Chapter 6 & 7 Detailed Study Guide PDF

Detailed Study Guide for Exam: Chapters 6 & 7 Chapter 6: Nutrients, Transport, and Growth in Cells Essential Nutrients for Cells Essential Nutrient: A nutrient required for survival that a cell cannot synthesize on its own. Macronutrients: Required in large quantit...

Detailed Study Guide for Exam: Chapters 6 & 7 Chapter 6: Nutrients, Transport, and Growth in Cells Essential Nutrients for Cells Essential Nutrient: A nutrient required for survival that a cell cannot synthesize on its own. Macronutrients: Required in large quantities for cell structure and metabolism. These include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (CHONPS). Micronutrients: Needed in smaller amounts, often for enzyme function and protein structure. Examples include zinc, iron, and manganese. Autotrophs vs. Heterotrophs Autotrophs: Organisms that can make their own food using inorganic compounds (like CO₂) and energy from sunlight or chemicals (e.g., plants, algae). Heterotrophs: Organisms that obtain energy by consuming other organisms (e.g., animals, fungi). Types of Transport in Cells 1. Simple Diffusion: Movement of molecules from an area of high concentration to low concentration without energy or assistance. Examples: oxygen and carbon dioxide moving across membranes. 2. Facilitated Diffusion: Similar to simple diffusion, but involves carrier proteins or channel proteins to help large or charged molecules cross the membrane without energy. Example: Glucose transport into cells. 3. Active Transport: Requires energy (usually ATP) to move molecules against the concentration gradient (from low to high concentration). Example: The sodium-potassium pump (Na⁺/K⁺ pump), which pumps sodium out of the cell and potassium into the cell. 4. Endocytosis: The process by which a cell engulfs material from its external environment by surrounding it with a section of its membrane, which then pinches off to form a vesicle inside the cell. Phagocytosis: “Cell eating” for solid particles (e.g., immune cells engulfing bacteria). Pinocytosis: “Cell drinking” for liquids. Osmosis and Tonicity  Osmosis: The diffusion of water across a selectively permeable membrane from an area of lower solute concentration to higher solute concentration. Tonicity: The effect of solute concentration on cell shape and water movement. Isotonic: Solute concentration is equal inside and outside the cell; water moves in and out equally. Hypotonic: Lower solute concentration outside the cell; water moves into the cell, possibly causing it to swell and burst (lysis). Hypertonic: Higher solute concentration outside the cell; water moves out of the cell, causing it to shrink (crenation). Binary Fission and Bacterial Growth Binary Fission: A form of asexual reproduction in bacteria where one cell divides into two genetically identical cells. Steps include DNA replication, elongation of the cell, and division into two daughter cells. Bacterial Growth Curve: 1. Lag Phase: Bacteria are adjusting to their environment, preparing for growth. 2. Log (Exponential) Phase: Bacteria divide rapidly, and population size increases exponentially. 3. Stationary Phase: Nutrients start to deplete, and waste products accumulate; growth rate slows. 4. Death Phase: Cells die faster than they reproduce due to lack of nutrients and accumulation of toxins. Chapter 7: Metabolism and Enzymes Metabolism Metabolism: All of the chemical reactions that occur within a cell to maintain life. Anabolism: Building large molecules from smaller ones (requires energy). Catabolism: Breaking down large molecules into smaller ones (releases energy). Enzymes Enzymes: Biological catalysts that speed up reactions by lowering the activation energy. Active Site: The region of the enzyme where the substrate binds. Substrate: The molecule that the enzyme acts upon. Product: The result of the enzyme-mediated reaction. Enzyme Inhibition: Competitive Inhibition: A molecule similar to the substrate competes for the active site, blocking the substrate.  Non-Competitive Inhibition: A molecule binds to a different part of the enzyme (allosteric site), changing its shape and preventing the substrate from binding to the active site. Energy Production ATP (Adenosine Triphosphate): The energy currency of the cell, composed of adenine, ribose, and three phosphate groups. When ATP is broken down into ADP (adenosine diphosphate) and a phosphate group, energy is released for cellular work. Types of Catabolism 1. Aerobic Respiration: Uses Oxygen as the final electron acceptor in the electron transport chain. Produces a large amount of ATP (36-38 ATP per glucose molecule). Byproducts: Carbon dioxide (CO₂) and water (H₂O). Steps: Glycolysis → Krebs Cycle → Electron Transport Chain (ETC). 2. Anaerobic Respiration: Does not use oxygen; instead, uses other inorganic molecules (e.g., nitrate, sulfate) as final electron acceptors. Produces less ATP than aerobic respiration (2-36 ATP per glucose molecule). Byproducts vary depending on the electron acceptor. 3. Fermentation: No oxygen required. Only uses glycolysis, resulting in 2 ATP per glucose molecule. Pyruvate is converted into organic molecules like lactic acid or ethanol to regenerate NAD⁺ for glycolysis to continue. Examples: Lactic acid fermentation (in muscles) and alcohol fermentation (in yeast). Flu Virus and Immunity Flu Virus (Influenza): A highly contagious virus that affects the respiratory system. It evolves quickly, which is why flu vaccines need to be updated regularly. Flu Vaccine: A preventive shot that helps your immune system recognize and fight the flu virus if you’re exposed. Herd Immunity: When a large portion of the population is immune to a disease (through vaccination or previous illness), it helps protect those who are not immune by reducing the spread of the virus. Key Vocabulary and Concepts Oxidation-Reduction (Redox) Reactions: Chemical reactions where electrons are transferred from one molecule to another. Oxidation is the loss of electrons, and reduction is the gain of electrons.  Electron Carriers: Molecules like NAD⁺ and FAD that transport electrons during cellular respiration. They are reduced to NADH and FADH₂ and then donate electrons to the ETC to produce ATP. Potential Exam Questions 1. Explain the difference between facilitated diffusion and active transport. Facilitated diffusion moves molecules down their concentration gradient with the help of carrier proteins and requires no energy. Active transport moves molecules against their gradient and requires ATP. 2. What are the stages of aerobic respiration, and where do they occur? Glycolysis (cytoplasm), Krebs Cycle (mitochondrial matrix), Electron Transport Chain (inner mitochondrial membrane). 3. How do competitive and non-competitive enzyme inhibitors differ? Competitive inhibitors block the active site directly, while non-competitive inhibitors bind elsewhere on the enzyme and change its shape. 4. Why does anaerobic respiration produce less ATP than aerobic respiration? Anaerobic respiration uses inorganic molecules other than oxygen as the final electron acceptor, which are less efficient, leading to lower ATP production. 5. How do bacterial cells divide, and what are the four phases of bacterial growth? Bacterial cells divide by binary fission. The four phases of bacterial growth are lag, log, stationary, and death phases. 6. Describe how a virus replicates and how vaccines help prevent viral infections like the flu. Viruses attach to host cells, insert their genetic material, and hijack the host cell to make new viruses. Vaccines introduce a weakened or dead version of the virus to the immune system so it can recognize and fight the virus if exposed in the future. Final Tips Understand the details of how enzymes work, including active sites and inhibitors. Review the steps of metabolism, including glycolysis, the Krebs cycle, and the electron transport chain. Be prepared to explain cellular transport mechanisms and how different processes work in various cellular environments (hypertonic, hypotonic, isotonic). Study key metabolic pathways and how ATP is generated in aerobic vs. anaerobic conditions. By mastering these concepts, you’ll be well-prepared for any exam question on chapters 6 and 7!