Unit Exam #2 Study Guide PDF

Nutrition and Health 1. What is a Healthy Weight? Cultural Influence: Perception of a healthy weight varies by culture and time period. ○ Example: Comparison between Miss America in 1947 and 2008. American Ideal vs Reality: ○ The USA is the fattest nation globally, with...

Nutrition and Health 1. What is a Healthy Weight? Cultural Influence: Perception of a healthy weight varies by culture and time period. ○ Example: Comparison between Miss America in 1947 and 2008. American Ideal vs Reality: ○ The USA is the fattest nation globally, with 7 out of 10 adults being overweight or obese. ○ Causes of Obesity: High-fat fast food, lack of exercise, heredity. ○ Health Disorders Linked to Obesity: Cardiovascular disease, Type 2 diabetes, certain cancers. Measuring Healthy Weight: ○ BMI (Body Mass Index) = weight/height². A healthy range is 20-24, while a BMI over 30 indicates obesity. ○ Factors Affecting Weight: Diet and lifestyle. Limitations of BMI: ○ BMI does not consider muscle mass, age, gender, or body frame size. Maintaining a Healthy Weight: ○ To maintain weight, energy input should equal energy output. ○ Weight Loss Tips: Reduce calorie intake, increase exercise, eat smaller portions, avoid high-fat/sugar foods. ○ Safe weight loss: ½ - 2 pounds per week; 3500 calories = 1 pound. 2. Disorders Associated with Obesity Type 2 Diabetes: ○ What is Diabetes?: Sustained elevated blood sugar levels (glucose). ○ Normal Blood Sugar Regulation: Insulin: Lowers blood sugar, produced by the pancreas. Causes cells to take in glucose molecules ○ How: When you eat food, especially carbohydrates, your blood sugar rises. The pancreas releases insulin, which helps sugar (glucose) move from your blood into your cells. Your cells use this sugar for energy or store it for later. So, insulin helps your body absorb and store sugar, lowering blood sugar levels. Glucagon: Raises blood sugar, also produced by the pancreas. Causes liver to break down glycogen, releasing glucose into the blood ○ How: When your blood sugar gets too low (like between meals or when you're hungry), the pancreas releases glucagon. Glucagon tells the liver to break down stored  sugar (called glycogen) and release it into the bloodstream, which raises your blood sugar levels again. ○ Differences Between Type 1 and Type 2 Diabetes: Type 1: Pancreas does not produce insulin; treatment involves daily insulin injections. Usually occurs in childhood. Type 2: The body produces insufficient insulin or is resistant to insulin; treated with diet and exercise. ○ Complications from Diabetes: Blindness, amputation, kidney disease, slow wound healing, cardiovascular disease. Hypertension (High Blood Pressure): ○ Can lead to heart attacks and strokes. ○ Normal Blood Pressure: 120/80 mmHg. ○ Weight gain increases blood pressure. Heart Attack and Stroke: ○ Heart Attack: Portion of heart muscle dies due to blocked or ruptured blood vessels. ○ Stroke: Portion of the brain dies due to blocked or ruptured blood vessels. ○ Atherosclerosis: Fat and cholesterol deposits clog arteries. 3. Eating Disorders Anorexia: ○ An irrational fear of getting fat, leading to self-imposed starvation. ○ May cause organ failure, death, and amenorrhea (loss of menstrual cycle). Bulimia: ○ Binge eating followed by purging. ○ Leads to dental problems, dehydration, and electrolyte imbalances. 4. A Healthy Diet Dietary Guidelines: ○ Moderate fat intake, with low saturated fats and trans fats. ○ Eat complex carbs (whole grains, vegetables, legumes). ○ Avoid refined carbs (sugars and starches). ○ Low salt intake. ○ Adequate protein (from poultry, fish, plants), vitamins, and minerals. ○ Moderate alcohol consumption. ○ Avoid fad diets. The Dynamic Cell 1. Energy in Cells  Energy: Capacity to do work. ○ Potential Energy: Stored energy. ○ Kinetic Energy: Energy of motion. ATP (Adenosine Triphosphate): ○ Energy currency of the cell. ○ Structure: Adenine, ribose, and three phosphate groups (negatively charged). ○ ATP Cycle: ATP → ADP: Energy released when a phosphate group is removed. ADP + P → ATP: Energy added to rebuild ATP. ○ Energy Flow: Photosynthesis: Solar energy → glucose. Cellular Respiration: Glucose → ATP. 2. Metabolism Metabolism: All chemical reactions in the body. ○ Catabolism: Breaking down molecules, releases energy. ○ Anabolism: Building up molecules requires energy. Enzymes: Proteins acting as catalysts. ○ Catalyst: Speeds up a reaction without being consumed. ○ Activation Energy: Energy needed for a reaction to occur. ○ How Enzymes Work: Substrate: The molecule an enzyme acts on. Active Site: Where the enzyme binds to the substrate. Induced Fit: Enzyme slightly changes shape for a better fit with the substrate. Enzyme Functions: ○ Combine molecules, break molecules, or change one molecule into another. Enzyme-Related Problems: ○ Lactose Intolerance: Missing enzyme lactase. ○ Albinism: Missing enzyme to produce melanin. ○ Tay-Sachs Disease: Missing enzyme to break down toxic brain waste. 3. Cellular Transport Plasma Membrane: ○ Controls the movement of molecules in and out of the cell. ○ Made of a phospholipid bilayer with protein passageways. ○ Selectively Permeable: Only certain molecules can pass. Types of Cellular Transport: 1. Passive Transport: ○ Diffusion: Movement from high to low concentration (no energy required). Simple Diffusion: Small, nonpolar molecules (e.g., oxygen, carbon dioxide).  Facilitated Diffusion: Uses protein passageways for ionic/polar molecules. Osmosis: Water movement across a membrane. Isotonic: Equal solute concentration. Hypertonic: More solute outside; cell shrinks. Hypotonic: Less solute outside; cell bursts. 2. Active Transport: ○ Moves molecules from low to high concentration (requires energy). ○ Example: Sodium/Potassium pump (Na/K pump). 3. Bulk Transport: ○ Moves macromolecules in and out of the cell. ○ Exocytosis: Moving substances out of the cell. ○ Endocytosis: Engulfing substances into the cell. Phagocytosis: “Cell eating” – Engulfs solids. Pinocytosis: “Cell drinking” – Engulfs liquids. Receptor-Mediated Endocytosis: Engulfs specific molecules (e.g., cholesterol). Photosynthesis 1. Importance of Photosynthesis Photosynthesis: The process that transforms solar energy into chemical energy (glucose). Photosynthesizers: ○ Autotrophs: Organisms that produce their own food (e.g., plants, cyanobacteria, algae). ○ Heterotrophs: Organisms that acquire food from other sources (e.g., herbivores, carnivores). Role in the Food Chain: Photosynthesizers form the base of the food chain by producing energy-rich carbohydrates. 2. Structures Involved in Photosynthesis Leaves: The main site of photosynthesis. ○ Stomata: Tiny pores on the underside of leaves that allow for gas exchange (CO₂ in, O₂ and H₂O out). Chloroplasts: Organelles within leaf cells where photosynthesis occurs. ○ Stroma: Fluid inside the chloroplast. ○ Thylakoids: Membrane sacs inside the chloroplast, stacked into grana. ○ Chlorophyll: The primary pigment that absorbs light energy for photosynthesis, located in the thylakoids. 3. The Process of Photosynthesis  Photosynthesis Product: Carbohydrates, primarily glucose (C₆H₁₂O₆). ○ Electron Transfer: Electrons are removed from H₂O and transferred to CO₂ through REDOX reactions. Reduction: Gains electrons and energy. Oxidation: Loses electrons and energy. Two Stages of Photosynthesis: 1. Light Reactions: ○ Chlorophyll absorbs solar energy, exciting electrons. ○ Water is oxidized, releasing electrons and H⁺. ○ ATP is produced, and NADP⁺ becomes NADPH after accepting electrons. 2. Calvin Cycle: ○ CO₂ is absorbed and, using ATP and NADPH, reduced to a carbohydrate (glucose). 4. Harvesting Light Energy Radiant Energy (Solar Energy): Exists in different wavelengths, with visible light being a small portion of the spectrum (colors of light: ROYGBIV). ○ Energy Content: Highest for violet, lowest for red. Photosynthetic Pigments: ○ Chlorophyll a: The main pigment responsible for photosynthesis, absorbing blue and red light, and reflecting green (the color seen by our eyes). Accessory Pigments: ○ Chlorophyll b: Yellow-green. ○ Carotenes: Orange. ○ Xanthophylls: Yellow. Cellular Respiration 1. Overview of Cellular Respiration Cellular Respiration: The process that produces ATP, the energy currency of the cell. ○ Equation: C₆H₁₂O₆ (glucose) + O₂ → CO₂ + H₂O + ATP. ○ ATP powers all cellular activities. ○ Cellular respiration occurs in the mitochondria. ○ Energy Release: Glucose is broken down to produce 38 ATP per glucose molecule. Coenzymes (Electron carriers): ○ NAD⁺ becomes NADH. ○ FAD becomes FADH₂. Four Phases of Cellular Respiration: 1. Glycolysis. 2. Prep Reaction. 3. Citric Acid Cycle (Krebs Cycle). 4. Electron Transport Chain (ETC). 2. Phases of Cellular Respiration A. Glycolysis: Location: Cytoplasm. Requires 2 ATP to start. Breaks Glucose into 2 pyruvate molecules. Yield: ○ 2 pyruvate. ○ 2 ATP. ○ 2 NADH. B. Prep Reaction: Location: Mitochondria. Prepares 2 pyruvates for the Citric Acid Cycle. Yield: ○ 2 acetyl CoA. ○ 2 NADH. ○ 2 CO₂. C. Citric Acid Cycle (Krebs Cycle): Location: Mitochondria. Two turns of the cycle occur for each glucose molecule. Yield (per glucose molecule): ○ 4 CO₂. ○ 6 NADH. ○ 2 ATP. ○ 2 FADH₂. D. Electron Transport Chain (ETC): Location: Mitochondria. A series of electron carriers embedded in the membrane. How it works: ○ Electrons are released from NADH and FADH₂, passing from one carrier to another, releasing energy. ○ Oxygen is the final electron acceptor, becoming water. ○ H⁺ ions are pumped across the membrane, and as they flow back, ATP synthase produces ATP (like a revolving door). 3. Fermentation Fermentation: Anaerobic process (no oxygen) that allows glycolysis to continue, producing a small amount of ATP. Types of Fermentation: 1. Lactic Acid Fermentation: ○ Occurs in muscle cells and some bacteria. ○ Happens when there is a lack of oxygen during intense exercise. ○ Produces lactate. 2. Alcoholic Fermentation: ○ Occurs in yeast. ○ Happens when oxygen is lacking after glycolysis. ○ Produces carbon dioxide and ethanol. ○ Used in the production of bread, beer, and wine.