Exam 2: Lipids, Digestion and Absorption, Energy Metabolism Flashcards
Fatty acids that are most common in foods and most noteworthy in nutrition have how many carbons?
18
What type of foods contain monounsaturated fats?
Olive and canola oil
Everywhere
Long chain saturated fatty acids have how many carbons? What form do they take at room temperature?
> 12
Solid
Short chain saturated fatty acids have how many carbons? What form do they take at room temperature?
<6
Liquid
How many carbons do medium chain saturated fatty acids have? What form do they take at room temperature?
6-10
They go between solid and liquid
Why are unsaturated fats generally liquids?
Double bonds create kinks in the chain, not allowing them to pack as easily as the straight chain saturated fatty acids
What kind of fatty acid is oleic acid? How many carbons does it have?
Monounsaturated
18
Where is the first double bond in oleic acid?
C9
omega-9 acid
What kind of fatty acid is stearic acid? How many carbons does it have?
Saturated
18
Why do fatty acids produce more energy than carbohydrates?
Because of the large amount of carbons and almost no oxygen
What kind of fatty acid is linoleic acid? How many carbons does it have?
Polyunsaturated
18
How many double bonds does linoeic acid have? On which carbon is the first one?
2 double bonds
omega-6
What kind of fatty acid is alpha-linolenic acid? How many carbons does it have?
Polyunsaturated
18
How many double bonds does alpha-linolenic acid have? On which carbon is the first one?
3 double bonds
omega-3
Why are omega-3 and omega-6 fatty acids essential?
The body does not have enzymes that can unsaturate (add double bonds) saturated fats before C9, therefore we must consume them - although in small amounts
Why do we need omega-3 and omega-6 fatty acids?
Functions: Cell membranes Immune function Vision Eicosanoid production Structural molecules
What kind of fatty acids are eicosanoids?
20C polyunsaturated
What do eicosanoids do?
Function like hormones (act locally); regulate blood pressure, clotting, immune response, inflammatory response, GI secretions
What pathway does aspirin block?
Stops Arachidonic acid (omega-6) from being turned into a Group 2 series eicosanoid, which then decreases blood clotting, vasoconstriction - why it is recommended to be taken during a heart attack or those at risk
What series of eicosanoids to omega-6 acids make? What are their function and name one.
Series 1 and 2 Stimulates blood clotting and vasoconstriction Thromboxane A2 (TXA2)
What is thromboxane A2 (TXA2)? When is it advantageous? When is it dangerous?
Series 1/2 eicosanoid that is made by platelets and stimulates blood clotting and vasoconstriction
Hemorrhage
Heart disease
Describe the eicosanoid pathway that omega-3 fatty acids take.
Docosahexonic acid (DHA) Eicosapentanoic acid (EPA) Group 3 series eicosanoids
What functions do group 3 eicosanoids have?
Inhibits making of group 2 series eicosanoids and therefore decrease blood clotting and risk of heart attack; could lead to hemorrhagic stroke
What are the symptoms of essential fatty acid deficiency?
Flaking itchy skin
Diarrhea
Reduced wound healing
Anemia
What are sources of omega-3 fatty acids?
Canola, soybean, flax seed oil
Fatty fish
What are sources of omega-6 fatty acids?
Everywhere, especially vegetable oil
What are sources of monounsaturated fatty acids?
Everywhere, especially olive oil
What are sources of saturated fat?
Animal fat
Coconut oil
Palm oil
What are sources of cholesterol?
Animals and animal byproducts
Lard
Butter
What is esterification? When does it happen?
A condensation reaction (water removed) forming an ester bond
Occurs when fatty acids are bound to glycerol
What components of fatty acids can cross cell membranes?
Free fatty acids
Monoglycerides
Glycerol
What are the functions of triglycerides?
Provide energy (9 kcal/g) Energy storage Insulation Protection Transport of fat soluble vitamins
What is the main phospholipid?
Phosphatidyl choline (lecithins)
What makes up a phospholipid?
1 glycerol + 2 fatty acids + 1 phosphorus containing fatty acid
What are the functions of phospholipids?
Emulsifiers (micelles)
Cell membranes
Metabolism is important in regulating cell function
Which part of the phospholipid (lecithin) is hydrophilic?
Head
Where can lecithins be found?
Egg yolks
What are the function of micelles?
Lipid digestion/transport
Food prep, cooking
How much cholesterol do we consume per day? (range)
200-400 mg/day
Name examples of sterols.
Steroid hormones: corticosteroids (stress), estrogen, testosterone, Vitamin D, bile acids, embedded in cell membranes
What is the function of vitamin D?
Steroid hormone that is needed for the absorption of calcium
What makes up a lipoprotein?
Micelle +
Apolipoproteins
Free cholesterol
Triglycerides (inside), some bound to cholesterol
Name the lipoproteins, in descending order of lipid content.
Chylomicrons
VLDL
LDL
HDL
What are the functions of chylomicrons?
Transport diet derived lipids from the small intestine to the lymphatics, then blood
Delivers diet derived lipids to tissues for use and storage
Whatever is left goes to the liver
Where are chylomicrons made?
Epithelial cells lining the intestine
What are the functions of very low density lipoproteins?
Made in liver from dietary and newly made lipids
Carries newly made lipids and cholesterol to tissues
Where are VLDLs made?
Made of leftover chylomicrons in liver
What are the functions of low density lipoproteins?
Receptor pathways: supplies cholesterol for growth and development of tissues mainly in the liver, and some other cells
Scavenged: WBCs attach to blood vessels and oxidize the lipids = plaque = atherosclerosis
Where are LDLs made?
From VLDLs that have lost their TGs to cells
What are the functions of HDLs?
Picks up cholesterol from dying cells and transfers it to other lipoproteins and takes it to the liver for excretion
Where are HDLs made?
Liver, intestine
How do lipids get to cells (adipose, muscle) from the blood vessels?
Lipoprotein lipase, an enzyme attached to the vessel wall hydrolyzes TGs (from chylomicrons and VLDLs) - recognized by certain apolipoproteins
What hormone induces lipoprotein lipase?
Insulin
What do you want in a blood lipid profile?
Total to be low as possible
HDL to be high as possible
ratio should be less than 4:1
What do you want to see in your blood lipid profile, in mg/dl, for: Total cholesterol LDL HDL TGs
Total: less than 200
LDL: less than 130
HDL: more than 40
TG: less than 150
During the fed state, how long does the clearance of blood lipids take?
10-14 hrs
How many kcal/lb does adipose tissue contain?
3,500 kcal/lb
During fasting, what delivers free fatty acids to the liver and muscle?
Albumin protein in blood
How can you improve your lipid profile?
Aerobic exercise (can increase HDL)
Soluble fiber
Statins (drugs)
