Question | Answer |
Sterols | type of lipid found in plants and animals |
structure of unsaturated fatty acids | contains carbons not saturated with H |
what causes things to go rancid? | oxygen damage |
what mostly contains saturated fatty acids? | animal fats
tropical oils |
structure of saturated fatty acids | carbons in a chain bound to 3 H |
characteristic of long-chain fatty acids | solid at room temperature |
characteristics of medium-chain fatty acids | -solid when chilled
-liquid at room temp |
# of C in a medium-chain fatty acid | 8-12 C |
short-chain fatty acids remain what state at room temp? | liquid |
carbon chains of fatty acids vary in length from ___ to ___. | a few to 20 or more |
# of C in short-chain fatty acids | 4-7 C |
Diglyceride | 2 fatty acids attached to the glycerol |
monoglyceride | one fatty acid attached to the glycerol |
structure of triglycerides | 3 fatty acids attached to glycerol molecule |
typical american diet contains ___% from fat? | 34% |
calories per gram of fat | 9 calories |
lipid | chemical term for fat |
phospholipids and membranes | form lipid bilayer in membranes, helping to regulate what can pass into and out of the cell |
what are phosphoglycerides used for? | emulsifiers |
what is the major class of phospholipids? | phosphoglycerides (ex. lecithin) |
structure of phospholipids | lipids attached to a phosphate group |
what evidence has been found about trans fats? | they raise blood cholesterol levels and increase the risk of heart disease |
hydrogenation | addition of a hydrogen which causes some double bonds to become saturated
-this creates trans fats |
essential fatty acids and type of fatty acid | omega-3 & 6
-unsaturated |
Do sterols dissolve in water? | No |
Cholesterol is a type of ___ found only where? | sterol; animals |
Where is 90% of cholesterol found in the body? | cell membranes |
Plant sterols help reduce what? | cholesterol levels |
lipoproteins | transport particles for water-insoluble lipids |
How are lipoproteins created? | combination of water-insoluble lipids, phospholipids, and proteins |
What do lipoproteins carry? | triglycerides, cholesterol, fat-soluble vitamins |
Where do lipoproteins travel? | from the small intestine and takes stored lipids from the liver |
chylomicrons | combination of diet-derived triglycerides, cholesterol, and phospholipids, with small amount of protein |
What do chylomicrons transport? | long chain fatty acids |
Where do chylomicrons go? | to the lymphatic system and into the blood stream without passing through the liver |
What do chylomicrons deliver? | triglycerides to the body's cells |
What is the importance of the liver to lipids? | the liver is the major lipid producing organ |
very low density lipoproteins (VLDLs) | triglycerides produced in the liver that are incorporated into entities |
What is the purpose of VLDLs? | transports lipids out of the liver and delivers them to cells in the body |
lipoprotein lipase | enzyme that removes triglycerides from VLDLs |
intermediate-density lipoproteins (IDLs) | created from lipoprotein lipase removing triglycerides from VLDLs |
low-density lipoproteins (LDLs) | the remainder of IDLs that are not returned to the liver |
What do LDLs contain? | less triglycerides and more cholesterol than VLDLS |
What is the purpose of LDLs? | deliver cholesterol to the cells |
Blood levels and LDLs | if the amount of LDL cholesterol in the blood exceeds the amount that can be used by the cells, it results in a high level of LDLs |
What serum levels have been associated with increased risk for heart disease? | high levels of serum LDLs |
What is really hard for most cells to break down? | cholesterol |
How is cholesterol eliminated from the body? | it is returned back to the liver so it can be eliminated |
high-density lipoproteins (HDLs) | performs a reverse cholesterol transport |
Blood levels and HDLs | help to prevent cholesterol from depositing in the artery walls |
What serum levels have been associated with decreased risk for heart disease? | high serum levels of HDLs |
What is the classification of most lipids in the body and where are they stored? | triglycerides; adipose tissue |
Purpose of adipose tissue | body shape
provide stored energy
insulate body
protect internal organs from shock |
What is used to lubricate body surfaces, like the mucus membranes? | lipids |
What is used to make several hormones, like sex hormones and cortisol? | cholesterol |
What helps to regulate blood pressure and clotting? | polyunsaturated fatty acids |
What is the significance of essential fatty acids? | important for growth, skin integrity, fertility. and the structure/functions of cell membranes |
eicosanoids | made from omega-3 and 6 fatty acids, they help to regulate blood clotting and pressure plus immune function |
omega-3 scientific name | alpha-linolenic acid (18 C) |
omega-6 scientific name | linoleic acid (18 C) |
What happens if you have essential fatty acid deficiency? | dry, scaly skin, live abnormalities, poor wound healing, growth failure in infants and impaired hearing or vision |
Most fatty acids contain how many carbons in a chain? | 18 |
What can be used to form ATP? | fatty acids and glycerol |
What begins the metabolic pathway to produce ATP? | beta oxidation |
Fasting stores and lipids | breaks down glycogen, then when those stores are gone, breaks down protein (BAD) |
Feasting stores and lipids | builds glycogen stores |
Aterosclerosis | disease where lipids and fibrous materials are deposited in artery walls |
Body and plaque buildup | if there is a plaque buildup, the body has to work harder and this often causes heart disease |
How are blood lipid levels assessed? | by a blood panel and statistics |
Dietary factors to reduce the risk of heart disease | polyunsaturated & monounsaturated fats
plant foods
B vitamins
antioxidants
moderate alcohol
fiber |
dietary factors that increase the risk of heart disease | cholesterol (connected to saturated fat)
saturated fat
trans fat
sodium
excess sugar
excess energy |
What has evidence to be a tumor promoter and initiator? | dietary fat |
What is the max percentage that diet can decrease the risk of cancer? | 25% |
How much of the diet came from fat in the 1970s? | 42% |
Who has the highest fat diet? | infants |
What are the nutrition facts labels based on? | 1968 RDAs |
fat-free | contains less than 0.5g of fat per serving |
low-fat | contains 3g or less of fat per serving |
percent fat free | may be used to only describe foods that meet the definition of fat-free or low-fat |
reduced or less fat | contains at least 25% less fat per serving of the original or reference product |
saturated fat-free | contains less than 0.5g saturated fat and 0.5g trans fat per serving |
low saturated fat | contains less than 1g of saturated per serving and contributes less than 15% kcals from saturated fat per serving |
reduced or less saturated fat | contains at least 25% less saturated fat than regular or reference product |
cholesterol-free | contains less than 2mg of cholesterol and 2g or less saturated fat per serving |
low cholesterol | contains 20mg or less of cholesterol and 2g or less of saturated fat per serving |
reduced or less cholesterol | contains at least 25% less cholesterol than the regular or reference product and 2g or less of saturated fat |
lean | contains less than 10g of fat, 4.5g or less of saturated fat, and less than 95mg or less of cholesterol per serving and per 100g |
extra lean | contains less than 5g of fat, less than 2g saturated fat, and less than 95mg of cholesterol per serving and per 100g |
What comprises reduced-fat food? | fat removed, fat replaced or contains fats that cannot be digested or absorbed |
What are fat substitutes based on? | carbohydrate-, protein-, or fat-based |
What do fat substitutes do? | reduce the absorption of fat-sluble vitamins |
What is an example of a fat substitute? | Olestra (sucrose polyester) |
What can cholesterol be used to make? | vitamin D, hormones, bile acids |
what percentage of what is digested/absorbed? | 95% (not dependent on how much you eat) |
gastric lipase | acts on triglycerides containing short and medium chain fatty acids |
where does gastric lipase work best? | acidic environments |
What type of fatty acid chain is not affected by the stomach? | long chain fatty acids |
Where does most digestion happen? | small intestine |
where is the primary site of fat digestion? | small intestine |
CCK and pancreas | stimulates pancreas to release pancreatic lipase |
pancreatic colipase | released to help facilitate lipase enzyme action |
CCK and gallbladder | stimulates the release of bile to help emulsify fats |
What is fat broken down into? | monoglycerides and fatty acids |
What is a big requirement for a fat to be absorbed by the body? | it must be completely broken down |
What are some components used to replace fats? | water
starch derivatives
fiber
protein
engineered fats |
What is the RDA for fat? | none |
What is the AI for omega-3? | 1.6g/ day men
1.1g/ day women |
What is the AI for omega-6? | 17g/ day men
12g/day women |
myristic acid | 14:0 (coconut oil/ nuts/ animal plant fats) |