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What are the five primary functions of lipids?
energy storage, cell membrane structure, hormone signaling, insulation, and absorption of fat-soluble vitamins.
What is the primary lipid component in cell membranes?
phospholipids
What is the chemical structure of a phospholipid?
Water soluble head (hydrophilic), two fatty acid chains, glycerol backbone,
What is cholesterol?
It is a waxy, fat-like substance that is an essential component of cell membranes and plays a role in the production of bile acids, vitamin D, and steroid hormones.
Is Cholesterol a non-essential lipid?
Yes, because it is produced by the body.
Triglycerides are the ____ abundant lipid in our diet.
most
Are Triglycerides a storage form of fat in our bodies?
Yes
What is the chemical structure of Triglycerides?
Three fatty acid chains, connected to a glycerol molecule, the "head" is a glycerol molecule, which is a polar, hydrophilic (water-loving) component, while the "tails" are three fatty acid chains, which are nonpolar and hydrophobic (water-repelling).
Sterols
Cholesterol is the primary dietary sterol.
Saturated vs Unsaturated fatty acids
the chemical structure in saturated, no double bonds between carbon atoms, fully saturated with hydrogen atoms. Physical state, solid at room temp. Unsaturated: one or more double bonds between carbon atoms. Physical state, liquid at room temp.
Role of bile acids vs Lipase
bile acids are produced in the liver, lipase is produced by the pancreas.
Bile acids emulsify fats by creating tiny droplets. Lipase is the enzyme that chemically breaks down the fat molecules.
What are the two essential fatty acids?
Omega-3, and Omega-6 fatty acids
What are the most recommended lipids for the typical american diet?
Seafood omega-3 fatty acids
What is the primary GI site for fat absorption?
Small intestine
What are four lipoproteins?
LDL (low-density lipoproteins), VLDL (very low-density lipoproteins), HDL (high-density lipoproteins), and ChylomicronWhere
Among the four lipoproteins ____ picks up cholesterol from the body cells and returns them to the liver.
HDL
Where does chylomicron originate from?
Small intestine
Both chylomicron and VLDL transport primarily _____
Triglycerides
VLDL originates from the ______
Liver
HDLs originate from where
Small Intestine
Where do LDL cells come from?
The Liver
What lipoprotein has the highest percent of triglyceriddes?
Chylomicron
What lipoprotein has the highest percent of protein?
HDL
What is the AMDR for dietary lipids?
20-35%
According to the acceptable Macronutrient Distribution Rages(AMDRs), what is the minimum amount of trans fat in grams recommended for an 3600-calorie diet? 9 calories/g fat
3600 x .02 = 720
720/9 = 80 g
According to the AMDRs, what is the maximum amount of fat in grams recommended for an 900-calorie diet? 9 calories/g fat
900 x .02 = 18
18/9 = 2 grams
What are the dietary resources of trans fat?
Partially hydrogenation not fully hydrogenation
What is the chemical structure of trans fat?
Unsaturated fats with trans double bonds instead of cis-bonds, creates a straight fatty acid chain not a bent one.
Most of the unsaturated fatty acids found in nature are _____
cis fats
What are the harmful effects of consuming trans fats?
Raise levels of LDL cholesterol and lower levels of HDL cholesterol in the blood. This increases the risk of heart disease more than any type of fat. As little as 1% of total calories from trans fat can increase risk of heart diseases, stroke, or sudden death from these illnesses.
What was the most important finding in the Bogalusa Heart Study?
Fat plaques form in the vessels of children.
Cardiovascular disease (CVD) is ____ term
Long term, not developed over night. The long-term narrowing (affecting blood flow) and loss of elasticity (increasing blood pressure) in blood vessels.
When does CVD develop
It develops over many years often beginning in childhood.
How is the plaque formed in CVD?
LDLs accumulate in the blood, they become oxidized, which causes inflamantion and inqury to the vessel wall. Plaque begins as lipids from LDL accumulate here.
What does plaque in a vessel lead to in CVD?
The plaque will slowly build up more over time leading to a plaque rupture or clot formation that will further block blood flow through the artery. This leads to a heart attack, when an artery supplying blood to the heart is completely clot. Or a stroke, when an artery supplying blood to the brain is completely clot.
Modifiable risk factors for CVD?
Diet, obesity, activity, smoking, alcohol consumption, Heart-related conditions (high blood pressure, blood glucose, LDL cholesterol)
Dietary suggestion for CVD?
Keep saturated fats below 7% of calories but do not completely eliminate saturated fat from the diet.
what are the functions of proteins?
structural support, biochemical catalysts, hormones, enzymes, building blocks, initiators of cellular death.
What is the primary function of amino acids?
They are the building blocks for protein. Amino acids form proteins through peptide bonds.
Are there essential and non-essential amino acids?
Yes
What is the chemical structure of amino acids?
Central carbon, amino group, carboxyl group, and R-group(side chain) the side chain is the difference between each amino acid.
How can the r-group in amino acids differ
polar, non-polar, charged
What is protein denaturation?
the process of changing the three-dimensional structure of protein. Its second and third structure are destoryed but first remains intact.
what are the factors that cause protein denaturation?
heat (high temps), acids and bases (changes in pH), alcohol, salt, mechanical agitation, UV light, reducing and oxidizing agents, heavy metal ions.
What is the main purpose of protein turnover in the body?
to maintain a constant supply of functional proteins by continuously breaking down old or damaged proteins and replacing them with new ones. Eliminates damaged proteins.
The protein recommendation for elderly individuals over 65 years old to help maintain lean body mass is ____
1.2 g/kg/day
EX: Protein RDA for a healthy adult is .8 g/kg/day. What is the protein RDA (in grams) for an adult who weighs 154 punds, assuming the adult is not an athlete and is at a healthy body weight? (2.2 lb = 1kg)
What is the function of acidic juices?
To help break down proteins during digestion, in the stomach
What is the function of pepsin?
breaks down protein molecules by cleaving peptide bonds. In the stomach
What is the function of protease?
an enzyme that breaks down proteins into smaller peptides or amino acids by cleaving peptide bonds in the protein chain. In the stomach.
Proteins are digested into individual amino acids and enter the _______
blood stream
What is the fate of amino acids?
Excess amino acids are not stored in the body, they are broken down to C+ amino group
what is nitrogen balance
the difference between the amount of nitrogen consumed through diet and the amount of nitrogen excreted from the body. Positive means more protein is being gained and negative means more protein is being lost.
Which individuals are least likely to have a positive nitrogen balance?
a growing child
What is a complete protein?
a food source that contains all nine essential amino acids that the body needs to function. (meat, poultry, fish, eggs, dairy products, soy quinoa, buckwheat)
Can incomplete proteins be combined to form a complete protein source?
No
Kwashiorkor what is it
Acute protein-Energy Malnutrition (PEM), gets enough calories but not enough protien
Symptoms of Kwashiorkor
Wasting(loss of muscle mass), fatty liver, edema (swelling)
Marasmus what is it
a severe and prolonged deficiency of both calorie and protein intake
Marasmus symptoms
“skin and bones“, fat depletion, muscle wasting, impaired brain development + learning ability, little activity
Which is not a primary function of lipids
Acts as enzymes
What fatty acid would be the most solid at room temp?
Coconut oil
What is responsible for breaking down triglycerides into monoglycerides and free fatty acids
Pancreatic lipase
What is the correct path of an absorbed triglyceride
Chylomicron, micelle, lymph, bloodstream, liver, vldl, ldl, back to liver
Chylomicrons are synthesized within the
Liver
According to amdrs what is the maximum amount of fat grams g recommended for a 1800 kcalorie diet?
70
Lecitithin is a sterol which is used commercially as an emulaifier
Phospholipid, emulsifier
Characteristics of hydrogenated oils include all of the following except
They are converted to a form of cholesterol during the hydrogenation process
What is the less abundant fatty acid in American diet
Omega 3
What is the correct order for the stages of development of atherosclerosis
Ldl cholesterol is oxidized, foam cells form, plaque forms, blockage of arteries
Two proteins contain the same number of the 20 different amino acid, yet they do not have the same three dimensional structure and function. This is because
The proteins differ in the sequence of amino acid in the polypeptide chain.
What is true about protein digestion
Stomach acid unfold a protein, individual amino acid leave the mucosal cells through transport proteins and enter the blood, brush border proteases digest short peptides into tripeptide, dipeptides and individual amino acids
The amdr for protein intake is
10-35 total calories
What individual is not in positive nitrogen balance
A 35 year old man on a high protein diet with normal levels of physical activity
Cofactors are often
Minerals
Coenzymes are often
Vitamins
Enzymes are what that facilitate chemical reactions without being altered thenselves
Proteins
What type of reaction make up metabolism and are used to generate atp
Redox reactions
Clycolysis creates how many pyruvates
2
Glycolysis creates how many atp
2
The citric acid cycle occurs in the
Mitochondrial matrix
What metabolic pathway produces the most atp from a molecule of glucose
Electron transport train
At the completion of the citric acid cycle, the majority of the chemical energy that was originally present in the metabolic fuels is now found in
Reduced coenzymes
