Questions and Answers
Who first developed the process of colony purification on solid media?
What was the first successful solid medium reported for colony purification of bacteria?
What was the first virus shown to be the specific cause of a disease?
What is the primary function of ribosomes in bacterial cells?
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What is a plasmid?
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The 70S prokaryotic ribosome consists of what?
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One of the principal functions of bacterial pili is to:
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The term lysogeny refers to what?
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What is axenic culture used for?
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Which genera is known for producing bacterial endospores?
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What do cocci, rods, and spiral refer to?
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Psychrophiles are organisms that grow best at what temperatures?
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Which differential medium is specifically used for cultivating bacteria from the intestines?
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What is a phage?
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What is one way bacteria generate ATP?
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What characterizes phototrophs?
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What type of media allows for identification of haemolytic bacteria when blood is added?
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Which statement accurately describes Listeria monocytogenes?
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What type of media is characterized by allowing only salt-tolerant bacteria to grow?
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How is generation time best defined?
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What does the term 'facultative anaerobe' indicate about an organism?
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Which of the following antibiotics is considered bactericidal?
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Which media type uses specific nutrients to support the growth of fastidious organisms?
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What does it mean for a bacteria to be psychrotolerant?
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What is the main characteristic of a commensal bacterium?
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Which option describes a bacterial enterotoxin?
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Which organism is primarily responsible for transmitting malaria?
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What is the result of addition of eosin-methylene blue to a culture medium?
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Which process is studied during DNA hybridization between two bacterial strains?
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Which terminology describes an organism that requires oxygen for growth?
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Which type of bacteria is primarily involved in dental plaque formation and associated diseases?
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What is a characteristic of an onco-virus?
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Study Notes
Axenic Culture
- Defined as a culture free from any other living organisms, ensuring study of a single type of organism.
Mycelium
- A network of fungal filaments (hyphae), crucial for nutrient absorption and growth.
Bacterial Endospores
- Resistant structures formed by certain genera (e.g., Bacillus, Clostridium) for survival in harsh conditions.
Bacterial Shapes
- Bacteria can be classified based on shape: cocci (spherical), rods (bacilli), and spirals (spirilla).
Psychrophiles
- Organisms that thrive at low temperatures, generally below 15°C.
Bacterial Endospore Core
- Composed of dipicolinic acid and calcium, protecting genetic material during adverse conditions.
Differential Medium for Intestinal Bacteria
- McConkey agar specifically cultivates and differentiates bacteria from the intestines.
Phage Definition
- A virus that infects and replicates within bacteria, specifically a bacteriophage.
Denaturing Gradient Gel Electrophoresis (DGGE)
- A method used for microbial community analysis, allowing differentiation at sub-species levels.
Chemical Sterilization Technique
- Ethylene oxide is a recognized chemical method for sterilization.
ATP Generation in Bacteria
- ATP is generated by utilizing a proton gradient created by protons pumped out of the cell membrane.
Phototrophs
- Organisms that harvest energy from light, which may also utilize carbon dioxide or other fixed sources.
Nosocomial Infection
- An infection acquired in a healthcare setting, often resistant to treatment.
Nitrogen Fixation by Rhizobium
- The conversion of atmospheric nitrogen into ammonia, a form usable by plants.
Prophage
- A phage that has integrated its genome into the host bacterium's DNA.
Drinking Water Microorganisms Reduction
- Common methods include chlorination or filtration to reduce microbial populations.
Coliform Definition
- A group of bacteria commonly used as an indicator for fecal contamination in water.
Effluent Treatment Leading to Methane Release
- Anaerobic digestion processes typically produce methane from organic waste.
Macrophage Role
- A type of immune cell that engulfs and digests pathogens and cellular debris.
Commensal Bacterium
- A bacterium that lives in association with a host without causing harm.
Bacterial Enterotoxin
- A toxin produced by bacteria that acts on the intestines, leading to diarrhea or vomiting.
Oncovirus
- A virus capable of inducing cancer in host cells.
Scrapie
- A neurodegenerative disease affecting sheep and goats, caused by prion proteins.
Standard Plate Count Calculation
- If 38 colonies grew from a 0.1 ml sample diluted to 10^-4, the original sample had approximately 380,000 cells/ml.
Bacterial Growth Calculation
- Population density will increase from 400 CFU/ml to 12,800 CFU/ml after two hours if the bacterium divides every 40 minutes during log phase.
Plasmid Definition
- A self-replicating, extrachromosomal DNA molecule found in bacteria that can carry genes.
Micronutrient Example
- Essential nutrients needed in small quantities for microbial growth, such as zinc or copper.
Selective Media Example
- Eosin-methylene blue agar only allows the growth of coliform bacteria, exemplifying selective media.
Obligate Aerobe Definition
- An organism that requires oxygen for survival and growth.
Bactericidal Agents
- Substances that kill bacteria, as opposed to merely inhibiting their growth.
DNA Hybridization Studies
- A technique that compares nucleotide sequences between two bacterial species.
Heterotrophic Bacteria
- Bacteria that obtain carbon from organic sources, differentiating them from autotrophs.
Bacterial Plaque Contributors
- Species such as Streptococcus mutans are linked to dental problems like caries and gingivitis.
Gram Positive Cell Characteristics
- Typically thicker peptidoglycan layers in the cell wall, leading to a positive reaction in Gram staining.
Endospore Destruction
- Autoclaving effectively destroys bacterial endospores through high temperature and pressure.
Three Domains of Life
- Extensive nucleotide analysis has divided organisms into Archaea, Bacteria, and Eukarya.
Protists Classification
- Protists are classified under eukaryotes, distinct from prokaryotes like bacteria.
Malaria Carriers
- Mosquitos are the primary carriers, specifically Anopheles species which transmit the Plasmodium parasite.
Colony Purification Pioneer
- C. Robert Koch is credited with developing the process of colony purification on solid media.
First Successful Solid Medium
- Agar was the first solid medium successfully utilized for isolating bacterial colonies.
First Disease-Causing Virus
- Tobacco mosaic virus is known as the first virus identified to be the cause of a specific disease.
Ribosome Function in Bacteria
- Ribosomes are responsible for polypeptide synthesis, essential for protein production.
70S Prokaryotic Ribosome Structure
- Comprises a 50S subunit and a 30S subunit, facilitating protein synthesis in bacterial cells.
Bacterial Pili Functions
- Serve primarily to adhere bacteria to host cells and surfaces, enhancing pathogenicity.
Lysogeny Definition
- Describes the state in which a bacterium incorporates phage DNA into its genome without cell lysis.
Plasma Membrane Significance
- It selectively allows passage of molecules, maintaining the internal environment of the cell.
Blood Addition to Culture Media
- This method enables differentiation of haemolytic bacteria, exemplifying differential media usage.
Listeria monocytogenes Characteristics
- A Gram positive, psychrotolerant facultative anaerobe capable of growth at refrigeration temperatures.
Salt Tolerance in Bacteria
- Addition of salt to media is an example of selective media that allows only salt-tolerant organisms to grow.
Generation Time Definition
- Refers to the time required for a population of bacteria to double in number.
Facultative Anaerobe Behavior
- Organisms that can utilize oxygen for growth but can also survive in its absence.
Bactericidal vs. Bacteriostatic Agents
- Only specific antibiotics like chloramphenicol, oxytetracycline, ampicillin, and erythromycin are noted, with none classified purely as bactericidal.
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Description
Test your knowledge on fundamental microbiology concepts, including colony purification methods and the role of ribosomes in bacterial cells. This quiz explores significant developments in microbiology and key cellular components. Ideal for students looking to reinforce their understanding of microbiological principles.
