Review Lect Quiz 1.docx

Review Lecture Quiz 1. Fall 2 Oct. 2024 1. Antoni van Leeuwenhoek was the first person in history to do what? - Antoni van Leeuwenhoek was the first person in history to observe and describe microorganisms using a microscope. - In the late 1600s, he crafted his own microscopes, some of w...

Review Lecture Quiz 1. Fall 2 Oct. 2024 1. Antoni van Leeuwenhoek was the first person in history to do what? - Antoni van Leeuwenhoek was the first person in history to observe and describe microorganisms using a microscope. - In the late 1600s, he crafted his own microscopes, some of which could magnify objects up to 300x, much stronger than the microscopes available at the time. - Through his observations, he was the first to report the existence of bacteria, protozoa, and sperm cells. He called them animalcules (tiny animals). - Leeuwenhoek meticulously described his observations of a wide variety of microbes, including the movement of bacteria and the structure of protozoa. 2. Which common single-celled eukaryotic microbes are generally motile? - Protozoa are the common single-celled eukaryotic microbes that are generally motile. They move through mechanisms such as: - Flagella (e.g., Trypanosoma) - Definition: Flagella are long, whip-like structures that extend from the surface of a cell and are used for movement. They are typically composed of microtubules arranged in a \"9+2\" arrangement (nine pairs of microtubules surrounding a central pair). - Function: Flagella move in a wave-like or whip-like motion that propels the cell forward. The motion is typically unidirectional, but it can be coordinated to create a smooth and efficient mode of locomotion. - Example: - Trypanosoma (causes sleeping sickness) uses a single flagellum to move. - Chlamydomonas (a type of algae) also uses flagella for movement in aquatic environments. - Cilia (e.g., Paramecium) - Definition: Cilia are short, hair-like projections from the surface of some eukaryotic cells. They are also made of microtubules arranged in the \"9+2\" structure, similar to flagella but much shorter in length. Cilia usually cover the entire surface of the cell or are clustered in specific regions. - Function: Cilia beat in a coordinated, rhythmic pattern, often in a back-and-forth motion. This allows the cell to move through fluid or move fluid past the cell (e.g., in the respiratory tract). In protozoa, cilia help propel the organism through water and also facilitate the movement of food toward the cell mouth. - Example: - Paramecium: A ciliated protozoan that uses its cilia to move in a \"swimming\" pattern in aquatic environments. - Pseudopodia (e.g., Amoeba). - These protozoa are typically found in water and soil and can cause diseases (e.g., Plasmodium causes malaria). 3. Which of the following are prokaryotes? - Prokaryotes are organisms that lack a nucleus. They include bacteria and archaea. 4. What are the characteristics of fungi? - Fungi are eukaryotic, non-photosynthetic organisms. They have a cell wall made of chitin and reproduce through spores. Fungi can be unicellular (yeasts) or multicellular (molds). They usually grow in long filaments. 5. The technique developed by Hans Christian Gram. - The Gram stain is a method used to differentiate bacteria into two groups: Gram-positive (purple) and Gram-negative (pink), based on the structure of their cell walls. The difference in staining results is due to variations in the thickness and composition of the bacterial cell wall, with Gram-positive bacteria having a thicker peptidoglycan layer. 6. The action of chemical agents to harm or kill microbes? - Chemical agents disrupt the structure of microbial cells or inhibit their functions, targeting membranes, proteins, or genetic material to kill or inactivate microbes​ 7. What are the characteristics of viruses? - Viruses are acellular, lack cellular structures, and can only reproduce by infecting a host cell. They consist of genetic material (DNA or RNA) surrounded by a protein coat and, in some cases, a lipid envelope 8. What type of pathogen was the first true vaccine used against? - The first true vaccine was used against smallpox, developed by Edward Jenner using cowpox material to immunize against smallpox 9. Inserting a gene from a B virus into yeast is what type of science? - This is an example of recombinant DNA technology, a field in molecular biology where genes from one organism are inserted into another to express desired traits​ 10. In a conventional lab, the first step in identifying bacteria is? - The first step is often Gram staining, which helps differentiate bacteria into Gram-positive and Gram-negative groups based on cell wall structure​ 11. Who is considered the father of chemotherapy? - Paul Ehrlich is considered the father of chemotherapy due to his work on selective toxicity and development of treatments for diseases like syphilis​ 12. Taxonomy is used for? - Taxonomy classifies and names organisms, grouping them based on evolutionary relationships and characteristics​ 13. Who discovered penicillin? - Alexander Fleming discovered penicillin, the first antibiotic, which is produced by the fungus Penicillium notatum 14. Microorganisms devoid of a nucleus are called? - Prokaryotic organisms, including bacteria and archaea, lack a nucleus and membrane-bound organelles 15. What is a hypothesis, popular opinion, a theory? - Hypothesis: A tentative explanation tested through experiments. - Popular opinion: A widely held belief without scientific testing. - Theory: A well-supported explanation of natural phenomena based on a body of evidence 16. Who led the work on fermentation, leading to the discovery of enzymes? - Louis Pasteur studied fermentation and demonstrated that living organisms (yeast) cause fermentation, leading to the understanding of enzymes​ 17. The study of the blood components that fight infection? - This field is known as serology, which studies antibodies and immune responses in blood serum 18. A modern new discipline used in the treatment of infectious diseases. - Modern disciplines like immunology and molecular microbiology are pivotal in treating infectious diseases 19. What are the components of bacterial flagella? - Bacterial flagella consist of a filament, hook, and basal body, and they rotate to propel the bacterium​ 20. Important bacterial cell structures in the formation of biofilms? - Fimbriae and glycocalyces play key roles in biofilm formation by allowing bacteria to adhere to surfaces and each other 21. Slime layer composition in bacteria containing lipids. - Bacterial slime layers typically consist of loosely organized glycocalyx made of polysaccharides, sometimes containing proteins and lipids​ 22. What are the components of bacterial cell walls? - Bacterial cell walls are primarily made of peptidoglycan; Gram-positive bacteria have thick layers, while Gram-negative bacteria have thin layers with an outer membrane containing lipopolysaccharide (LPS) 23. What is Lipid A? - Lipid A is a component of LPS in Gram-negative bacteria, known for its endotoxin properties, which can trigger fever and inflammation 24. Mycoplasma lacks cell walls. How do they survive? - Mycoplasma lack cell walls but survive by having a flexible cell membrane, often living in osmotically balanced environments​ 25. What is osmosis, and how does it work? - Osmosis is the movement of water across a selectively permeable membrane from a region of lower solute concentration to a higher one 26. Osmosis requires a selectively permeable membrane. What are hypotonic, passive, fluid mosaic, hypertonic, and isotonic? - Hypotonic: Lower solute concentration outside, leading water to enter the cell. - Hypertonic: Higher solute concentration outside, causing water to exit the cell. - Isotonic: Equal solute concentration inside and outside, no net water movement. - Passive: Transport without energy input. - Fluid mosaic: Describes the structure of cell membranes​ 27. Functions of the glycocalyx? - Glycocalyces protect against desiccation, help with adherence, and play a role in biofilm formation​ 28. Components of the eukaryotic mitochondria? - Mitochondria have a double membrane, inner folds (cristae), matrix with 70S ribosomes, and DNA similar to prokaryotic DNA 29. What are the endoplasmic reticulum (ER) and its functions? - The ER transports materials within cells, with the rough ER synthesizing proteins and the smooth ER synthesizing lipids​ 30. What is flagella, pseudopodia, cilia, pili, fimbriae. - Flagella: Long, whip-like structures for movement. - Pseudopodia: Temporary cell extensions used by amoeboid cells. - Cilia: Short, hair-like structures for movement or moving substances. - Pili: Structures for DNA transfer between bacterial cells. - Fimbriae: Short, bristle-like projections for adherence​ 31. Compositional characteristics of an acid-fast bacteria. - Acid-fast bacteria, like Mycobacterium, have mycolic acid in their cell walls, making them resistant to desiccation and staining methods 32. Cytoplasmic membrane composition of prokaryotes (bacteria, archaea) and eukaryotes. - Prokaryotes: Phospholipid bilayer with embedded proteins. - Archaea: Have distinct ether-linked lipids. - Eukaryotes: Phospholipid bilayer with embedded proteins and sterols like cholesterol for stability 33. What is endocytosis and exocytosis. - Endocytosis: Process by which cells engulf materials into vesicles. - Exocytosis: Release of materials from cells by vesicle fusion with the cell membrane​ 34. Cholesterol and the cytoplasmic membranes. - Cholesterol helps maintain fluidity in eukaryotic cell membranes​ 35. Cell walls and teichoic acids. - Gram-positive bacterial cell walls contain teichoic acids, which provide structural support and contribute to the cell\'s surface charge 36. Prokaryotic cells and the outer membrane. - The outer membrane in Gram-negative bacteria provides protection and can impede drug entry 37. How to measure viral particles. - Viral particles are typically measured using electron microscopy because they are too small to be resolved with light microscopy. Additionally, techniques like plaque assays can quantify viruses by counting plaque-forming units. 38. Magnifying lenses in the microscope. - Microscopes use objective and ocular lenses to magnify images. A compound microscope has a series of lenses, and the total magnification is the product of the objective and ocular lens magnifications. Oil immersion lenses are used to increase resolution at high magnifications​ 39. Microscopic resolution and the variables impacting it. - Resolution is the ability to distinguish two points as separate. It depends on the wavelength of light and the numerical aperture of the lens. Shorter wavelengths improve resolution, and higher numerical apertures allow for finer detail​ 40. Role of safranin in the Gram stain procedure and how to use it. - Safranin is the counterstain in the Gram stain procedure. It stains Gram-negative bacteria pink/red after decolorization, while Gram-positive bacteria retain the primary stain (crystal violet) and appear purple 41. Why and when to use Carbolfuchsin? - Carbolfuchsin is used in acid-fast staining (e.g., for Mycobacterium species) because it binds to mycolic acids in cell walls, helping identify acid-fast bacteria that resist decolorization by alcohol 42. What is Carbolfuchsin? - Carbolfuchsin is a red, phenolic dye used in the Ziehl-Neelsen acid-fast stain to identify acid-fast bacteria. It binds strongly to lipid-rich cell walls. 43. Recognizing microbial and blood-stained microscope smears after using the various staining techniques. - After Gram staining, Gram-positive bacteria appear purple, while Gram-negative bacteria are pink. Acid-fast bacteria appear red with a blue background in acid-fast stains. Blood-stained smears often use Wright or Giemsa stains to highlight different cell types 44. Variables used to place an organism into a classification domain? - Organisms are classified into domains (Bacteria, Archaea, Eukarya) based on ribosomal RNA sequences, cell structure, metabolic properties, and genetic material 45. Rapid confirmation tests for members of the Salmonella species. - Rapid confirmation of Salmonella involves biochemical tests, like the API 20E, and serological tests, which detect specific antigens associated with Salmonella​ 46. Role of ribosomal RNA as the basis for defining bacterial species? - Ribosomal RNA sequences are highly conserved, making them ideal for distinguishing between bacterial species and establishing evolutionary relationships​ 47. How does the Gram stain work? - The Gram stain differentiates bacteria by cell wall structure. Crystal violet stains all cells, iodine fixes the dye, and an ethanol-acetone wash decolorizes Gram-negative cells, which are then counterstained with safranin to appear pink, while Gram-positive cells remain purple 48. Science that provides the name of organisms? - Taxonomy is the science of classifying and naming organisms, including classification, nomenclature, and identification 49. The function of a chemical mordant in staining. - A mordant, like iodine in Gram staining, binds to the primary stain and enhances its retention in the cell, making the staining process more effective​ 50. Differences and advantages of various types of microscopes in the observation of biological specimens. - Light microscopes (bright-field, dark-field, phase-contrast) are good for live or stained specimens. Electron microscopes (TEM and SEM) provide much higher magnification and resolution, allowing observation of ultrastructure. Fluorescence and confocal microscopes use fluorescent dyes for detailed views​ 51. Role of ethanol-acetone in the Gram staining. - Ethanol-acetone acts as a decolorizer in the Gram stain. It dissolves the outer membrane of Gram-negative bacteria, allowing the crystal violet-iodine complex to be washed out, while Gram-positive cells retain the complex​ 52. What are acidic dyes, and how they are used? - Acidic dyes, which are negatively charged, are repelled by bacterial cells (often negatively charged) and typically stain the background, creating a negative stain effect. These dyes are useful for observing cell shape and structure without directly staining the cells​ 53. What's the target of Methylene blue as a stain? - Methylene blue, a basic dye, stains acidic structures like DNA in the cell, helping to visualize cell shape, size, and arrangement in a simple stain procedure​ 54. What is cellular metabolism? - Metabolism is the total of all biochemical reactions within a cell, including catabolic pathways (breaking down molecules to release energy) and anabolic pathways (using energy to build complex molecules) 55. What are anabolism and anabolic pathways? - Anabolism involves reactions that build larger molecules from smaller ones, requiring energy. These pathways are critical for cell growth, repair, and storage of energy 56. What is an enzyme, its components, and its target? - Enzymes are biological catalysts that speed up chemical reactions without being consumed. They are made up of proteins, sometimes with cofactors or coenzymes, and they target specific substrates to facilitate reactions​ 57. What is Sulfanilamide, and how does it work? - Sulfanilamide is an antimicrobial drug that inhibits bacterial growth by mimicking PABA (para-aminobenzoic acid) and blocking folic acid synthesis, which bacteria need to grow and replicate 58. What are vitamins and their relationship with enzymes? - Vitamins often serve as coenzymes or precursors to coenzymes, assisting enzymes in catalyzing biochemical reactions by binding to them and enabling their activity​ 59. Pyruvic acid is a product of what? - Pyruvic acid is produced from glucose during glycolysis, the first step in carbohydrate catabolism 60. What is an anaerobe, and how it differs from aerobic bacteria? - Anaerobes grow without oxygen and may even be harmed by it, whereas aerobic bacteria require oxygen for their metabolic processes​ 61. What is the electron transport chain and its function? - The electron transport chain (ETC) is a series of proteins in the membrane that transfer electrons to create a proton gradient. This gradient powers ATP synthesis, producing energy for the cell​ 62. What is catabolism and the by-products when the target is a protein? - Catabolism breaks down molecules to release energy. When proteins are catabolized, they produce amino acids, which are further broken down into ammonia, urea, and other nitrogenous waste products​ 63. What is chemiosmosis, and how does it operate in the light-dependent reactions of photosynthesis? - Chemiosmosis uses a proton gradient across a membrane to produce ATP. In photosynthesis, light energy creates a proton gradient that drives ATP synthesis during the light-dependent reaction 64. What is fermentation, and which fermentation products are useful in manufacturing cheese and bread? - Fermentation is a metabolic process that converts sugars to acids, gases, or alcohol in the absence of oxygen. Lactic acid (for cheese) and carbon dioxide (for bread) are useful fermentation products 65. Using metabolic pathways to identify bacteria. - Bacteria are identified by their metabolic pathways through biochemical tests, which can detect specific enzyme activities, fermentation products, and nutrient utilization​ 66. Relationship between photophosphorylation and glucose synthesis. - Photophosphorylation in photosynthesis generates ATP and NADPH, which fuel the Calvin cycle to synthesize glucose from CO₂​ 67. Relationship between fermentation and oxygen availability - Fermentation occurs when oxygen is unavailable, allowing cells to produce ATP anaerobically. It regenerates NAD+ for glycolysis by using organic molecules as the final electron acceptors​ 68. Where is the majority of ATP generated in prokaryotic cells? - Most ATP in prokaryotes is generated at the cell membrane in the electron transport chain through oxidative phosphorylation 69. Function of oxidoreductases as an electron donor. - Oxidoreductases are enzymes that facilitate redox reactions, transferring electrons from donor molecules (like NADH) to acceptors, often in energy production pathways​ 70. Be able to identify glycolysis, Krebs cycle, fermentation, and electron transport chain. - Glycolysis: glucose breakdown into pyruvate with ATP production. - Krebs cycle: produces ATP, NADH, and FADH₂ from acetyl-CoA. - Fermentation: anaerobic conversion of pyruvate to regenerate NAD+. - Electron Transport Chain: produces a large amount of ATP using redox reactions 71. what are essential amino acids? - Essential amino acids cannot be synthesized by the body and must be obtained from the diet; they are required for protein synthesis​ 72. What's the difference between aerotolerant, anaerobic, obligate aerobe, and facultative anaerobe? - Obligate aerobes need oxygen. Obligate anaerobes are harmed by oxygen. Facultative anaerobes can survive with or without oxygen, while aerotolerant anaerobes do not use oxygen but tolerate it 73. What are carotenoid pigments in phototrophs and their function? - Carotenoids in phototrophs absorb light for photosynthesis and protect cells from oxidative damage caused by light​ 74. What are thioglycolate media and its function? What is a microaerophile, aerotolerant anaerobe, obligate anaerobe, obligate aerobe? - Thioglycolate media is used to test oxygen requirements of microbes. It creates an oxygen gradient, allowing differentiation among aerobic, anaerobic, facultative, and microaerophilic organisms 75. Effect of higher than maximum growth temperature on an organism. - Higher than optimal temperatures can denature proteins, disrupt membrane integrity, and ultimately kill the organism 76. In a brine food environment, which organisms are likely to contaminate? - Halophiles, organisms that thrive in high-salt conditions, are likely to contaminate brine environments 77. Organisms that can grow with or without oxygen. - Facultative anaerobes can grow with or without oxygen, using aerobic respiration when available and switching to anaerobic pathways otherwise​ 78. What is a fastidious organism where it can be grown? - Fastidious organisms have complex nutritional requirements and are grown on enriched media that provide essential growth factors​ 79. What are MacConkey agar, its characteristics, and applications? - MacConkey agar is a selective and differential medium that inhibits Gram-positive bacteria and differentiates lactose fermenters (pink colonies) from non-fermenters (colorless) among Gram-negative bacteria 80. Indirect method for estimating the number of microbes in a sample? - Indirect methods include measuring turbidity with a spectrophotometer, as more turbidity indicates a higher microbial count 81. Using salt and sugar in food preservation. - Salt and sugar create hypertonic environments, causing water to leave microbial cells through osmosis, which inhibits microbial growth by dehydration​ 82. What is an isolate, a colony, an aggregate, a biofilm, media - Isolate: a single strain of a microorganism separated from a sample. - Colony: a visible cluster of microbes originating from a single progenitor cell. - Aggregate: a collection of cells grouped together, not necessarily from one progenitor. - Biofilm: a complex community of microbes adhering to a surface, often encased in a protective matrix. - Media: substances used to support microbial growth in the lab, which can be solid, semi-solid, or liquid 83. How to estimate the number of CFUs (colony-forming units)? - CFUs are estimated using methods like serial dilution and plate counts, where colonies are counted on agar plates after incubation and multiplied by the dilution factor 84. What is Blood agar and its application? - Blood agar is an enriched, differential medium containing sheep blood that supports the growth of many organisms and differentiates them based on hemolytic activity (alpha, beta, gamma hemolysis 85. Recognize the various stages of bacterial growth. - The bacterial growth curve includes: - Lag phase: adaptation period with no cell division. - Log (exponential) phase: rapid cell division. - Stationary phase: nutrient depletion slows growth; death equals growth rate. - Death phase: cell death exceeds new growth due to lack of nutrients​ 86. What is bacterial generation time? - Generation time is the time required for a bacterial population to double in number, depending on environmental conditions and the species​ 87. What are Microaerophiles, and where do they grow best? - Microaerophiles require low oxygen levels (less than atmospheric levels) and grow best in environments with reduced oxygen concentrations​ 88. Calculate the number of bacteria using the dilution method, given an inoculum with a known number of cells, the generation time, and incubation conditions. - To calculate bacterial population: - Use the formula: - N = N0 x 2 \^ (t/g) - N0 is the initial number of cells - T is the incubation time - G is the generation time - Apply this after determining the dilution factor and colony counts from plate counting techniques 89. What are complex communities of microbes that adhere to surfaces? - Complex communities of microbes that adhere to surfaces are called biofilms. They form through quorum sensing, where microbes communicate and coordinate, often becoming more resistant to antibiotics​