
- in mouth
- lingual lipase: active in infants to digest the SCFA and MCFA in milk, continued in stomach
- in stomach
- gastric lipase only hydrolyzes a small amount of fat in stomach
- activated by acidific environment
- acts on triglycerides containing SCFA and MCFA
- in small intestine
- primary site of fat digestion
- hormone CCK which stimulates release of pancreatic lipase
- intestinal lipases released
- bile acid released from gallbladder, emulsified digested fat, enterohepatic circulation
- fat is broken down to smallest units
- triglycerides –> monoglycerides & fatty acids
- phospholipids –> glycerol, fatty acids, and remianing parts
- sterols –> absorbed
- primary site of fat digestion
what are the functions and roles of fat in our body?
- omega 3
- decrease blood clotting
- reduce heart attack
- decrease inflammation
- lower triclycerides, rheumatoid arthiritis, behavioral disorders
- omega 6
- immune system function and vision
- help in fomration of cell membranes
- production of eicosanoids, involved in all important body functions
- increases blood blotting
- increases inflammatory responses
- phospholipids
- emulsifier (bile, lecithins)
- component of cell membrane
- cholesterol
- essential component of cell membrane
- forms important hormones (estrogen+testosterone, vitd)
- precursor to bile acids
what are the major and minor sites of digestion and absorption of fat take place?
- minor
- stomach/gastric lipase
- lingual lipase (mouth)
- intestinal lipases
- major
- small intestine/pancreatic lipase
what happens to fat after it is absorbed and carried in our bloodstream? where does it go? how is it stored?
- 95% of dietary fat is absorbed through diffusion as monoglycerides and fatty acids and diffused into the absorptive cells
- glycerol, SCFA and MCFA are water soluble, diffusing into the membrane and enter the blood to liver
- LCFA (12+ carbons_ reform into triglycerides, package into chlomicrons and enter lymphatic system
- not water soluble –> form micelles –> diffuse into membrane
- after diffusion, form into triglycerides, where they and cholesterol and protein form chlomicron packages and enter the lymphatic system
what is hydrogenation of lipids and what does it produce? why hydrogenate fats? what are the health implications?
- hydrogenation of fats is when hydrogen is added to the C=C carbon bonds to resemble saturated fats and stabilize the bond (C-C)
- solidifed as an oil, reduces the amount of double bonds in polyunsaturated fats
what happens to monoglycerides and fatty acids after absorption across the intestinal wall? do they reassemble or enter the bloodstream unchanged? does fatty acid chain length make a difference?
- monoglycerides are diffused into the absorptive cells. SCFA and MCFA (fewer than 12 carbons) are water soluble and can diffuse into the membrane, entering the protal system in blood to liver. LCFA (12+ carbons) form micelles and diffuse the membrane, reforming into triglycerides after diffusion and package into chylomicron pacakges to enter the lymphatic system
what is carried through lymph from intestines and what is carried directly in bloodstream?
- LCFA through lymph and SCFA, MCFA through bloodstream
what are lipoproteins and why are they needed? explain transportation of each and where/how each originates.
- lipoproteins are compounds in the bloodstream containing a core of lipids with a shell composed of protein, phospholipid, and cholesterol. it is the vehicle used for lipid transport.
- chlyomicron: carries dietary fat from small intestine to cells
- VLDL (bad): carries lipids made and taken up by the liver to cells
- LDL (bad): carries cholesterol made by the liver and from other sources to cells
- HDL (good): contributes to cholestrol removal from cells and exretes it from body
what are the health effects and sources of saturated fats?
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