Summary Exam 2 Study Guide Key - BIOS242 / BIOS 242 (Latest 2023 / 2024) : Fundamentals of Microbiology with Lab - Chamberlain

Microbiology Exam Two Study Guide Key: Course Outcome 5: Analyze the physical and biochemical requirements of a given microorganism. 1. Sources of Carbon and Energy: - Heterotrophs: Microorganisms that obtain carbon from organic sources (e.g., glucose). - Autotrophs: Microorganisms that use carbon dioxide as their carbon source and obtain energy from sunlight (phototrophs) or chemical reacHons (chemotrophs). 2. Types of Microorganisms based on Energy and Carbon Sources: - Photoautotrophs: Use sunlight for energy and carbon dioxide for carbon. - Chemoautotrophs: Use chemical reacHons for energy and carbon dioxide for carbon. - Photoheterotrophs: Use sunlight for energy and organic compounds for carbon. - Chemoheterotrophs: Use organic compounds for both energy and carbon. - Saprobes: Decomposers that obtain nutrients from dead organic maNer. - Parasites: Depend on living hosts for nutrients. 3. Macronutrients and Micronutrients: - Macronutrients: Elements required in large amounts (e.g., carbon, nitrogen, phosphorus). - Micronutrients: Elements required in small amounts (e.g., iron, zinc). 4. Effects of SoluHons on Cells: - Isotonic: No net movement of water into or out of the cell. - Hypertonic: Water moves out of the cell, causing it to shrink (plasmolysis). - Hypotonic: Water moves into the cell, causing it to swell and potenHally burst (lysis). 5. Organism Requirements in RelaHon to Temperature, Pressure, pH, and Oxygen: - Temperature: a. Psychrophiles: Grow best in cold temperatures. b. Thermophiles: Grow best in hot temperatures. c. Hyperthermophiles: Grow best in extremely hot temperatures. d. Mesophiles: Grow best in moderate temperatures (e.g., human body temperature). - pH: a. Acidophiles: Thrive in acidic condiHons. b. Alkalinophiles: Thrive in alkaline condiHons. c. Neutrophiles: Grow best in neutral pH condiHons. - Pressure: a. Barophiles: Adapted to high-pressure environments (e.g., deep-sea organisms). b. Halophiles: Thrive in high-salt environments. - Oxygen: a. Aerobes: Require oxygen for growth. b. Anaerobes: Cannot tolerate oxygen. c. FacultaHve Anaerobes: Can grow with or without oxygen. d. Obligate Anaerobes: Cannot grow in the presence of oxygen. e. Aerotolerant Anaerobes: Can tolerate oxygen but do not use it for metabolism. 6. Thioglycolate Media and IdenHfying Oxygen Needs: Thioglycolate media is used to test the oxygen requirements of microorganisms. It contains oxygen and chemicals that combine with dissolved oxygen to create an oxygen gradient within the tube. Bacteria will grow at different levels in the tube, indicaHng their oxygen needs. Obligate anaerobes will grow at the boNom, obligate aerobes at the top, and facultaHve anaerobes throughout the tube. 7. Bacterial Growth Curve: The growth curve in a bacterial culture consists of four phases: - Lag Phase: Bacteria adapt to the environment and do not divide. - ExponenHal (Log) Phase: Rapid growth and division of bacteria.