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Questions and Answers

What is the goal of sterilization in microbiology?

The goal of sterilization in microbiology is to remove all microorganisms, making an item absolutely free of microbes, endospores, and viruses.

Define pasteurization.

Pasteurization is a brief heat treatment used to reduce organisms causing food spoilage and to protect heat-sensitive products.

Which of the following are the two main categories of microbial control methods? (Select all that apply)

  • Biological methods
  • Chemical methods (correct)
  • Physical methods (correct)
  • Mechanical methods

What does the term "bacteriostatic" refer to?

<p>Bacteriostatic refers to inhibiting, but not killing, microbes.</p> Signup and view all the answers

Explain the Decimal Reduction Time (D-value).

<p>D-value is the time required to kill 90% of a microbial population at a specific temperature.</p> Signup and view all the answers

Which of the following factors affect the effectiveness of antimicrobial treatment? (Select all that apply)

<p>Number of microbes (A), Environment (B), Time of exposure (C), Microbial characteristics (D)</p> Signup and view all the answers

What is the difference between disinfection and antisepsis?

<p>Disinfection removes pathogens from inanimate objects, while antisepsis removes pathogens from living tissues.</p> Signup and view all the answers

How do bile salts in MacConkey agar function?

<p>They inhibit the growth of Gram-positive bacteria, making it selective for Gram-negative organisms.</p> Signup and view all the answers

What does it mean for a medium to be both selective and differential?

<p>Such a medium inhibits certain microorganisms while allowing others to grow and differentiates between them based on specific biochemical reactions.</p> Signup and view all the answers

What is the main purpose of using Mannitol Salt Agar?

<p>It is used for isolating osmotolerant bacteria and differentiating those that ferment mannitol.</p> Signup and view all the answers

What is the difference between sterilization and sanitization?

<p>Sterilization removes all microbial life, while sanitization reduces microbial counts to safe levels on surfaces and utensils.</p> Signup and view all the answers

Define commercial sterilization.

<p>Commercial sterilization specifically targets the destruction of Clostridium botulinum endospores in canned goods.</p> Signup and view all the answers

What is the purpose of filtration in microbial control?

<p>Filtration physically removes microorganisms from air or liquids.</p> Signup and view all the answers

What does "logarithmic death rate" refer to in microbial control?

<p>It describes how a fixed proportion of microbial cells die per unit of time during treatment.</p> Signup and view all the answers

Explain the purpose of using blood agar as a differential medium.

<p>Blood agar helps identify bacteria based on their hemolytic activity.</p> Signup and view all the answers

What is the role of pH indicators in differential media?

<p>pH indicators detect metabolic byproducts, such as acid production, and change color accordingly.</p> Signup and view all the answers

What makes MacConkey agar differential?

<p>Its lactose and pH indicator allow differentiation between lactose-fermenting and non-fermenting bacteria.</p> Signup and view all the answers

Which of the following are examples of sterilization techniques?

<p>Heat sterilization (autoclaving) (A), Chemical sterilization (ethylene oxide gas) (D)</p> Signup and view all the answers

What is the main limitation of pasteurization?

<p>It does not achieve sterilization but only reduces the number of pathogens and spoilage organisms.</p> Signup and view all the answers

How does irradiation control microbial growth?

<p>Irradiation damages microbial DNA, preventing replication and survival.</p> Signup and view all the answers

What is the purpose of using Thayer-Martin agar?

<p>It is a selective medium used to isolate Neisseria gonorrhoeae by inhibiting contaminating organisms.</p> Signup and view all the answers

How does heat sterilization work?

<p>Heat sterilization kills microorganisms by denaturing their proteins and disrupting their membranes.</p> Signup and view all the answers

What is the difference between disinfectants and antiseptics?

<p>Disinfectants are used on inanimate surfaces, while antiseptics are used on living tissues.</p> Signup and view all the answers

What are biofilms, and how do they affect microbial control?

<p>Biofilms are structured microbial communities attached to surfaces, often making microbes more resistant to control methods.</p> Signup and view all the answers

Why is high-temperature short-time (HTST) pasteurization preferred for milk?

<p>HTST effectively kills pathogens while preserving milk's nutritional and sensory qualities.</p> Signup and view all the answers

What is a biocide, and how is it different from a bacteriostatic agent?

<p>A biocide kills microorganisms, whereas a bacteriostatic agent inhibits their growth without killing them.</p> Signup and view all the answers

What is the significance of a medium being chemically defined?

<p>A chemically defined medium has a known, precise chemical composition, allowing for controlled experimental conditions.</p> Signup and view all the answers

How does mechanical filtration remove microorganisms?

<p>It physically traps microorganisms within the pores of a filter, effectively removing them from liquids or air.</p> Signup and view all the answers

What is the principle behind using ultraviolet (UV) light for microbial control?

<p>UV light damages microbial DNA, preventing replication and leading to cell death.</p> Signup and view all the answers

Why is the presence of organic matter significant during disinfection?

<p>Organic matter can shield microbes from disinfectants, reducing their effectiveness.</p> Signup and view all the answers

Application: How would you design a sterilization protocol for a hospital operating room to ensure no pathogens survive?

<p>Use a combination of autoclaving surgical tools, UV light for surface disinfection, and chemical sterilants for heat-sensitive equipment.</p> Signup and view all the answers

Analysis: Why might UV sterilization be less effective in hospital rooms with heavy organic matter present?

<p>Organic matter can block UV light, preventing it from reaching microorganisms effectively.</p> Signup and view all the answers

Evaluation: Evaluate the effectiveness of using moist heat sterilization compared to chemical disinfectants for cleaning reusable medical devices.

<p>Moist heat is more reliable for killing all microbes, including spores, but may damage heat-sensitive devices, where chemical disinfectants would be better suited.</p> Signup and view all the answers

Application: How would you use selective media to identify a bacterial contaminant in a food production facility?

<p>Use MacConkey agar to differentiate lactose-fermenting Gram-negative bacteria from other contaminants.</p> Signup and view all the answers

Synthesis: Propose a combination of sterilization techniques to handle biofilm-contaminated surfaces in water pipelines.

<p>Combine chemical disinfectants like chlorine with mechanical removal methods (scrubbing or ultrasonic cleaning) to disrupt biofilms.</p> Signup and view all the answers

Analysis: Why does high-temperature short-time (HTST) pasteurization work well for milk but not for thicker liquids like cream?

<p>The higher viscosity of cream reduces heat penetration, requiring longer treatment times.</p> Signup and view all the answers

Evaluation: Assess the risks and benefits of using ethylene oxide gas for sterilizing surgical tools in remote areas.

<p>Benefits include sterilization of heat-sensitive tools, but risks involve toxicity, flammability, and requiring special equipment.</p> Signup and view all the answers

Application: How could you use D-value calculations to decide on sterilization times for canned foods?

<p>Calculate the time needed to achieve a specific microbial reduction at a given temperature to ensure safety while preserving food quality.</p> Signup and view all the answers

Synthesis: Design an effective sanitation plan for a food processing plant using principles of microbial control.

<p>Include daily cleaning with chemical disinfectants, weekly heat sterilization of machinery, and regular microbial testing.</p> Signup and view all the answers

Analysis: Why might bacterial populations in biofilms survive disinfection treatments that kill free-floating cells?

<p>Biofilms provide a physical barrier and a supportive environment, reducing disinfectant penetration and effectiveness.</p> Signup and view all the answers

Evaluation: Compare the effectiveness of sterilization using autoclaving versus gamma irradiation for pharmaceutical products.

<p>Autoclaving is cost-effective and widely used but unsuitable for heat-sensitive materials, while gamma irradiation is better for packaged and heat-sensitive items.</p> Signup and view all the answers

Synthesis: Develop a protocol for ensuring sterilized surgical instruments remain sterile during transport.

<p>Use sterile packaging and seal them in airtight containers to prevent microbial contamination.</p> Signup and view all the answers

Application: How could you use blood agar to diagnose bacterial throat infections?

<p>Observe hemolysis patterns to identify pathogens like Streptococcus pyogenes based on their ability to lyse red blood cells.</p> Signup and view all the answers

Analysis: Why might pasteurization not kill all pathogens in non-liquid foods?

<p>Solid or dense foods can prevent uniform heat penetration, leaving some microbes unaffected.</p> Signup and view all the answers

Evaluation: Critique the use of chemical disinfectants in households compared to heat sterilization.

<p>Disinfectants are practical and easy to use but less reliable than heat sterilization for complete microbial elimination.</p> Signup and view all the answers

Synthesis: How would you create a sterilization plan for reusable water bottles in a gym?

<p>Use a combination of chemical disinfectants and UV sterilization, ensuring no residues remain on bottles.</p> Signup and view all the answers

Application: How can the principles of microbial control be applied to reduce antibiotic-resistant bacteria in hospitals?

<p>Use strict sterilization protocols, limit antibiotic use, and monitor for resistant strains regularly.</p> Signup and view all the answers

Analysis: Why might organic matter on surgical instruments reduce the effectiveness of autoclaving?

<p>Organic residues can insulate microbes from heat and prevent complete sterilization.</p> Signup and view all the answers

Evaluation: Compare the use of UV light versus ozone for disinfecting public swimming pools.

<p>UV light leaves no chemical residue but doesn't provide residual protection like ozone does.</p> Signup and view all the answers

Synthesis: Propose an emergency sterilization plan for contaminated medical equipment in disaster zones.

<p>Use portable autoclaves or chemical sterilants for heat-sensitive equipment and prioritize single-use sterile items when possible.</p> Signup and view all the answers

What are the two main categories of microbial control methods?

<p>Physical methods (e.g., heat, irradiation, filtration) and chemical methods (e.g., antimicrobial chemicals) (D)</p> Signup and view all the answers

What does the term “bacteriostatic” refer to?

<p>Bacteriostatic refers to inhibiting, but not killing, microbes.</p> Signup and view all the answers

What factors affect the effectiveness of antimicrobial treatment?

<p>The number of microbes, environment (organic matter, temperature, biofilms), time of exposure, and microbial characteristics (A)</p> Signup and view all the answers

What does “logarithmic death rate” refer to in microbial control?

<p>It describes how a fixed proportion of microbial cells die per unit of time during treatment.</p> Signup and view all the answers

Name two examples of sterilization techniques.

<p>Heat sterilization (autoclaving) and chemical sterilization (ethylene oxide gas) (B)</p> Signup and view all the answers

How would you design a sterilization protocol for a hospital operating room to ensure no pathogens survive?

<p>Use a combination of autoclaving surgical tools, UV light for surface disinfection, and chemical sterilants for heat-sensitive equipment. (A)</p> Signup and view all the answers

Why might UV sterilization be less effective in hospital rooms with heavy organic matter present?

<p>Organic matter can block UV light, preventing it from reaching microorganisms effectively.</p> Signup and view all the answers

Evaluate the effectiveness of using moist heat sterilization compared to chemical disinfectants for cleaning reusable medical devices.

<p>Moist heat is more reliable for killing all microbes, including spores, but may damage heat-sensitive devices, where chemical disinfectants would be better suited. (C)</p> Signup and view all the answers

How would you use selective media to identify a bacterial contaminant in a food production facility?

<p>Use MacConkey agar to differentiate lactose-fermenting Gram-negative bacteria from other contaminants.</p> Signup and view all the answers

Propose a combination of sterilization techniques to handle biofilm-contaminated surfaces in water pipelines.

<p>Combine chemical disinfectants like chlorine with mechanical removal methods (scrubbing or ultrasonic cleaning) to disrupt biofilms.</p> Signup and view all the answers

Why does high-temperature short-time (HTST) pasteurization work well for milk but not for thicker liquids like cream?

<p>The higher viscosity of cream reduces heat penetration, requiring longer treatment times.</p> Signup and view all the answers

Assess the risks and benefits of using ethylene oxide gas for sterilizing surgical tools in remote areas.

<p>Benefits include sterilization of heat-sensitive tools, but risks involve toxicity, flammability, and requiring special equipment. (D)</p> Signup and view all the answers

How could you use D-value calculations to decide on sterilization times for canned foods?

<p>Calculate the time needed to achieve a specific microbial reduction at a given temperature to ensure safety while preserving food quality.</p> Signup and view all the answers

Design an effective sanitation plan for a food processing plant using principles of microbial control.

<p>Include daily cleaning with chemical disinfectants, weekly heat sterilization of machinery, and regular microbial testing.</p> Signup and view all the answers

Why might bacterial populations in biofilms survive disinfection treatments that kill free-floating cells?

<p>Biofilms provide a physical barrier and a supportive environment, reducing disinfectant penetration and effectiveness.</p> Signup and view all the answers

Compare the effectiveness of sterilization using autoclaving versus gamma irradiation for pharmaceutical products.

<p>Autoclaving is cost-effective and widely used but unsuitable for heat-sensitive materials, while gamma irradiation is better for packaged and heat-sensitive items. (A)</p> Signup and view all the answers

Develop a protocol for ensuring sterilized surgical instruments remain sterile during transport.

<p>Use sterile packaging and seal them in airtight containers to prevent microbial contamination.</p> Signup and view all the answers

How could you use blood agar to diagnose bacterial throat infections?

<p>Observe hemolysis patterns to identify pathogens like Streptococcus pyogenes based on their ability to lyse red blood cells.</p> Signup and view all the answers

Why might pasteurization not kill all pathogens in non-liquid foods?

<p>Solid or dense foods can prevent uniform heat penetration, leaving some microbes unaffected.</p> Signup and view all the answers

Critique the use of chemical disinfectants in households compared to heat sterilization.

<p>Disinfectants are practical and easy to use but less reliable than heat sterilization for complete microbial elimination. (A)</p> Signup and view all the answers

How would you create a sterilization plan for reusable water bottles in a gym?

<p>Use a combination of chemical disinfectants and UV sterilization, ensuring no residues remain on bottles.</p> Signup and view all the answers

How can the principles of microbial control be applied to reduce antibiotic-resistant bacteria in hospitals?

<p>Use strict sterilization protocols, limit antibiotic use, and monitor for resistant strains regularly.</p> Signup and view all the answers

Why might organic matter on surgical instruments reduce the effectiveness of autoclaving?

<p>Organic residues can insulate microbes from heat and prevent complete sterilization. (B)</p> Signup and view all the answers

Compare the use of UV light versus ozone for disinfecting public swimming pools.

<p>UV light leaves no chemical residue but doesn't provide residual protection like ozone does. (A)</p> Signup and view all the answers

Propose an emergency sterilization plan for contaminated medical equipment in disaster zones.

<p>Use portable autoclaves or chemical sterilants for heat-sensitive equipment and prioritize single-use sterile items when possible.</p> Signup and view all the answers

What is the difference between a virus and a bacteriophage?

<p>A virus can infect any type of cell, including bacteria, while a bacteriophage is a type of virus that specifically infects bacteria.</p> Signup and view all the answers

What is the role of the lysogenic cycle in some viruses?

<p>The lysogenic cycle allows the viral DNA to integrate into the host cell's genome, becoming a prophage. This allows the virus to replicate along with the host DNA.</p> Signup and view all the answers

Explain what a "genetic switch" is in the lysogenic/lytic cycle of bacteriophages.

<p>A genetic switch determines whether a temperate phage will follow the lytic or lysogenic lifecycle. This decision depends on factors like the host's health and environmental stimuli.</p> Signup and view all the answers

Match the following terms with their definitions.

<p>Attachment = The phage attaches to the bacterial cell through tail fibers. Penetration = The bacteriophage injects its DNA into the host cell using lysozyme. Maturation = The phage's DNA is incorporated and replicated within the host cell. Biosynthesis = New phage particles are assembled inside the host cell. Release = The phage lysozyme degrades the bacterial cell wall, releasing the newly formed bacteriophages.</p> Signup and view all the answers

Match the following terms related to animal virus multiplication with their definitions.

<p>Attachment = Attachment of viruses to the cell membrane, often through a specific receptor. Penetration = Entry of the virus into the host cell through endocytosis or fusion. Uncoating = Removal of the viral capsid, releasing the viral genome into the cytoplasm. Biosynthesis = Replication of viral nucleic acid (DNA or RNA) and synthesis of viral proteins using host cell machinery. Maturation = Assembly of viral nucleic acid and proteins into new viral particles. Release = Release of newly formed viral particles from the host cell, usually through budding or lysis.</p> Signup and view all the answers

What are the key differences between the life cycle of a bacteriophage and an animal virus?

<p>Bacteriophages typically inject only their DNA into the host cell, while animal viruses generally enter the host cell as a whole. Bacteriophages often cause lysis of the host cell during release, while animal viruses may use budding for release.</p> Signup and view all the answers

How does the lytic cycle impact the host cell?

<p>The lytic cycle results in the destruction of the host cell. The virus replicates and produces new viral particles, leading to the lysis of the host cell, releasing the new viruses.</p> Signup and view all the answers

What are the key characteristics of the lysogenic cycle?

<p>The lysogenic cycle allows for the viral DNA to integrate into the host cell's DNA and replicate along with it. The viral genes are typically repressed, allowing the virus to coexist with the host cell.</p> Signup and view all the answers

The lambda repressor is a crucial factor in determining whether the lysogenic or lytic cycle occurs for a bacteriophage.

<p>True (A)</p> Signup and view all the answers

What is the process of integration in the lysogenic cycle of bacteriophages?

<p>Integration involves the incorporation of the phage's DNA into the host cell's genome. This occurs through a specific recombination process involving the phage's attachment site (attP) and the host's attachment site (attB).</p> Signup and view all the answers

Describe the process of transduction in bacteria.

<p>Transduction is a method of horizontal gene transfer in bacteria, mediated by bacteriophages. It occurs when a bacteriophage carries bacterial DNA from one host cell to another.</p> Signup and view all the answers

Explain the difference between general transduction and specialized transduction.

<p>General transduction involves accidental packaging of bacterial DNA fragments into a phage. Specialized transduction occurs when a phage excises itself from the host chromosome carrying a segment of the host DNA, often a specific gene.</p> Signup and view all the answers

Transduction is a crucial process that allows bacteria to acquire new genes, contributing to their evolution and adaptability.

<p>True (A)</p> Signup and view all the answers

Explain what a sigma factor and a Kozack sequence are in an example of transduction.

<p>The sigma factor is a protein that helps RNA polymerase recognize and bind to promoter regions, while the Kozack sequence is a specific sequence in mRNA essential for the initiation of protein synthesis.</p> Signup and view all the answers

The process of transduction can be used to transfer useful genes to bacteria, offering a potential tool for gene therapy and biotechnology.

<p>True (A)</p> Signup and view all the answers

What are the key steps involved in the multiplication cycle of animal viruses?

<p>The key steps include attachment, penetration, uncoating, biosynthesis, maturation, and release. Viruses bind to the host cell, enter through endocytosis or fusion, release their genetic material, replicate using host cell machinery, assemble new viral particles, and then exit the host cell.</p> Signup and view all the answers

What is the key difference in the way animal viruses and bacteriophages enter host cells?

<p>Animal viruses often use endocytosis or membrane fusion, while bacteriophages can penetrate directly through the cell wall.</p> Signup and view all the answers

Animal viruses can bud from the host cell, acquiring an envelope, while bacteriophages generally cause lysis of the host cell.

<p>True (A)</p> Signup and view all the answers

Flashcards

Tryptophan Operon

A group of genes in bacteria that regulate tryptophan synthesis.

Lactose Operon

A group of genes in bacteria that are regulated to produce enzymes for lactose metabolism.

Promoter

DNA region where RNA polymerase binds to start transcription.

Operator

DNA region where a repressor protein binds, blocking transcription.

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Lac Repressor (LacI)

Protein that blocks transcription of the lac operon when lactose is absent.

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CAP (Catabolite Activator Protein)

Protein that enhances lac operon transcription when glucose is scarce.

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cAMP

Cyclic AMP; molecule that activates CAP when glucose is low.

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Inducible Operon

Operon that is turned on in the presence of a specific inducer.

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Repressible Operon

Operon that is turned off in the presence of a specific repressor.

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Negative Feedback

Regulation where the product of a process inhibits its own production.

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Lysogenic Cycle

Bacteriophage remains dormant by integrating its DNA into host DNA.

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Lytic Cycle

Bacteriophage replicates and lyses the host cell.

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Prophage

Phage DNA integrated into the bacterial chromosome.

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Bacteriophage

Virus that infects bacteria.

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Transduction

Transfer of bacterial DNA from one bacterium to another by a bacteriophage.

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General Transduction

Random transfer of bacterial DNA during the lytic cycle.

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Specialized Transduction

Transfer of specific bacterial genes during lysogenic cycle excision.

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Reverse Transcriptase

Enzyme that converts RNA into DNA in retroviruses.

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Provirus

Viral DNA integrated into host DNA in retroviruses.

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What is the main goal of sterilization?

To completely eliminate all microorganisms, including endospores and viruses, from an object or environment.

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What is pasteurization?

A milder heat treatment that kills pathogens and reduces spoilage organisms, but does not sterilize.

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How does a bacteriostatic agent work?

It inhibits microbial growth without killing the microorganisms.

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What is the D-value?

The time required to kill 90% of a microbial population at a specific temperature.

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What factors impact how well an antimicrobial treatment works?

Number of microbes, environmental conditions (like temperature and organic matter), time of exposure, and microbial characteristics.

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What's the difference between disinfection and antisepsis?

Disinfection removes pathogens from inanimate objects, while antisepsis removes pathogens from living tissues.

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What is the purpose of bile salts in MacConkey agar?

They inhibit the growth of Gram-positive bacteria, making it a selective medium for Gram-negative organisms.

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What does it mean for a medium to be both selective and differential?

It inhibits the growth of certain microorganisms while allowing others to grow and differentiates them by their distinct reactions.

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Why do we use Mannitol Salt Agar?

To select for osmotolerant bacteria and differentiate those that ferment mannitol.

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What is the difference between sterilization and sanitization?

Sterilization eliminates all microbial life, while sanitization reduces microbes to safe levels.

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What is commercial sterilization?

A heat treatment specifically targeting Clostridium botulinum endospores in canned goods.

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How does filtration work in antimicrobial control?

It physically removes microorganisms from liquids or air by trapping them in a filter.

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What does 'logarithmic death rate' mean?

During treatment, a consistent proportion of microbes are killed per unit of time, like halving the population every minute.

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Why is blood agar a differential medium?

It helps identify bacteria based on their hemolytic activity, or ability to lyse red blood cells.

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What is the role of pH indicators in differential media?

They detect specific metabolic byproducts, often acid production, and change color accordingly.

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What makes MacConkey agar differential?

It contains lactose and a pH indicator, which allows differentiation based on lactose fermentation.

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What are two examples of sterilization techniques?

Autoclaving (moist heat under pressure) and chemical sterilization with ethylene oxide gas are common examples.

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What is the main limitation of pasteurization?

It does not achieve complete sterilization; it only reduces the number of pathogens and spoilage organisms.

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How does irradiation control microbial growth?

It damages microbial DNA, preventing replication and survival.

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What is a biocide, and how is it different from a bacteriostatic agent?

A biocide kills microorganisms, while a bacteriostatic agent only inhibits their growth.

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Why is a medium considered chemically defined?

It has a known and precisely controlled chemical composition, making it ideal for experimental accuracy.

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How does mechanical filtration remove microorganisms?

It physically traps microorganisms within the filter pores, preventing them from passing through.

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What is the principle behind UV light for microbial control?

UV light damages microbial DNA, leading to cell death and preventing replication.

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Why is the presence of organic matter significant during disinfection?

Organic matter can shield microbes from disinfectants, reducing their effectiveness.

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Why might UV sterilization be less effective in a hospital room with lots of organic matter?

Organic matter can block UV light from reaching the microorganisms, making it less effective.

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How does HTST pasteurization work well for milk but not for thicker liquids like cream?

The higher viscosity of thicker liquids like cream reduces heat penetration, requiring longer treatment times for effectiveness.

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What are biofilms, and how do they affect microbial control?

Biofilms are structured microbial communities attached to surfaces, making microbes more resistant to control methods.

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Why might bacterial populations in biofilms survive disinfection treatments?

Biofilms provide a physical barrier and a supportive environment, reducing disinfectant penetration and effectiveness.

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What are capsid proteins?

Proteins that form the protective outer shell of a virus, protecting the genetic material within.

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How does attachment differ between bacteriophages and animal viruses?

Bacteriophages attach to specific receptors on the bacterial cell surface, while animal viruses attach to receptors on the host cell membrane.

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What is the role of the lambda repressor protein in phage infection?

It determines whether the phage will enter the lytic or lysogenic cycle, regulating the expression of genes for each pathway.

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What is the difference between the lysogenic and lytic cycles for temperate phages?

Lysogenic cycle: Phage DNA integrates into host DNA, remaining dormant. Lytic cycle: Phage replicates and lyses the host cell.

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Explain what happens during the lytic phase of a temperate phage infection.

The phage takes over the host's machinery to replicate its viral components, eventually leading to host cell lysis and release of new phages.

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How does generalized transduction differ from specialized transduction?

Generalized transduction: Random transfer of bacterial DNA during a lytic cycle. Specialized transduction: Transfer of specific bacterial genes during lysogenic cycle excision.

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What is the main difference between the life cycle of a DNA virus and an RNA virus?

DNA viruses replicate their DNA in the host cell's nucleus, while RNA viruses replicate their RNA in the cytoplasm.

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What is unique about the life cycle of retroviruses?

They use reverse transcriptase to convert their RNA genome into DNA, which then integrates into the host cell's genome.

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What is a provirus?

Viral DNA that has been integrated into the host cell's genome, allowing for persistent infection.

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Susceptibility

The lack of resistance to a disease, meaning the host is likely to get sick.

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Resistance

The ability to ward off a disease, meaning the host is likely to stay healthy.

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Nonspecific Resistance

General defenses that act against any pathogen. They don't target specific invaders.

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Specific Resistance

Immunity, which is resistance to a specific pathogen. It's like a targeted defense.

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Pathogenicity

The ability of a microbe to cause disease; how good it is at making you sick.

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Innate Immunity

The body's first line of defense, present from birth. It's nonspecific and acts quickly.

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Adaptive Immunity

Specific immunity, developed over time. It's targeted and has memory.

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Physical Barriers

The first line of defense, like skin and mucous membranes, preventing microbes from entering.

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Mucous Membranes

Linings of organs like the digestive and respiratory tracts, trapping and removing microbes.

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Ciliary Escalator

Hair-like structures in the respiratory tract that move mucus, clearing microbes

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Normal Microbiota

Beneficial microbes living on and in your body. They protect you from disease.

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Microbial Antagonism

Competition between microbes, where good bacteria outcompete harmful ones.

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Transient Microbiota

Microbes that temporarily live on your body, usually for a short time.

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Symbiosis

The relationship between normal microbiota and the host. It can be beneficial or harmful.

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Commensalism

One organism benefits, while the other is unaffected.

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Mutualism

Both organisms benefit from the relationship.

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Parasitism

One organism benefits at the expense of the other.

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Opportunistic Pathogen

A microbe that only causes disease when the body's defenses are weakened.

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Infection

When pathogenic microbes enter the body and multiply, causing a disruption.

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Disease

Any deviation from normal health, often caused by microbes or their products.

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Inflammation

The body's response to injury or infection, characterized by redness, swelling, heat and pain.

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Complement System

A group of proteins in the blood that work together to destroy microbes.

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Opsonization

A process where antibodies or complement proteins coat microbes, making them easier for phagocytes to engulf.

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Membrane Attack Complex (MAC)

A group of complement proteins that form pores in microbial membranes, leading to lysis.

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Phagocytes

White blood cells that engulf and destroy microbes.

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Antigen

A molecule that triggers an immune response, usually a protein or carbohydrate.

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Antigen Presenting Cells (APCs)

Cells that digest microbes and present antigens to T cells, initiating an immune response.

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MHC Molecules

Major histocompatibility complex molecules. They present antigens to T cells.

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Helper T Cells (TH)

T cells that activate other immune cells, like B cells and cytotoxic T cells.

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Cytotoxic T Cells (TC)

T cells that directly kill infected or cancerous cells.

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B Cells

White blood cells that produce antibodies, involved in humoral immunity.

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Antibodies

Proteins that bind to specific antigens, neutralizing them or marking them for destruction.

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Humoral Immunity

Immunity mediated by antibodies, primarily targeting extracellular pathogens.

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Cellular Immunity

Immunity mediated by T cells, primarily targeting intracellular pathogens.

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T-Dependent Humoral Response

A type of humoral response that requires the help of helper T cells to activate B cells.

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T-Independent Humoral Response

A type of humoral response that doesn't require T cell help, triggered by strong antigens directly.

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