Intro to Nutrition Exam 2 PDF

Chapter 6: Fats and Their Functions Basic Structure & Function of Lipids: o Triglycerides: Comprised of 3 fatty acids bound to a glycerol molecule. They provide energy, store fat, and support cell structure. o Phospholipids: Have 2 fatty acids, a glyce...

Chapter 6: Fats and Their Functions Basic Structure & Function of Lipids: o Triglycerides: Comprised of 3 fatty acids bound to a glycerol molecule. They provide energy, store fat, and support cell structure. o Phospholipids: Have 2 fatty acids, a glycerol backbone, and a phosphate group. They are key components of cell membranes. o Sterols: Complex lipids like cholesterol that play roles in cell membrane structure, hormone production, and bile formation. Classification of Fatty Acids: o Based on chain length and degree of saturation: ▪ Short-chain (12 carbons) ▪ Saturated (SFAs): No double bonds (e.g., butter, lard). ▪ Monounsaturated (MUFAs): One double bond (e.g., olive oil). ▪ Polyunsaturated (PUFAs): Multiple double bonds (e.g., flaxseed, fish oil). Fats at Room Temperature: o Solid: Saturated fats (e.g., butter, lard). o Liquid: Unsaturated fats (e.g., vegetable oils). Hydrogenation: The process of adding hydrogen to unsaturated fats, converting them into saturated fats or trans fats, which makes them more solid at room temperature. Essential Fatty Acids: o Omega-3 (alpha-linolenic acid) and Omega-6 (linoleic acid), found in fatty fish, seeds, nuts, and vegetable oils. They are critical for brain function, inflammation control, and cell membrane integrity. Functions of Fats: Energy storage, hormone production, absorption of fat-soluble vitamins (A, D, E, K), insulation, and cushioning organs.  Digestion & Absorption of Fats: Fats are broken down by bile and enzymes in the small intestine. Absorbed into intestinal cells, reassembled into triglycerides, and transported via chylomicrons in the lymphatic system. Fat Transport: Transported through the bloodstream as lipoproteins (e.g., LDL, HDL) to body cells for storage or energy use. AMDR for Fat: 20-35% of total daily calories from fat. Healthful Fat Recommendations: Emphasize unsaturated fats (especially omega- 3s), limit trans fats, and reduce saturated fats. Atherosclerosis: A buildup of plaque in arteries, caused by high LDL cholesterol, which can lead to cardiovascular disease (CVD) by narrowing blood vessels and increasing the risk of heart attack or stroke. Modifiable Risk Factors for CVD: Diet, physical inactivity, smoking, alcohol consumption, and stress. Blood Lipids: Total cholesterol, LDL (bad), HDL (good), and triglycerides. Higher HDL and lower LDL levels are better for heart health. Improving Blood Lipids: Increase physical activity, reduce saturated and trans fat intake, and consume more fiber and omega-3s. Chapter 7: Proteins Building Blocks: Amino acids (20 total; 9 are essential). Amino Acid Differences: Vary in side chains (R groups), affecting their properties. Essential vs. Nonessential Amino Acids: o Essential: Must be obtained from food. o Nonessential: The body can synthesize them. Transamination: The process of transferring an amino group from one amino acid to a keto acid, forming a new amino acid. Protein Synthesis: Amino acids are linked through peptide bonds to form polypeptides, folded into functional proteins. Protein Turnover: The continuous process of breaking down and rebuilding proteins in the body.  4 Levels of Protein Structure: Primary (amino acid sequence), secondary (alpha- helix, beta-pleated sheets), tertiary (3D shape), and quaternary (multiple polypeptide chains). Denaturation: Alteration of a protein's structure due to heat, acids, or other factors, leading to loss of function. Complete vs. Incomplete Proteins: o Complete: Contains all 9 essential amino acids (e.g., meat, eggs, dairy). o Incomplete: Lacks one or more essential amino acids (e.g., beans, grains). Mutual Supplementation: Combining plant-based protein sources (e.g., beans and rice) to ensure all essential amino acids are consumed. Protein Functions: Enzymes, hormones, immune function, tissue repair, and fluid balance. Protein Digestion & Absorption: Proteins are broken down by stomach acid and enzymes, absorbed as amino acids in the small intestine. Protein Needs: o Children, pregnant women, athletes, and the elderly need more protein. o Excess protein can lead to kidney strain and dehydration. Vegetarian Diet: People choose vegetarianism for health, ethical, or environmental reasons. Challenges include ensuring adequate intake of essential amino acids, iron, calcium, and vitamin B12. Micronutrient Characteristics: o Fat-soluble vitamins (A, D, E, K): Stored in fat, require fat for absorption. o Water-soluble vitamins (B-vitamins, C): Not stored in the body, need to be consumed regularly. o Minerals: Inorganic elements essential for various body functions. Supplementation Controversy: Overuse or unnecessary supplementation can cause toxicity and imbalances, and most people can meet their nutrient needs through a balanced diet. Chapter 8: Fluids and Electrolytes Fluid Distribution: o Intracellular fluid: Inside cells. o Extracellular fluid: Outside cells (including blood plasma and interstitial fluid). Lean vs. Adipose Tissue: Lean tissue contains more water than adipose (fat) tissue. Age & Fluid Content: Younger individuals and males generally have more body water than older adults. Solvent & Solute: o Solvent: Substance that dissolves another. o Solute: Substance dissolved in a solvent. Blood Volume & Pressure: Low blood volume can decrease blood pressure, and high volume can increase it. Fluid & Body Temperature: Fluids help regulate body temperature through sweating and evaporation. Protective Fluids: Synovial fluid (joints) and cerebrospinal fluid (brain). Acid-Base Balance: Water helps regulate pH by neutralizing acids and bases. Osmosis: The movement of water across a membrane to balance solute concentrations. Electrolytes: Sodium (Na+), potassium (K+), chloride (Cl-) are critical for nerve and muscle function. Thirst Mechanism: Controlled by the hypothalamus, stimulated by dehydration or high sodium levels. ADH: Antidiuretic hormone promotes water retention by the kidneys. Fluid Balance: Water is lost through urine, sweat, and evaporation; gained from food, beverages, and metabolism. Sodium Functions: Regulates fluid balance, nerve transmission, and muscle contraction.  Hypernatremia: High sodium levels, can lead to dehydration, confusion, or seizures. Hyponatremia: Low sodium levels, can result from excessive water intake, leading to swelling of cells. Potassium Functions: Important for nerve signaling, muscle contraction, and fluid balance. Hyperkalemia & Hypokalemia: o Hyperkalemia: High potassium, can cause irregular heartbeats. o Hypokalemia: Low potassium, can cause muscle weakness and cramping. Phosphorus Functions: Involved in energy production, bone health, and DNA synthesis. Heat-Related Illnesses: o Heat cramps: Painful muscle contractions. o Heat exhaustion: Weakness, dizziness, and nausea from dehydration and heat. o Heat stroke: Severe heat illness with organ failure and risk of death. Alcohol and Health: Moderate alcohol consumption may reduce cardiovascular risk, but excessive consumption can lead to liver damage, addiction, and other health issues. Alcohol Absorption & Metabolism: Absorbed in the stomach and small intestine; metabolized primarily by the liver via alcohol dehydrogenase. Alcohol & the Brain: Impairs judgment, motor skills, and memory, and can be addictive. Liver Function Stages: Fatty liver, alcoholic hepatitis, and cirrhosis. Fetal Alcohol Spectrum Disorders (FASD): A set of birth defects caused by alcohol exposure during pregnancy.