NUTR 1000 – 003Exam # 2: Study Guide Lectures: 5 - 10Lecture #5 (September 17)Chapter 4 – Carbohydrates: Sugars, Starches, and FiberCarbohydrates- Found primarily in plant-based foods- Most desirable form of energy for bodyo In the form of glucose (most abundant carb in nature); Brain & red blood cells especially rely on glucose for fuel source.- Plants convert the sun’s energy into glucose by photosynthesiso Glucose units are linked together & stored in form of starchClassification of Carbohydrates- Simple Carbohydrates (contain 1 or 2 sugar units)o Monosaccharides (1 sugar unit) Glucose, Fructose, & Galactose all contain 3 monosaccharideso Disaccharides (2 sugar units) Maltose = glucose + glucose Sucrose (table sugar) = glucose + fructose Lactose (milk sugar) = glucose + galactose- Complex Carbohydrates (polysaccharides)o Long chains & branches of sugars linked together Starch- Amylose: straight chains of glucose units- Amylopectin: branched chains of glucose units Fiber- Non-digestible polysaccharide (humans lack enzyme needed to break down fiber); e.g. cellulose, hemicellulose, lignins, gums, pectin- Dietary Fiber: naturally found in foods- Functional Fiber: added to food for beneficial effect; e.g. psyllium added to cereals- Total Fiber = dietary fiber + functional fiber- Fiber is classified by its affinity for watero Soluble fiber: dissolves in water & is fermented by intestinal bacteriao Insoluble fiber: cellulose, hemicellulose, lignins Glycogen- The storage form of glucose in animals-- Stored in liver and muscle cellso Only limited amountsLactose: principal carbohydrate found in dairy products- People with a deficiency of the enzyme lactase can’t digest lactose properlyo Lactose mal-digestion is a natural part of aging- Lactose intolerant: when lactose mal-digestion results in nausea, cramps, bloating, diarrhea, and flatulenceHow the Body Uses Carbohydrates- Glucose supplies energy for body- Hormone insulin regulates glucose in blood, which is produced & released by pancreas. Directs conversion of glucose in excess of immediate energy needs into glycogen (glycogenesis) in liver & muscle cells (limited capacity)o Rest of excess glucose converted to fatCarbohydrates Fuel Your Body Between Meals- Glucagon raises blood glucose levelso Glycogenolysis: released glycogen from the livero Gluconeogenesis: building glucose primarily from protein- Epinephrine (adrenaline)Lecture #6 (September 22) What Happens to Carbohydrates You Eat?- You digest carbohydrates in your mouth and intestineso Saliva contains amylase enzyme, which starts breaking down amylose & amylopectin into smaller starch units and maltoseo In small intestine, pancreatic amylase breaks down remaining starch into maltoseo Maltose & other disaccharides are broken down to monosaccharides and absorbed into bloodCarbohydrates Fuel Your Body During Fasting- Fastingo Liver glycogen stores depletedo Protein & fat stores are utilized for energy even though you can only fast for so long- Gluconeogenesiso Ketones (Don’t want too many) Made from fatty acids Limited glucose availability (improperly burned fat)o Ketosiso Keto-genic diets EpilepsyAmount of Carbs Needed- Minimum amount of carbs needed dailyo DRI: 130 grams per day for brain function- Simple & Complex Carbohydrates- Sources- Average Intake- AMDR- Fibero 14 grams of fiber per 1,000 calories; 28g/dayLecture #7 (September 24) Chapter 5: Fats, Oils, & Other LipidsFats - Lipids: category of compounds containing carbon, hydrogen, and oxygen that are hydrophobic (insoluble in water)- Fat is the common name for just one type of lipid, known as a triglycerideo Fats serve multiple functions in foods: Give flaky texture to baked goods Make meats tender Provide flavor and aromas Contribute to satiety- Fats and other lipids perform important functions in the body:o Energy storageo Insulationo Transport of proteins in bloodo Cell membrane structure- 3 types of lipids found in foods and in your body:o Triglycerides (fats), phospholipids, & sterolso Basic unit of triglycerides and phospholipids is fatty acidFatty Acids Are Found In Triglycerides and Phospholipids- Fatty acids: chain of carbon & hydrogen atoms with acid group (COOH at one end)o Over 20 different fatty acidso Can vary by:1. Length of chain2. Whether carbons have double or single bonds between them3. Total # of double bonds- Length & Structure of Fatty Acidso Saturated fatty acids: all carbons bonded to hydrogen  E.g. stearic acid, 18 carbons, solid at room temperature Packed tightly togethero Unsaturated fatty acids: one or more double bond between carbons (less saturated with hydrogen) More liquid at room temperature Can’t stack completely, very looseo Monounsaturated fatty acids: 1 double bond E.g. Oleic acid, 18 carbons (olive oil)o Polyunsaturated fatty acids: more than one double bond E.g. essential fatty acids linoleic & alpha-linoleic acids (soybean oil)3 Types of LipidsTriglyceride: 3 fatty acids connected to glycerol “backbone”o Most common lipid found in foods and bodyo Referred to as fats Saturated fats have mostly saturated fatty acids Unsaturated fats have mostly unsaturated fatty acidso Structure: glycerol backbone + 3 Fatty AcidsPhospholipids: have glycerol backbone but two fatty acids and a phosphorus groups- Phosphorus containing head is hydrophilic- Fatty acid tail is hydrophobic- Cell membranes made of phospholipid bilayero Lecithin: major phospholipid in cell membrane Used as an emulsifier in foods such as salad dressings to keep oils & watermixed together so they won’t separate.- Structure: Glycerol backbone + 2 fatty acids w/ a phosphate groupSterols: Composed mainly of 4 connecting rings of carbon & hydrogen - Important role in cell membrane structure, bile, sex hormones (testosterone)- Precursor of important compounds in body- Not required in diet since body makes all cholesterol needed- E.g. Cholesterol (only comes from the liver, vegetables & plants can’t produce cholesterol)What Happens to the Fat You Eat- Mouth: chewing & lingual lipase start digestion- Stomach: gastric lipase- Small Intestineo Bile acidso Pancreatic lipase- Short-chain fatty acids: less than 8- Medium Chain fatty acids: 8-12- Long-Chain fatty acids: 12+Lipoproteins transport fat through the lymph and blood- Chylomicrons: carry