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Chapter Four: Carbohydrates
Terms:
Dehydration (or Condensation) Synthesis: An OH group from one monosaccharide and an H atom from another monosaccharide combine to create a molecule of H 2 O. The two monosaccharides bond together with a single O atom to form a disaccharide Diabetes: Inability to produce insulin
o Type 1: Born without the ability to produce insulin
o Type 2: Called adult onset diabetes, an insulin “resistance” developed with age
Fiber: delays gastric emptying; “moves things along” in the digestive tract which is good for digestive health; two kinds: insoluble (cellulose) and soluble (fermentable) Fructose: Sweetest of the three monosaccharides Galactose: A monosaccharide found in honey and barley Glucagon: Pancreas releases this to stimulate liver to break down glycogen and release glucose into the blood Glucose: A monosaccharide; always in blood; called blood sugar Glycemic Index: Foods are rated on this scale by their glucose metabolism; Low glycemic index = slow glucose metabolism = good (peanuts, yogurt), high G.I. = fast G.M. = bad (white bread) Glycogen: stored/excess glucose in animals; “animal starch”; 2/3 of body’s glycogen is stored in muscles, other 1/3 stored in liver Hydrolysis: A disaccharide is split into two monosaccharide molecules with H added to one and OH to the other (from a water molecule) Hypoglycemia: not enough sugar in the blood, opposite of diabetes Insulin: Released by pancreas to send a message to the body to use the glucose in the blood; if glucose is not needed, it is stored in cells as fat or as glycogen Isotopes: Molecules of the same molecular formula but with different structures; Glucose, fructose and galactose all are C 6 H 12 O 6 but are arranged differently Ketone Bodies: Fragment of broken down fat molecules; in excess, result in ketosis which causes the body pH to become too acidic Lactose: A disaccharide; glucose + galactose; found in milk Lactose Intolerant: Someone who is unable to make the enzyme lactase that breaks down lactose Maltose: A disaccharide; glucose + glucose; found in beer Oligosaccharide: a small polysaccharide Saccharides: sugars; the building blocks of carbohydrates; composed of C, H & O Starch: Form of glucose in plants Sucrose: A disaccharide; glucose + fructose: table sugar
Concepts:
Carbohydrates have 4 kcals of energy per gram Carbohydrates are organic molecules Building blocks of carbs: glucose A macronutrient; measured in grams, g, (not micrograms, μg)g) Carbohydrates look like a hexagon, or multiple hexagons linked together Disaccharides are broken down in the small intestine, monosaccharides enter the capillaries of the intestinal villi, monosaccharides travel to the liver via the portal vein, in the liver galactose and fructose are converted into glucose Monosaccharides digest the fastest because they are in their simplest form and are able to go directly into the blood stream Health Effects of Carbohydrates
o Sugar = Energy; excess produces fat and tooth decay; Limit intake
o Fiber = Slowed digestion; good for digestive health; Make sure to get adequate amount
o Starch = energy, vitamins, minerals, fiber; protect body from heart disease, diabetes,
stroke, colon cancer; Make sure to get adequate amount Recommended Intake of Carbohydrates:
o 45% - 65% of total calories
Monosaccharides vs Disaccharides
o Glucose
o Fructose
o Galactose
o Maltose (glu + glu)
o Sucrose (glu + fru)
o Lactose (glu + gal)
Number of bonds per atom
o Carbon: 4
o Nitrogen: 2
o Oxygen: 2
o Hydrogen: 1
Carbohydrates measured in grams (not micrograms) because they are a macronutrient Pictures:
Chapter Five: Lipids
Pictures:
Phospholipid Cholesterol (a sterol) Glycerol
Terms:
Adipose: The term for fat tissue stored as energy after meals; stored as triglycerides Cholesterol: Human sterol, which is used in cell membranes; also makes vitamin D & bile Fat Soluble Vitamins: A, D, E, and K; Your body does not flush these vitamins out if you consume too much of them, just keeps storing them in fat tissue Fat-Soluble Vitamins: A, D, E & K; if you consume too much, your body does not excrete the excess; can be toxic; the same bodily functions these vitamins promote, they damage in excess Glycerol: The backbone for triglycerides; 1 glycerol + 3 fatty acids = 1 triglyceride + 3 H 2 O Ketosis: Sickness caused by carbohydrate deprivation in diet; fat is used for energy and not completely broken down; fragments stay in blood called ketones Linoleic & Linolenic: See Omega-3 &- Lipoprotein Lipase: Hydrolyzes triglycerides Lipoproteins: Proteins attached to lipids that are constantly in the blood stream; see below Micelles: A combination of bile and large lipids (such as monoglycerides and long-chain fatty acids), which makes the lipids soluble in water so that they can can penetrate the watery solution covering the absorptive cells in the small intestine, and be absorbed into lymph system Omega-3 & -6: Unsaturated fatty acids also known as, linoleic & linolenic, respectively; numbers refer to the placement of the double bond (after the 3rd^ or 6th^ Carbon) Phospholipids: (see above picture, left) used in cell membranes; soluble in fat and water; used as emulsifiers(things like bile that allow water and fat to mix) in the food industry (such as lecithin, found in egg yolks) Saturated Fat: A fat molecule in which all of the carbons in the fatty acid tail are saturated with hydrogens, aka no double bonds; bad for you; ex) butter, tropical oils, meat, whole milk; increases LDL cholesterol, promoting blood clotting
Sterol: Identified by its four-membered ring (see above picture, middle); Also see cholesterol Trans Fats: Saturated fats synthesized from unsaturated fats by bombarding the double bonded carbon with extra hydrogens, until the double bond is broken and reattached to the hydrogen; originally made because it made baked goods and icing look and taste better; bad for you because they increase LDL cholesterol Triglycerides: A type of lipid consisting of glycerol backbone (see above picture, on the right) and three fatty acid “tails”; these are what is store in adipose tissue as fat; formed through a series of dehydration synthesis reactions (See dehydration synth. in carbohydrates section) Unsaturated Fat: A fat molecule in which the fatty acid tails contain one or more double bonds; monounsaturated means one double bond, poly- means more than one; (see picture above on the left; bottom tail is unsaturated, top tail is saturated); good for you; ex) olive oil, avocado Concepts:
Fat has 9 kcals of energy per gram
Lipids are organic molecules
Portion of Diet: 20 – 35%
Building blocks of lipids: fatty acids
A macronutrient; measured in grams, g, (not micrograms, μg)g)
Fat breakdown in digestion
o Mouth: Lingual Lipase
o Stomach: Gastric Lipase
o Small Intestine: Bile, Pancreatic Lipase & Hydrolysis
Our bodies have a virtually unlimited ability to store fat for energy
Absorption of Fat in the small intestine
o Glycerol and small lipids (short- and medium-chain fatty acids) are absorbed
directly into the blood stream through capillaries
o Bile (an emulsifier) combines with large lipids (long-chain fatty acids and
monoglycerides) to form micelles in order to penetrate the watery surface
covering the cells of the small intestine and be absorbed into lymphatic system
Functions
o Skin insulation
o Shock absorption
o Energy (after all glucose is
depleted)
o Make up cell membranes
(phospholipids)
o Transport vitamins (A, D, E, K)
Lipoproteins: Four Types
o Low-Density Lipoproteins (LDL); bad cholesterol; body needs it but bad in excess
o High-Density (HDL); good cholesterol; removes LDL’s, anti-inflammatory
Functions:
o Structure (hair, skin, bones)
o Receptors (proteins in cells identify every cell in your
body as your own)
o Membrane Transport (lipoproteins, chylomicrons)
o Hormones (Insulin, glucagon)
o Antibodies
o Maintain pH (change in pH can denature proteins;
become dysfunctional)
o Enzymes (digestion)
Dietary Insufficiency:
o Marasmus
o Kwashiorkor
o Infections (no proteins means no antibodies)
o Weak immune system (no proteins means no antibodies)
4 Steps in Building protein (see image above)
o Primary: DNA identifies the amino acids needed and lines them up in a chain
o Secondary: The primary chain folds up in either an accordion/pleated or spiral shape
o Tertiary: The secondary shape is folded up even more
o Quaternary: Multiple tertiary amino acids combine to form one protein molecule
Proteins become denatured by:
o Heat (cooking a steak or when your body raises its temperature to denature viral
proteins when you’re sick)
o pH (adding lemon juice to tenderize meats or your body’s use of hydrochloric acid in
your stomach to digest protein)
o Pulling/Stretching (using a meat mallet to tenderize steak)
Absorption of Protein
o Amino acids absorbed in small intestine
The ones that can be used are used, but those not used go to the liver Waste products of digestion of proteins
o Ammonia (NH 3 )
o Carbon Dioxide CO 2 (O=C=O)
o Urea (NH 2 —[C=O]—NH 2 ) *two ammonia + one CO 2 = urea + one water molecule
When consuming a high-protein diet, you must drink a lot of water to help you kidneys get rid of waste products Sources of Protein
o Meat, poultry & egg whites
o Whey protein (plant source)
o Oats
