BIOL 236 Nutrition Exam #2 Flashcards
What is the AMDR range and calorie count per gram for lipids?
AMDR: 20-35%
9 Cals per gram
What is the difference between visible fats v. hidden fats in foods? Provide examples.
Hidden: don’t realize
- avocados
- almonds
- potato chips
Visible: realize
- butter
- steak
- oil
What does a triglyceride structure look like?
- 3 fatty acids attached to glycerol (fats can be same or diff)
- molecule of H2O is releases w/ fatty acids to glycerol (called esterification)
- hydrolysis is reaction that releases fatty acids from glycerol
What is the chemical and functional differences between saturated, trans, and unsaturated fats?
Saturated: hydrocarbon chain is saturated with hydrogens, single bonds between all carbon atoms in the chain
- straight FA chain
- solid at room temperature
- slow spoiling
- animals fats and tropical oils
- unhealthy
Unsaturated: hydrocarbon chain is not saturated with hydrogens, at least one double bond between the carbon atoms in one FA chain of the triglyceride
- bent FA chain
- liquid at room temp
- less resistance to spoiling
- plant oils
- healthy
Trans: hydrogenation (bubbles H-gas into oil to artificially saturate oils)
- we don’t have an enzyme to deal with trans-bonds so our body puts them into arteries
- increases bad and lowers good cholesterol
- cost less
- FDA limits use
- hydrogens on opposite sides of double bond
- tightly packed at room temp (solid)
Draw and explain the differences between -cis and -trans bonds.
What are the structural and functional differences between omega-6 and omega-3 fatty acids? What are the ratios?
- we need it/have to eat it
- essential for eicosanoid production
- fetal retinal and CNS development
- adult nerve transmission and regulation
Eicosanoids: ‘hormone like’ but works locally - categories: prostaglandins, leukotrienes, lipoxygenases
Omega 3: first double bond is located after the 3rd carbon from the omega end
Omega 6: first double bond is located after the 6th carbon from the omega end
Ratio (6-3): is 5:1 benefit and 10:1 harmful - western diet 15:1 to 17:1
- polyunsaturated fatty acids
Omega 6: vegetable oils, butter, nuts, seeds, grains (inflammatory)
Omega 3: fish; salmon and tuna, flaxseed and chia seeds (anti-inflammatory)
What is the structure and function of phospholipids?
- lipids attached to a phosphate group
- lecithin
Functions: - emulsifiers: polar and nonpolar end
- mixes with fats and water
- doesn’t dissolve
- lipid bilayer in cell membranes, helping to regulate what can pass into and out of a cell
What is the structure and function of sterols?
Structure:
- hydrocarbons are arranged in multi-ringed structures
- main sterol is cholesterol
- blood lipid panels (cholesterol) is minimally impacted by 4 rings cholesterol like in eggs
Functions:
- sex hormones
- activate form of vitamin D
- adrenal hormones
- bile
- cell membranes
What is the process of triglyceride digestion and absorption? Include major organs, enzymes, micelle, bile, short-chain F.A., long-chain F.A., chylomicron, etc.
Mouth- a little bit
- lingual lipase: mostly active during infancy due to high fat in breast milk
Stomach- a little bit
- gastric lipase
Small Intestine- a lot!
- fat in S.I. triggers release of CCK (bile release)
- pancreatic secretions
Bile emulsifies fat:
- breaks down fat into micelles (an H2O soluble fat droplet, fat and bile)
- increases the surface area (allows pancreatic lipase to break down triglycerides to free fatty acids and monoglyceride
Absorption occurs by the bruch border of the absorptive cells (enterocytes)
Carbon chain length determines where fatty acids are absorbed into
- short and medium chain (cardiovascular system, portal vein to liver, get the ‘short pass’ able to go right through)
- long chain (re-esterified into triglycerides, formed into a chylomicron transport vesicle then into the lymphatic system)
What are the structures and functions of all 4 lipoproteins? What are the made of and what do they do.
- Chylomicrons: made in intestinal cells, transport triglycerides from intestines to lymph circulation, deposit triglycerides to skeletal muscle and adipose tissue (lipase), shrink over time as fat is pulled out, remnant ends at the liver and is deconstructed. Primary component is triglyceride; carries fat from S.I. to cells
- Very-low density lipoproteins (VLDL): transport lipids from liver to tissues- converted to IDLS or LDLS. Primary component is triglyceride; carries lipids taken up and made by liver to cells
- Low-density lipoproteins (LDL): deliver cholesterol to tissues of the body. Primary component is cholesterol; carries cholesterol made by liver and other sources to cells
- High-density lipoproteins (HDL): lipids from tissues to liver, certain glands. Primary component is protein; remove cholesterol from cells and excrete cholesterol from body
What is the difference between good & bad cholesterol levels? How could one improve this in a diet?
HDL is good; helps get rid of cholesterol
LDL is bad; leads to atherosclerosis (buildup of plaque in arteries)
We eat too much saturated fat and too little unsaturated fat. Consume too much omega-6 and too little of omega-3
What is the structure of proteins? (amino acid - quaternary structure)
Has 4 parts:
- carbon skeleton (generic amino acid), amino group, and acid (carboxyl) group
20 Amino Acids
- 9 are essential: necessary for life, need to consume bc body doesn’t make
- 11 are non-essential: body makes them (made through transamination: action of moving around NH2 (amino group))
What are protein’s functions in the human body?
- form structures (muscles and collagen)
- maintain fluid balance
- acid-base balance (buffers)
- hormones, enzymes, and neurotransmitters
- immune function (antibodies)
- transport
What is denaturing in relation to cooking and a living organism?
In cooking: proteins are denatured; physical changes due to environment like heat. Egg whites turn white on heat.
Living organism: loss of enzyme activity and reduction of enzymatic reactions. Changes structure of cell membrane and permeability.
What is complete and incomplete protein? Limiting amino acids and complementary protein pairing?
Complete= contain all 9 essential a.a.s
- from animal proteins (except gelatin)
- has a moth
Incomplete= doesn’t contain at least 1 essential a.a.s
- plant proteins (except quinoa and soy)
- limiting amino acids
- complementary protein pairing for vegetarian/vegan diets
Cells require an amino acid pool for essentials.
