Who developed the Binomial Linnaean Scheme?
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Carl Linnaeus.
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Who developed the Binomial Linnaean Scheme?
Carl Linnaeus.
List some industrial applications of bacteria.
Wastewater treatment, cheese and yoghurt production, antibiotics, and other chemicals.
What does bactericidal mean?
Killing bacteria.
Who developed the Acid-fast Stain and in what year?
Paul Ehrlich in 1882.
What is the generation time of Bacillus cereus under optimal conditions at 37°C?
28 minutes
What is normal flora?
Harmless bacteria found on the body.
What is synthesized by bacteria during the oxidation of organic compounds?
ATP (adenosine triphosphate).
How long does it take for Escherichia coli to double under optimal conditions at 37°C?
12.5 minutes
How do bacteria contribute to the environment?
Through recycling and nitrogen fixation.
How does budding relate to mitotic cell division?
Budding is a form of mitotic cell division.
What is osmotic pressure?
Osmotic pressure is the pressure exerted on bacteria by their environment, such as water and salt.
What are the main types of cells compared in the text?
Bacterial and fungal cells.
Who was Robert Hermann Koch?
A German physician who developed Koch's postulates.
What significant microbiological invention did Charles Chamberland create in 1879?
The Autoclave
What is the purpose of differential or indicator media in microbiology?
To demonstrate biochemical or other features that help differentiate different types or species of microorganisms.
What are examples of ionizing radiation used for sterilization?
X-rays, gamma rays, and high-speed electrons.
What is bacterial growth?
An increase in bacterial number but not in size.
What is the binomial nomenclature for Helicobacter pylori?
Helicobacter pylori
In what year were Koch's postulates developed?
What does a phylogenetic tree represent?
It shows the forms of life.
What is chemically defined media?
Media with a known chemical composition, used for laboratory analysis of compounds produced by specified bacteria.
What type of organisms are bacteria in terms of metabolism?
Chemoheterotrophic organisms.
What is budding in the context of microbial division?
Budding is a form of asexual reproduction where new organisms form from outgrowths (buds) of mature organisms.
What are the important parts of a bacterial cell?
Important parts of a bacterial cell include the cell wall, plasma membrane, cytoplasm, ribosomes, nucleoid, and sometimes structures like flagella, pili, and capsules.
In what temperature range do mesophiles grow best?
25°C to 45°C
What is the K antigen?
Capsular polysaccharide.
How much energy is generated from fermentation compared to complete glucose oxidation?
Less energy is generated from fermentation, which is an incomplete form of glucose oxidation.
What are the two major components of the Gram-positive cell wall?
Peptidoglycan (murein) and teichoic acids.
What happens to molecules when chemical bonds are broken due to increased temperature?
Changes in the three-dimensional structure occur, inhibiting or destroying the molecules' ability to function properly.
What is the most commonly used tool for bacterial classification?
Gram staining results.
Which bacterium causes stomach and duodenal ulcers and grows at a low pH but is not classified as an acidophile?
Helicobacter pylori.
Why does the number of organisms present affect the sterilization process?
A higher number of organisms may require more time or higher temperatures to achieve complete sterilization.
How does temperature affect bacterial growth?
Temperature affects the rate of bacterial metabolism and enzyme activity, with different bacteria having optimal growth temperatures.
What is the crude death rate for infectious diseases in the United States between 1900 and 1996?
The crude death rate for infectious diseases in the United States between 1900 and 1996 is not specified in the provided text.
What significant medical development did Calmette and Guérin achieve in 1921?
They developed the BCG vaccine for tuberculosis.
What can filters with a pore size of 0.22 µm to 0.45 µm remove?
Most bacteria, but not mycoplasma or viruses.
What is disinfection in microbiology?
Disinfection is the process of killing most microbial forms except some resistant organisms or bacterial spores.
What is the O antigen?
Outer membrane lipopolysaccharide (LPS).
What is fermentation in the context of bacterial metabolism?
Fermentation is a type of metabolism where an organic compound, rather than oxygen, is the terminal electron (or hydrogen) acceptor.
What is the purpose of using radiation in sterilization?
To kill or inactivate microorganisms.
What are the two types of heat used in sterilization?
Dry heat and moist heat.
Why might some bacteria not be grown in a laboratory setting?
They may have specific nutritional requirements or conditions that are difficult to replicate in the lab.
What is selective media?
It contains ingredients that inhibit the growth of some organisms while enhancing the growth of others.
At what temperature is most bacterial growth incubated in laboratory settings?
37°C (98.6°F)
What is the minimum temperature for bacterial growth?
5°C
What is the pore size of filters that can retain all viruses and some large proteins?
0.01 µm.
What are examples of non-ionizing radiation used for sterilization?
Ultraviolet light and infrared light.
What is the optimum temperature for bacterial growth?
25°C
What types of instruments are cleaned with low-level disinfectants?
Noncritical instruments and devices that do not penetrate mucosa surfaces or sterile tissues.
Can you name an example of an item that requires high-level disinfection?
Endoscopes.
What are the criteria for selecting antiseptic agents?
Safety and efficacy.
What are the two main types of heat used in sterilization?
Dry heat and moist heat.
Why is it important to know the minimal concentration of antibiotics?
To determine the minimal concentration of antibiotics that can be used.
What are growth media?
Growth media are substances used to support the growth of microorganisms in a laboratory setting.
What are the two main types of cells based on modern classification?
Prokaryotic and Eukaryotic cells.
What is the temperature preference of Mycobacterium leprae, the causative agent of leprosy?
Mycobacterium leprae prefers low temperatures.
How is the species name written in binomial nomenclature?
The species name is Latinized, written in italics, and begins with a small letter.
What is metabolism in bacteria?
A biological process that converts food and other substances into energy and other metabolites that keep the cell viable.
What is an indirect method for determining bacterial numbers?
Turbidity test.
What are some examples of ingredients used in selective media?
Dyes and antimicrobics.
What ingredients are commonly found in differential media?
Carbohydrates and a pH indicator.
What is the purpose of growth media in microbiology?
To identify pathogens.
What are intermediate-level disinfectants used for?
For cleaning surfaces or instruments without bacterial spores and highly resilient organisms, such as laryngoscopes and anesthesia breathing circuits.
What type of bacteria optimally grow in alkaline pH values greater than 8?
Alkalophiles.
What is a disinfectant?
A disinfectant is a substance or method used to kill microbes on surfaces.
What does PSI stand for in the context of autoclave sterilization?
PSI stands for pounds per square inch.
What is the H antigen?
Flagellar protein.
Why is ionizing radiation referred to as cold sterilization?
Because it has high penetration power and does not increase temperature.
Who developed Koch's postulates?
Robert Koch and Friedrich Loeffler.
What is growth media?
A solid, liquid, or semi-solid designed to support the growth of microorganisms.
What is a direct method for determining bacterial numbers?
Counting colony forming units (CFU).
When are selective media used?
When specific pathogenic organisms are sought in sites with an extensive normal flora.
Who is credited with creating the first microscope and observing 'little animals'?
Anton van Leeuwenhoek in 1677.
What is MacConkey agar?
A selective and differential medium that inhibits certain Gram-positive bacteria and allows Gram-negative bacteria to grow.
Name some diseases caused by bacteria.
Cholera, Syphilis, Anthrax, Leprosy, Bubonic plague, and Tuberculosis.
What are the three types of hemolysis that can be identified using RBCs in differential media?
Alpha, beta, and gamma hemolysis.
What is the result of bacterial growth?
A colony, which is an aggregation of cells arising from a single parent cell.
What are high-level disinfectants used for?
For items involved in invasive procedures that cannot withstand sterilization.
Why is it important to know the bacterial number or bacterial growth?
It is important in identifying and diagnosing bacterial diseases.
What type of bacteria optimally grow in acidic pH values less than 6?
Acidophiles.
What occurs during the lag phase of the bacterial growth curve?
Bacteria adapt to their new environment and prepare for cell division, but there is little to no increase in cell number.
What is the temperature preference of Treponema pallidum, the causative agent of syphilis?
Treponema pallidum prefers low temperatures.
What characterizes the log (exponential) phase in the bacterial growth curve?
Rapid cell division and exponential increase in the number of bacteria.
What are the two main types of chemical methods of sterilization?
Liquid and gas.
Which bacteria are known for producing antibiotics?
Streptomyces species.
In what forms can growth media be found?
Broth or agar.
Which color represents eukaryotes in the phylogenetic tree?
Red.
What are antigenic determinants?
Antigenic characters that define serotypes within species, especially in Enterobacteriaceae.
Why is steam an effective means of sterilization in an autoclave?
Because of its high penetrating capacity and ability to give off large amounts of heat to surfaces without direct contact.
What can affect the diagnosis and treatment of bacterial infections?
Different factors, including bacterial growth requirements and specimen collection methods.
What is another name for complex media?
Nutrient media.
How can growth media be classified based on its ability to identify different types of bacteria?
Selective and Indicator (differential).
How can you see bacteria under a microscope?
Bacteria can be seen under a microscope by using staining techniques such as Gram staining, which helps to differentiate bacterial species and enhances visibility.
In what temperature range do thermophiles grow best?
45°C to 70°C
What is selective growth media?
A type of growth media that allows the growth of certain bacteria while inhibiting others.
What is the use of cell parts for bacteria and for microbiology labs?
Cell parts like the cell wall provide structural support and protection, the plasma membrane controls the movement of substances in and out of the cell, ribosomes are involved in protein synthesis, and the nucleoid contains genetic material. In microbiology labs, understanding these structures helps in identifying bacteria, studying their functions, and developing antibiotics.
What are the three temperature ranges in which bacteria can be classified based on their growth preferences?
Cold (psychrophiles), moderate (mesophiles), and high (thermophiles) temperatures.
What systems are essential for generating steam in an autoclave?
Water heating system or steam generating system.
What are the three major categories of bacteria based on oxygen use?
Obligate aerobes, obligate anaerobes, and facultative anaerobes.
What is bacteriology?
The study of bacteria, a branch of microbiology.
What is a species in biological classification?
A species is a group of organisms capable of interbreeding and producing fertile offspring.
Why is the type of material from which an organism is to be eradicated important in sterilization by heat?
Different materials can withstand different levels of heat and may affect the efficiency of the sterilization process.
What leads to the death (decline) phase in the bacterial growth curve?
Nutrient depletion and accumulation of toxic waste products cause the death rate to exceed the growth rate.
Who proposed the modern classification of bacteria based on rRNA?
Carl Woese in 1987.
Who identified Neisseria gonorrhoeae in 1879?
Albert Neisser
Into how many major domains did Carl Woese divide living things?
Three major domains.
What is the pore size range for filters used to sterilize solutions sensitive to heat?
0.22 µm to 0.45 µm.
What are the two types of radiation used for sterilization?
Ionizing radiation and non-ionizing radiation.
What are the basic requirements for bacterial growth?
Nutrients, temperature, pH, oxygen levels, and moisture.
Which color represents archaea in the phylogenetic tree?
Green.
In what temperature range do psychrophiles grow best?
0°C to 18°C
What significant contribution did Joseph Lister make to surgery in 1867?
He introduced the use of phenols as an antiseptic.
What pH range do most bacteria prefer for optimal growth?
Most bacteria prefer a neutral pH of 7.0.
Which color represents bacteria in the phylogenetic tree?
Blue.
What are the three categories of disinfection?
What are the components of sunlight that contribute to its bactericidal effect?
Heat and UV light.
Which organisms commonly undergo budding?
Certain bacteria, yeasts, and protozoans.
What are the characteristics of bacterial growth?
Bacterial growth is characterized by phases: lag phase, log phase, stationary phase, and death phase.
Who developed the Gram Stain and in what year?
Christian Gram in 1884.
What is the purpose of using chemical agents in antisepsis?
To inhibit or eliminate microbes on skin or living tissues.
Why is drying considered a method of sterilization?
Because 4/5 of bacterial cell weight is water, and drying removes this water.
What is nomenclature in microbiology?
The procedure of assigning names to organisms using the Binomial Linnaean Scheme by Carl Linnaeus.
What are the chemical requirements for bacteria?
Many of the chemical requirements for bacteria are the same as for human cells.
When was Robert Hermann Koch born and when did he die?
He was born on 11 December 1843 and died on 27 May 1910.
How can bacterial metabolic activity be used to determine bacterial numbers?
By measuring their metabolic activity and cell products.
What is the purpose of measuring bacterial growth?
To determine the number of bacteria present.
At what temperature does maximum bacterial growth occur?
35°C
What are the conditions required to achieve sterility in an autoclave?
A holding time of at least 15 minutes at 121°C (250°F) at 15 psi (100 kPa) above atmospheric pressure.
How does increased temperature affect bacterial growth?
Increased temperature breaks chemical bonds, causing changes in the three-dimensional structure of molecules, which can inhibit or destroy their ability to function properly.
What types of radiation are used in cold sterilization?
X-rays, gamma rays, and cosmic rays.
What are the basic requirements needed for bacterial growth in the lab?
Nutrients, temperature, pH, oxygen levels, and moisture.
What is the degree of disinfection for intermediate-level disinfectants?
They are used for cleaning surfaces or instruments without bacterial spores and highly resilient organisms.
Are disinfectants effective against all bacteria or spores?
No, disinfectants are not effective against all bacteria or spores.
Why are nutrients important for bacterial growth?
Nutrients provide the essential elements and energy sources needed for bacterial metabolism and reproduction.
What is the degree of disinfection for low-level disinfectants?
They are used to treat noncritical instruments and devices that do not penetrate mucosa surfaces or sterile tissues.
What is mean generation time in bacterial growth?
The mean generation time is the average time it takes for a bacterial population to double in number.
How long does Mycobacterium tuberculosis take to double under optimal conditions at 37°C?
18-24 hours
What forms the mesh-like layer outside the plasma membrane in most bacteria?
Peptidoglycan (murein).
What factors can influence the mean generation time of bacteria?
Factors such as temperature, nutrient availability, pH, and oxygen levels can influence the mean generation time of bacteria.
What type of cells are classified as Eucaryota?
Eucaryotic cells.
What is the generation time of Treponema pallidum under optimal conditions at 37°C?
30 hours
Is sterilization effective against bacterium spores?
Yes, sterilization is effective to kill bacterium spores.
What does the nomenclature in microbiology refer to?
The system of naming microorganisms.
Why is formaldehyde gas considered hazardous?
It is carcinogenic.
What does moist heat cause in microorganisms?
Denaturation and coagulation of proteins.
Do bacteria have a nuclear membrane?
No, they are prokaryotes.
What are the two types of growth media?
Chemically defined media and complex media.
Who discovered penicillin and in what year?
Alexander Fleming discovered penicillin in 1928.
What is complex media?
Media with an unknown exact chemical composition, containing numerous ingredients and extracts derived from plants or meats.
What is growth media in the context of bacterial growth?
Substances that provide the necessary nutrients for bacteria to grow in a laboratory setting.
How do bacteria obtain energy?
From the oxidation of organic compounds (carbohydrates, lipids, and protein).
What is the smallest taxonomic group that contains organisms of different species?
Genus.
What does it mean when bacteria are described as fastidious in a laboratory setting?
They have specific and complex nutritional requirements for growth.
What are the four phases of the standard bacterial growth curve?
Lag phase, log (exponential) phase, stationary phase, and death (decline) phase.
What are the seven levels of Linnaeus' hierarchical system of classification from largest to smallest?
Kingdom, Phylum, Class, Order, Family, Genus, Species.
What are the typical capacities of an autoclave chamber?
400 to 800 liters.
What type of growth does fermentation support?
Fermentation supports anaerobic growth.
What is another example of an item that requires high-level disinfection?
Surgical instruments.
What is the purpose of blood agar in microbiology?
Blood agar is used to identify and differentiate bacterial pathogens based on their hemolytic properties.
How is the genus name written in binomial nomenclature?
The genus name is Latinized, written in italics, and begins with a CAPITAL letter.
What degree of disinfection do high-level disinfectants provide?
High-level disinfection.
What types of microbes are targeted by sterilization?
Bacteria, mycobacteria, viruses, and fungi.
What are halophilic organisms?
Halophilic organisms are those that can live in the presence of high levels of salt.
What is the singular form of 'bacteria'?
Bacterium.
What is the mechanism of killing organisms using dry heat?
Dehydration and oxidation of organisms, and protein denaturation.
Why do certain diseases have variable temperature requirements?
Different bacteria have specific temperature preferences that affect their growth and ability to cause disease.
Psychrophile bacteria optimally grow at which temperature?
Around 15°C.
How do oxygen levels influence bacterial growth?
Oxygen levels determine whether bacteria can grow aerobically or anaerobically, with some bacteria requiring oxygen and others being inhibited or killed by it.
What instrument is used to measure temperature in an autoclave?
Thermometer or temperature meter.
How is the growth rate of bacteria typically expressed?
The growth rate of bacteria is typically expressed as the number of generations per unit time, often per hour.
How are microorganisms named and classified?
Through a systematic process of nomenclature and classification.
Why is moisture important for bacterial growth?
Moisture is necessary for bacterial metabolic processes and nutrient transport.
What are the two methods of pasteurization and their respective temperatures and durations?
Holder method: 63°C for 30 minutes; Flash method: 72°C for 15-20 seconds followed by quick cooling to 13°C.
What is the term for the time required for a cell to divide and double its number?
Generation time.
At what wavelength does UV destroy microorganismal DNA?
2537 Angstroms.
What is the clinical implication of bacterial growth?
Understanding bacterial growth helps in diagnosing infections, determining antibiotic treatment, and controlling the spread of bacteria.
What is bacterial growth?
Bacterial growth refers to the increase in the number of bacterial cells in a population.
What is the generation time range for Staphylococcus aureus under optimal conditions at 37°C?
27-30 minutes
What is indicator (differential) growth media?
A type of growth media that distinguishes between different types of bacteria based on their biological characteristics.
What is gamma radiation used for in sterilization?
Sterilizing plastics, syringes, swabs, catheters, etc.
What types of items can be sterilized using a hot air oven?
Laboratory glass, flasks, instruments with sharp cutting edges, and powders.
Why are growth media important for bacterial growth?
Growth media provide the necessary nutrients and environmental conditions for bacteria to grow and reproduce.
What is a disadvantage of using heat for sterilization?
It is not suitable for heat-sensitive materials and toxic chemicals.
What is incineration used for in sterilization?
Incineration is used for sterilizing needles, inoculating wires, glassware, and other objects that are not destroyed in the incineration process.
What happens during the Lag Phase of bacterial growth?
Bacteria adapt to their environment and prepare for future growth, but do not yet multiply significantly.
What is the genus name in Helicobacter pylori?
Helicobacter
What was Louis Pasteur's contribution to the understanding of disease?
He demonstrated that microorganisms do not arise by spontaneous generation.
What is the selective property of MacConkey agar?
MacConkey agar contains bile salts and crystal violet, which inhibit the growth of Gram-positive bacteria, making it selective for Gram-negative bacteria.
What changes occur in bacteria during the stationary phase?
Increased expression of genes related to repair, antioxidant metabolism, and nutrient transport.
How are bacteria classified based on their carbon acquisition?
Bacteria are classified as chemoheterotrophs or chemoautotrophs based on how they acquire carbon.
What is considered 'germicidal UV'?
Short range UV (UVC).
Which bacteria lack a cell wall?
Mollicutes (Mycoplasma) and Chlamydia.
What happens during the death phase of bacterial growth?
There is a decrease in the number of bacteria, indicating it is not a growth phase.
How do bacteria reproduce?
By binary fission.
What was the impact of Semmelweis and Lister's work on public health?
It led to great advances in public health that initiated the decline in disease and death.
What is a microaerophile?
A bacterium that requires only low levels of oxygen for growth.
What is the typical size range for most bacteria?
1–10 micrometers (um).
What occurs during the lag phase of bacterial growth?
Bacteria adapt to their environment and prepare for cell division, but there is no increase in cell number.
What is the role of nitrogen in biological systems?
Nitrogen is involved in protein synthesis and is part of the structure of nucleic acids.
What does it mean for something to be sterile?
It is free of life of every kind.
What are the general categories of growth requirements for bacteria?
Physical and chemical requirements.
How does the amount of organic material present influence disinfection?
Organic material can protect microorganisms from disinfectants, reducing their effectiveness.
What is a limitation of infrared radiation in sterilization?
It has no penetrating ability.
How do temperature and time influence sterilization by heat?
Higher temperatures and longer exposure times generally increase the effectiveness of sterilization.
What is sterilization in microbiology?
Complete removal of all kinds of microbes (bacteria, mycobacteria, viruses, and fungi) by physical or chemical methods.
What is the F antigen?
Pilus or fimbriae protein.
Name three types of anaerobic bacteria.
Lactobacillus, Clostridium, and Bacteroides.
Who divided the Eubacteria into 11 divisions based on 16S ribosomal RNA sequences in 1987?
Carl Woese.
How does an excess of hydrogen ions affect protein structure?
It causes bonds to break, changing the three-dimensional structure and destroying protein function.
How does the sporing capacity of an organism influence sterilization by heat?
Organisms with sporing capacity are more resistant to heat and require more stringent conditions for sterilization.
According to energy and carbon source, what is the nutritional type of pathogenic bacteria?
Chemoheterotrophs.
What role does pH play in bacterial growth?
pH affects enzyme activity and membrane transport; different bacteria have specific pH ranges for optimal growth.
What are the two main types of growth media?
The two main types of growth media are liquid (broth) media and solid (agar) media.
What element do all biological molecules contain?
Carbon.
What is red heat used for in sterilization?
To sterilize metallic objects by holding them in flame until they are red hot.
Can there be degrees of sterility?
No, an item is either sterile or not sterile.
Anaerobic bacteria follow which type of Chemoheterotroph metabolism?
Fermentation or anaerobic respiration.
Name two examples of gas chemical sterilants.
Ethylene oxide and ozone.
How are mean generation time and growth rate related?
Mean generation time and growth rate are inversely related; a shorter mean generation time corresponds to a higher growth rate.
What type of organisms are bacteria?
Unicellular.
What is a key feature of eukaryotic cells?
They have a true nucleus and membrane-bound organelles.
How did Pasteur's Swan-Necked Flask experiment work?
Pasteur's Swan-Necked Flask experiment involved boiling broth in a flask with a long, curved neck. The design allowed air to enter but trapped airborne microorganisms in the neck, preventing them from reaching the broth.
What are the main uses of UV radiation in sterilization?
Air purification and water purification in hospitals.
What is Tyndallisation and who is it named after?
Tyndallisation is a sterilization method involving exposure to 100°C for 20 minutes for 3 consecutive days, named after John Tyndall.
How do bacteria reproduce?
By binary fission.
What is metabolism in bacteria?
Various biological processes that convert food and other substances into energy and other metabolic by-products.
What are some trade names for iodine compounds?
Betadyne, Providone.
What are the physical methods of sterilization mentioned?
Moist heat, pasteurization, and Tyndallisation.
What is the optimal temperature range for thermophiles?
Thermophiles thrive at temperatures between 45°C and 80°C.
What is the required time for sterilization at 140°C?
180 minutes.
When does the bud separate from the parent cell in budding?
The bud separates when it reaches the size of the parent cell.
What can improper specimen collection and culturing lead to?
Missed identification of the pathogen and wrong diagnosis.
Which methods are most commonly used for sterilizing most materials?
Steam (moist heat) and dry heat.
What components control the flow of steam in an autoclave?
Steam outlet and inlet valves.
What are the disadvantages of using ionizing radiation for sterilization?
It can penetrate human tissue and may cause genetic mutations.
What is the Germ Theory of Disease?
The Germ Theory of Disease states that microorganisms are the cause of many diseases.
What is the main focus of modern classification of bacteria?
The distinctive features of Prokaryotic and Eukaryotic cells.
Name two examples of liquid chemical sterilants.
Formaldehyde and glutaraldehyde.
What causes the stationary phase in bacterial growth?
Depletion of nutrients, leading to decreased metabolic activity and consumption of non-essential cellular proteins.
Who is associated with the development of the Germ Theory of Disease?
Louis Pasteur is one of the key figures associated with the development of the Germ Theory of Disease.
How many moles of ATP are derived from the oxidation of 1 mole of glucose in bacterial respiration?
38 moles of ATP.
What happens during binary fission?
The parent cell splits into two daughter cells.
What is the typical shape of bacteria?
Bacteria can be spherical (cocci), rod-shaped (bacilli), spiral (spirilla), or comma-shaped (vibrios).
In what year was Helicobacter pylori identified?
1984
Are humans more closely related to bacteria or fungi?
Humans are more closely related to fungi than to bacteria.
What factors influence the effectiveness of disinfectants?
Nature of the item to be disinfected, number of contaminants, amount of organic material present, type and concentration of disinfectant, and duration and temperature of exposure.
What are some common methods of sterilization?
Common methods of sterilization include autoclaving, dry heat, filtration, radiation, and chemical sterilants.
Give examples of objects that can be sterilized using flaming.
Glass plates, cotton wool, and glass slides.
What is the optimal temperature range for psychrophiles?
Psychrophiles thrive at temperatures below 15°C.
What is the chromosome topology in Procaryotic cells?
Circular.
What did Pasteur and Koch achieve in their studies?
They isolated specific agents and proved that they could cause disease.
What are some common methods of disinfection?
Common methods of disinfection include the use of chemical disinfectants such as alcohol, chlorine compounds, and hydrogen peroxide.
What is the required time for sterilization at 150°C?
150 minutes.
What is peptidoglycan (murein) composed of?
Sugars (N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)) and amino acids.
What is a hot air oven used for in sterilization?
It is used to sterilize items that do not get damaged by high temperatures, such as laboratory glass, flasks, instruments with sharp cutting edges, and powders.
How does osmotic pressure affect bacterial growth?
Osmotic pressure can inhibit bacterial growth.
What are the years of Carl Linnaeus's life?
1707-1778.
What type of bacteria can be identified using MacConkey agar?
MacConkey agar is used to identify and differentiate Gram-negative bacteria, particularly enteric pathogens.
What characterizes the log phase in the bacterial growth curve?
Rapid exponential growth and maximum nutrient metabolism.
What did the ancients believe about the origin of disease?
They believed disease was spontaneously generated.
What is the effect of ionizing radiation on DNA and other vital contents?
It is highly lethal to DNA and other vital contents.
What is an obligate anaerobe?
A bacterium that cannot survive in the presence of oxygen.
What type of cells are bacteria?
Single-celled.
Which sterilization method involves dry heat?
Incineration involves dry heat.
What is the first of Koch's postulates?
The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
What are Koch's postulates?
A set of criteria used to establish a causative relationship between a microbe and a disease.
What is the differential property of MacConkey agar?
MacConkey agar differentiates bacteria based on their ability to ferment lactose, with lactose fermenters producing pink colonies and non-fermenters producing colorless colonies.
What occurs during the Death Phase of bacterial growth?
The number of dying bacteria exceeds the number of new bacteria being produced, leading to a decline in the overall population.
How do chemoheterotrophs obtain carbon?
Chemoheterotrophs obtain carbon by breaking down other carbon molecules.
What is the most common gas vapor sterilant?
Ethylene oxide.
What does the Log Phase refer to in bacterial growth?
It is another term for the Exponential Growth Phase, where bacteria multiply at a constant and rapid rate.
What is the difference between a bacterial spore and a normal vegetative cell?
Bacterial spores are dormant, resistant to harsh conditions, and can survive without nutrients, while vegetative cells are active and metabolically functional.
What is a sterilant?
An agent or method used to remove or kill all microbes.
Why do bacteria experience rapid growth during the Exponential Growth Phase?
Because they have maximum nutrient availability and optimal metabolic conditions.
What are the physical methods of sterilization mentioned?
Red heat and flaming.
What is the optimal temperature range for mesophiles?
Mesophiles thrive at temperatures between 20°C and 45°C.
Are meiosis and mitosis present in Eucaryotic cells?
Yes, both are present.
What are chemoheterotrophs?
They include all pathogens and obtain energy (synthesis of ATP) from oxidation of organic compounds (carbohydrates, lipids, and protein).
What is a key characteristic of bacterial growth?
The ability to divide and double their number through binary fission.
What is the approximate concentration of bacteria in water?
Approximately a million bacteria per millimeter of water.
What are the main components of the cell envelope in Gram-positive bacteria?
The cell envelope in Gram-positive bacteria primarily consists of a thick peptidoglycan layer and teichoic acids.
What does septic mean?
The presence of pathogenic microbes in living tissue.
What are the three main mechanisms by which chemical disinfectants affect microorganisms?
What happens during the lag phase of bacterial growth?
Bacteria adapt to a new environment and exhibit high biosynthesis.
What are the two metabolic pathways that bacteria can follow?
Respiration and fermentation.
What happens during the stationary phase of the bacterial growth curve?
The rate of bacterial cell growth equals the rate of cell death, leading to a stable population size.
How does blood agar differentiate bacterial species?
Blood agar differentiates bacterial species based on their ability to hemolyze red blood cells, showing clear, greenish, or no zones around colonies.
Why is the human body an excellent incubator for pathogens?
The human body provides bacteria with optimal osmotic pressure, optimal temperature range, and optimal pH range.
Is binary fission a sexual or asexual method of reproduction?
Asexual reproduction.
In what year was Helicobacter pylori named?
What are the two main types of cells?
Prokaryotic and Eukaryotic cells.
What is a facultative anaerobe?
A bacterium that can grow with or without oxygen.
How many chromosomes do Eucaryotic cells typically have?
More than one.
What types of items can be sterilized using incineration?
Needles, inoculating wires, glassware, and other objects that are not destroyed in the incineration process.
What is sterilization?
Sterilization is the process of eliminating all forms of microbial life, including bacteria, viruses, spores, and fungi.
Who discovered bacteria and how?
Antonie van Leeuwenhoek discovered bacteria using a microscope he designed.
What are the four phases of bacterial growth in a closed system?
Lag phase, log (exponential) phase, stationary phase, and death (decline) phase.
What factors can affect the generation time of bacteria?
Environmental conditions such as temperature and pH level.
What is a physical indicator in sterilization?
A mixture designed to melt only after being subjected to relevant holding time.
What is an example of a microaerophile?
Campylobacter.
Are bacteria useful or harmful?
Bacteria can be both; they play essential roles in processes like digestion and nitrogen fixation but can also cause diseases.
Which type of cell is generally larger and more complex?
Eukaryotic cells.
How long can the generation time be for some bacterial species?
24 hours per generation.
What is disinfection?
The killing of most microbial forms.
What is antisepsis?
Antisepsis is the process of applying antiseptic agents to living tissue to reduce the possibility of infection, sepsis, or putrefaction.
What is a disinfectant?
A chemical substance used to kill microbes on surfaces but too toxic to be applied directly to tissue.
What domain do Mycobacterium tuberculosis and Escherichia coli belong to?
Bacteria
What are the conditions for sterilization using a hot air oven?
160°C for 2 hours.
Where on the human body can bacteria be found?
On body surfaces and membranes.
How does oxygen affect bacterial growth?
Oxygen is a specific growth requirement for some bacteria.
What is a key structural difference between Gram-positive and Gram-negative bacteria?
Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin peptidoglycan layer and an additional outer membrane.
What role do teichoic acids play in Gram-positive bacteria?
Teichoic acids provide structural support and help maintain cell shape in Gram-positive bacteria.
Give an example of an organism that undergoes budding.
Yeast is an example of an organism that undergoes budding.
What is the Exponential Growth Phase in bacterial growth?
It is the phase where the number of bacteria increases rapidly due to optimal conditions for growth.
What is an example of a bacterium named using the Binomial Linnaean Scheme?
Helicobacter pylori.
What is respiration in bacterial metabolism?
It is a type of metabolism that uses oxygen as a terminal hydrogen acceptor and derives 38 moles of ATP from the oxidation of 1 mole of glucose.
What happens during the Lag Phase of bacterial growth?
Bacteria adapt to their environment and prepare for future growth, but do not yet multiply.
What is a sterilant?
A material or method used to remove or kill all microbes.
What is an aerotolerant bacterium?
A bacterium that grows in oxygen but does not use it in metabolism.
Who was a key figure in disproving spontaneous generation and supporting the germ theory of disease?
Louis Pasteur (1822 - 1895).
What occurs during the Death Phase of bacterial growth?
The number of dying cells exceeds the number of new cells being produced, leading to a decline in the overall population.
How big are bacteria?
Bacteria typically range from 0.2 to 2.0 micrometers in diameter.
How does the nature of the item to be disinfected affect disinfection effectiveness?
Different materials may interact with disinfectants in various ways, affecting the overall effectiveness.
What is the typical generation time for most bacteria?
1-3 hours.
How do hypochlorites act as disinfectants?
Hypochlorites denature proteins.
What leads to the decrease in bacterial growth during the Stationary Phase?
Decreased metabolism and nutrient availability, along with increased toxic product accumulation.
What organism's spores are used as a biological indicator in autoclave sterilization?
Spores of Geobacillus stearothermophilus.
What happens during the stationary phase of bacterial growth?
The growth rate slows and stabilizes as the rate of cell division equals the rate of cell death.
Why are Geobacillus stearothermophilus spores used as a test organism in autoclave sterilization?
Because it is the toughest organism for an autoclave to destroy.
What type of organisms are made up of eukaryotic cells?
Plants, animals, fungi, and protists.
What are some trade names for phenols?
Cresol, Lysol, Tek-Trol.
What is the optimal temperature range for hyperthermophiles?
Hyperthermophiles thrive at temperatures above 80°C.
What chemical is commonly used for gas sterilization?
Ethylene Oxide.
What does aseptic mean?
The absence of pathogenic microbes.
What occurs during the lag phase of bacterial growth?
Bacteria adapt to their environment and prepare for cell division, but there is no increase in cell number.
Which sterilization method is suitable for glassware like Petri dishes, pipettes, beakers, and flasks?
Autoclave or Hot air oven.
What is an obligate aerobe?
A bacterium that requires oxygen for growth.
What is the most common method of bacterial reproduction?
Binary fission.
What time period is referred to as the first golden age of microbiology?
1875–1910.
What additional components can be found in the Gram-positive cell wall depending on the species?
Additional carbohydrates and proteins.
What type of cells are classified as Bacteria?
Procaryotic cells.
What are the two types of non-ionizing radiations used for sterilization?
Ultraviolet (UV) and Infrared (IR).
Where is murein (peptidoglycan) found?
Only in prokaryotes.
What is the species name in Helicobacter pylori?
pylori
What is the germ theory of disease?
The theory that microorganisms are the cause of many diseases.
Who showed how diseases spread before the first golden age of microbiology?
Semmelweis and Lister
What are the key chemical requirements for bacterial growth?
Phosphorous, Nitrogen, Carbon, and Oxygen.
What was the purpose of Pasteur's Swan-Necked Flask experiment?
The purpose of Pasteur's Swan-Necked Flask experiment was to demonstrate that microorganisms in the air were responsible for contaminating sterile solutions.
What is flaming in the context of sterilization?
Passing the object over a flame without allowing it to become red hot.
How do chemoautotrophs obtain carbon?
Chemoautotrophs obtain carbon from CO2.
What are the disadvantages of using ethylene oxide as a sterilant?
It is flammable, explosive, and potentially carcinogenic.
What is the fourth of Koch's postulates?
The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.
What did Sir William Osler describe as humanity's greatest enemy in 1896?
Fever.
What characterizes the log (exponential) phase of bacterial growth?
Rapid cell division and exponential increase in the number of bacteria.
Why is phosphorus essential for bacteria?
Phosphorus is essential for the synthesis of nucleic acids and ATP.
Where is infrared radiation most commonly used for purification?
In the operating room to purify air.
Why is it important for infectious organisms to meet specific growth requirements?
Increased numbers of pathogens help to defeat the host defense.
What is bacterial metabolism?
Bacterial metabolism refers to the chemical processes that occur within a bacterium to maintain life, including catabolism (breaking down molecules for energy) and anabolism (building up molecules for cellular functions).
Name a physical requirement for bacterial growth.
Temperature.
What is fermentation in bacteria?
A process that uses organic compounds as the terminal electron acceptor.
What is the ribosome size in Procaryotic cells?
70 S in the cytoplasm.
To which phylum does Escherichia coli belong?
Proteobacteria (G-ve)
Which disinfectants have limited effectiveness against mycobacteria?
Iodine
Which disinfectants have variable effectiveness against mycobacteria?
Phenols
What type of doors do autoclaves typically have?
Single or double doors with a locking mechanism.
What is the Exponential Growth Phase in bacterial growth?
It is the phase where bacteria undergo rapid exponential growth.
What is the growth rate in the context of bacterial growth?
The growth rate is the rate at which a bacterial population increases in number over a specific period of time.
What period is known as the first golden age of microbiology?
1875–1910
What is the purpose of using agar in solid growth media?
Agar is used to solidify the growth media, allowing for the isolation and observation of individual bacterial colonies.
Give examples of objects that can be sterilized using red heat.
Inoculating wires, needles, forceps.
What instrument is used to measure pressure in an autoclave?
Pressure meters.
What type of growth does respiration support in bacteria?
Aerobic growth.
How many chromosomes do Procaryotic cells typically have?
One.
For what types of products is pasteurization used?
Heat-sensitive liquid and pharmaceutical products.
Which two scientists are known for pioneering studies in medical microbiology?
Pasteur and Koch
What is a chemical indicator in sterilization?
Strips or tapes that change color once the correct conditions have been met.
What is the principle behind Tyndallisation?
The first exposure kills all bacteria and spores, which will germinate in a favorable medium and be killed on subsequent occasions.
What is the generation time of bacteria?
The time it takes for a bacterial population to double.
What are the methods of sterilization?
Autoclave, Hot air oven, Chemical and gas (Ethylene Oxide), Filtration, Radiation (Gamma, UV).
What is meant by 'The first golden age of microbiology'?
The first golden age of microbiology refers to the period in the late 19th century when many foundational discoveries were made, including the identification of many pathogens and the development of techniques for studying microorganisms.
How do bacteria obtain energy through respiration?
By using oxygen as the electron acceptor, deriving 38 moles of ATP from the oxidation of 1 mole of glucose, yielding 380,000 calories.
Mention some historic landmarks in microbiology.
Some historic landmarks in microbiology include the discovery of the microscope, the development of germ theory, and the identification of specific bacteria causing diseases.
What is the importance of understanding bacterial growth phases?
It helps in controlling bacterial infections and optimizing bacterial cultures in industrial and laboratory settings.
What is bacterial growth?
Bacterial growth refers to the increase in the number of bacterial cells through cell division.
What is an example of a biofilm formed by bacteria?
Dental plaque on teeth.
List 3 advantages of bacteria.
Three advantages of bacteria are: 1) They play a crucial role in nutrient cycling, such as nitrogen fixation. 2) They are used in the production of antibiotics and other pharmaceuticals. 3) They are essential in food production processes like fermentation.
What is the Germ Theory of Disease?
The theory that microorganisms are the cause of many diseases.
What characterizes the Stationary Phase in bacterial growth?
The growth rate slows and stabilizes as the number of new bacteria equals the number of dying bacteria.
What experiment did Louis Pasteur use to support the Germ Theory of Disease?
Louis Pasteur used the Swan-Necked Flask experiment to support the Germ Theory of Disease.
What characterizes the Stationary Phase in bacterial growth?
The growth rate slows down and stabilizes as nutrient levels decrease and waste products accumulate.
Bacterial growth follows three phases, describe each:
Lag phase: Bacteria adapt to new environment; Log phase: Rapid cell division and growth; Stationary phase: Nutrient depletion slows growth and death rate equals birth rate.
What is sterilization?
The removal of all forms of life of every kind by physical or chemical methods.
What is an example of a facultative anaerobe?
Staphylococcus.
What is a key difference between human cells and bacterial cells?
Human cells are eukaryotic, while bacterial cells are prokaryotic.
Which type of cell is generally smaller and simpler in structure?
Prokaryotic cells.
What was the outcome of Pasteur's Swan-Necked Flask experiment?
The outcome of Pasteur's Swan-Necked Flask experiment was that the broth remained sterile, proving that microorganisms from the air were necessary for contamination.
Can any chemical solution safely sterilize instruments immersed in it?
No, there is no safe chemical solution that will sterilize instruments immersed in it.
What additional observation was later added to Koch's postulates?
Antibodies usually develop during the course of the disease.
Where can bacteria be found?
Bacteria are ubiquitous, meaning they can be found everywhere.
What is the approximate concentration of bacteria in soil?
Approximately 40 million bacteria per gram of soil.
What are the conditions for sterilization using an autoclave?
121°C, 15 Ib pressure, 15 minutes.
What exposure is required to destroy Geobacillus stearothermophilus spores in an autoclave?
15 minutes at 121°C.
How do duration and temperature of exposure affect disinfection?
Longer exposure times and appropriate temperatures can enhance the effectiveness of disinfectants.
Name some anaerobic bacteria.
Lactobacillus, Clostridium, Bacteroides.
What are the phases of bacterial growth in a culture?
Lag phase, log (exponential) phase, stationary phase, and death (decline) phase.
What does bacteriostatic mean?
Inhibiting bacterial multiplication. Bacteriostatic action is reversible by removal or inactivation of the agent.
What happens during the log (exponential) phase of bacterial growth?
Bacteria rapidly divide and the population increases exponentially.
How does the peptidoglycan layer differ between Gram-positive and Gram-negative bacteria?
The peptidoglycan layer is much thicker in Gram-positive bacteria compared to the thin layer found in Gram-negative bacteria.
What is the required time for sterilization at 180°C?
18 minutes.
What is the composition and function of the bacterial cell membrane?
The bacterial cell membrane is composed of a phospholipid bilayer with embedded proteins. Its function is to regulate the movement of substances in and out of the cell and to facilitate communication and metabolic processes.
What is a key feature of prokaryotic cells?
They lack a true nucleus and membrane-bound organelles.
What is the second of Koch's postulates?
The microorganism must be isolated from a diseased organism and grown in pure culture.
What is the mechanism of action of alcohols as chemical disinfectants?
Alcohols precipitate proteins and denature lipids.
What is the third of Koch's postulates?
The cultured microorganism should cause disease when introduced into a healthy organism.
Are bacteria metabolically active?
Yes, they are metabolically active.
What is disinfection?
Disinfection is the process of eliminating or reducing harmful microorganisms from inanimate objects and surfaces.
What are the disadvantages of using UV radiation for sterilization?
It can damage skin and eyes and does not penetrate glass, cloth, and paper.
What is an example of a strict aerobe?
Pseudomonas.
How has microbiology changed during the last 3 decades?
Advancements in technology, genomics, and molecular biology have significantly enhanced our understanding and manipulation of microorganisms.
What type of organisms are made up of prokaryotic cells?
Bacteria and Archaea.
Are meiosis and mitosis present in Procaryotic cells?
No, both are absent.
What is the ribosome size in Eucaryotic cells?
80 S in the cytoplasmic reticulum.
Which disinfectants are effective against vegetative bacteria?
Alcohols, Hypochlorite, Iodine, Phenols
How do phenols act as disinfectants?
Phenols denature proteins and alter cell wall permeability.
What are the two factors that must be achieved throughout the load for complete sterilization?
Temperature and time.
What role does pH play in bacterial growth?
pH is a physical requirement that affects bacterial growth.
Why is osmotic pressure important for bacterial growth?
Osmotic pressure is a physical requirement that affects bacterial growth.
What characterizes the stationary phase of bacterial growth?
The rate of bacterial cell growth equals the rate of cell death, leading to a stable population size.
What is the periplasmic space in Gram-negative bacteria?
The periplasmic space is the area between the inner cytoplasmic membrane and the outer membrane in Gram-negative bacteria, containing enzymes and transport proteins.
Name a common method of sterilization.
Autoclaving, which uses steam under pressure to kill all microorganisms.
What is a common chemical used for disinfection?
Bleach (sodium hypochlorite) is a common chemical disinfectant.
What is the composition and function of the bacterial capsule?
The bacterial capsule is composed of polysaccharides. It prevents phagocytosis, contains K (capsular) antigens, aids in attachment, resists desiccation, and stores nutrients.
How would you disinfect human skin?
Using antiseptic agents such as alcohol or iodine.
What are pili (fimbriae) and their functions in bacteria?
Pili (fimbriae) are hair-like structures of protein. They aid in adherence to surfaces, resist phagocytosis, and contain F antigens.
How would you sterilize heat-sensitive sugars?
By filtration, as they cannot withstand high temperatures.
What are aerotolerant anaerobes?
Aerotolerant anaerobes are bacteria that do not require oxygen but can tolerate its presence.
What physical factors affect bacterial growth?
Osmotic pressure, pH, and temperature.
What is the chromosome topology in Eucaryotic cells?
Linear.
What are some trade names for hypochlorites?
Bleach, Clorox.
What special conditions are required for anaerobic bacteria to grow?
Special growth media and incubation conditions, such as a GasPak jar.
What are the common shapes and cell arrangements of bacteria?
Spheres, rods, and spirals.
Why is the number of contaminants important in disinfection?
A higher number of contaminants may require more disinfectant or longer exposure time to achieve effective disinfection.
How would you define bacteria?
Bacteria are single-celled microorganisms that can exist either as independent organisms or as parasites.
What did scientists study in the first half of the 20th century regarding microbes?
The structure, physiology, and genetics of microbes in detail.
What scientific fields extended insights to the molecular level by the end of the 20th century?
Molecular biology, genetics, genomics, and proteomics.
What are antiseptic agents?
Antiseptic agents are chemical substances that are applied to living tissues to inhibit or destroy microorganisms. Examples include iodine, alcohol, and chlorhexidine.
Do prokaryotic cells have a cell wall?
Yes, most prokaryotic cells have a cell wall.
What method is used for sterilization control of moist heat?
Using physical, chemical, and biological indicators.
Describe Koch's postulates. What is it about?
Koch's postulates are a set of criteria used to establish a causative relationship between a microbe and a disease. They include: 1) The microorganism must be found in all organisms suffering from the disease. 2) The microorganism must be isolated and grown in pure culture. 3) The cultured microorganism should cause disease when introduced into a healthy organism. 4) The microorganism must be re-isolated from the inoculated, diseased experimental host.
What class does Mycobacterium tuberculosis belong to?
Actinobacteria
What class does Escherichia coli belong to?
Gammaproteobacteria
What is the required time for sterilization at 160°C?
60 minutes.
Which disinfectants are effective against non-enveloped viruses?
Hypochlorite
What family does Escherichia coli belong to?
Enterobacteriaceae
What genus does Mycobacterium tuberculosis belong to?
Mycobacterium
What is the composition and function of the bacterial nucleoid?
The bacterial nucleoid is composed of a single, circular DNA molecule. Its function is to store genetic information and control cellular activities.
Which disinfectants are effective against fungi?
Alcohols, Hypochlorite, Iodine
What is the composition and function of the bacterial capsule?
The bacterial capsule is composed of polysaccharides or polypeptides. Its function is to protect the bacterial cell from desiccation and phagocytosis, and to aid in adherence to surfaces.
Do bacterial cells have organelles?
No, bacterial cells do not have organelles.
How would you disinfect the remaining blood or urine specimens?
Using chemical disinfectants like bleach or autoclaving if appropriate.
Why is nitrogen important for bacterial growth?
Nitrogen is a key component of amino acids, proteins, and nucleic acids, which are essential for bacterial growth and reproduction.
What is a microaerophile?
A microaerophile is a bacterium that requires oxygen at lower concentrations than are present in the atmosphere.
What is a risk associated with using chemical sterilants on instruments?
There is a risk of producing tissue damage if residual solution is carried over into the wound.
What is the optimal temperature range for psychrotrophs?
Psychrotrophs can grow at low temperatures but have an optimal range between 15°C and 30°C.
What is the mechanism of action of iodine compounds?
Iodine compounds denature proteins.
Why is the type and concentration of disinfectant important?
Different disinfectants have varying levels of effectiveness, and their concentration can determine how well they eliminate contaminants.
What is antisepsis?
The inhibition or elimination of microbes on skin or other living tissue.
To which phylum does Mycobacterium tuberculosis belong?
Actinobacteria
Which disinfectants are effective against mycobacteria?
Alcohols, Hypochlorite
What is the pore size range for filtration sterilization?
0.22-0.45 micrometers.
What types of radiation are used for sterilization?
Gamma and UV radiation.
What is the function of the outer membrane in Gram-negative bacteria?
The outer membrane in Gram-negative bacteria acts as a barrier to protect against harmful substances and contains lipopolysaccharides that can trigger immune responses.
Name two chemical elements essential for bacterial growth.
Nitrogen and Hydrogen.
How do bacteria reproduce?
Bacteria primarily reproduce through binary fission, a process where a single bacterial cell divides into two identical daughter cells.
What is binary fission?
Binary fission is a method of asexual reproduction in bacteria where a single cell divides into two identical daughter cells.
Which disinfectants have variable effectiveness against spores?
Hypochlorite
What is the composition and function of bacterial flagella?
Bacterial flagella are composed of the protein flagellin. Their function is to provide motility to the bacterial cell.
How would you make sure that the Autoclave works properly?
By using biological indicators such as spore tests to confirm that the autoclave reaches the necessary temperature and pressure to kill all microorganisms.
Do eukaryotic cells have organelles?
Yes, eukaryotic cells have organelles such as mitochondria.
What is the composition and function of bacterial inclusion bodies?
Bacterial inclusion bodies are composed of stored nutrients or building blocks, such as glycogen, polyphosphate, or sulfur. Their function is to store these materials for later use by the cell.
What is the composition and function of bacterial flagella?
Bacterial flagella are composed of flagellin (protein). They are responsible for motility and contain H (flagellar) antigens.
What are obligate aerobes?
Obligate aerobes are bacteria that require oxygen for their growth and survival.
What is a halophile?
A halophile is a bacterium that thrives in high-salt environments.
What leads to the death (decline) phase in bacterial growth?
Nutrient depletion and accumulation of toxic waste products cause the number of dying cells to exceed the number of new cells formed.
What are the two main types of metabolic processes in bacteria?
Catabolism and anabolism.
Name a chemical requirement for bacterial growth.
Carbon.
Do eukaryotic cells have a cell wall?
Some eukaryotic cells, such as plant cells and fungi, have a cell wall.
What are facultative anaerobes? Give an example.
Bacteria that can survive with or without oxygen. Example: Staphylococcus.
What are microaerophiles? Give an example.
Bacteria that require oxygen at lower concentrations than atmospheric levels. Example: Campylobacter.
Which disinfectants are effective against enveloped viruses?
Alcohols, Hypochlorite, Iodine, Phenols
To which order does Escherichia coli belong?
Enterobacteriales
What is an antiseptic?
An antiseptic is a substance that inhibits the growth and development of microorganisms on living tissues, such as skin.
Are sterols present in eukaryotic cells?
Yes, sterols are usually present in eukaryotic cells.
What is the composition and function of the bacterial cell membrane?
The bacterial cell membrane is composed of a phospholipid bilayer and proteins. It regulates permeability and transport.
How would you disinfect your workbench in the lab?
Using disinfectants such as ethanol or bleach.
How would you sterilize antibiotics?
By filtration, as antibiotics are heat-sensitive.
What is a mesosome and its function in bacteria?
A mesosome is a folded invagination in the plasma membrane that plays a role in cell wall formation and chromosome replication, increasing the surface area of the cell.
What does osmotolerant mean?
Osmotolerant bacteria can tolerate high osmotic pressure and can grow in environments with varying solute concentrations.
What questions did scientists begin to answer in the first half of the 20th century?
Questions relating to the links between specific microbial properties and disease.
List main points in the germ theory of disease.
The main points in the germ theory of disease are: 1) Microorganisms are the cause of many diseases. 2) These microorganisms can be transferred from one individual to another. 3) Specific diseases are caused by specific microorganisms.
What are the main components of the cell envelope in Gram-negative bacteria?
The cell envelope in Gram-negative bacteria consists of a thin peptidoglycan layer, an outer membrane containing lipopolysaccharides, and a periplasmic space.
What is the main genetic material in prokaryotic cells?
A single circular DNA molecule located in the nucleoid region.
What is the main genetic material in eukaryotic cells?
Multiple linear DNA molecules contained within a nucleus.
To which order does Mycobacterium tuberculosis belong?
Corynebacteriales
What is the required time for sterilization at 170°C?
45 minutes.
Which sterilization method is suitable for disposable gloves and plastic syringes?
Radiation (Gamma or UV).
Which disinfectants are not effective against spores?
Alcohols, Phenols
What genus does Escherichia coli belong to?
Escherichia
What is the composition of the bacterial cell wall and how does it differ between Gram-positive and Gram-negative bacteria?
The bacterial cell wall is composed of peptidoglycan. Gram-positive bacteria have a higher amount of peptidoglycan, while Gram-negative bacteria have a lower amount.
Which disinfectants have variable effectiveness against fungi?
Phenols
What is the mode of action of chlorine as a disinfectant?
Chlorine acts by oxidizing cellular components, leading to the destruction of microorganisms.
What are plasmids and their functions in bacteria?
Plasmids are extra-chromosomal circular DNA. R-Plasmids mediate antibiotic resistance, and F-Plasmids mediate DNA exchange.
What role does oxygen play in bacterial growth?
Oxygen is required by some bacteria for aerobic respiration, while others may be anaerobic and do not require oxygen.
How would you sterilize wire loops?
By flaming them until they are red hot.
What is sterilization?
Sterilization is the process of eliminating all forms of microbial life, including bacteria, viruses, spores, and fungi, from an object or surface.
What leads to the death (decline) phase in bacterial growth?
Nutrient depletion and accumulation of waste products cause the rate of cell death to exceed the rate of cell division.
Which disinfectants have limited effectiveness against non-enveloped viruses?
Iodine
What is the composition of the cell wall in bacteria?
Bacteria have a rigid layer of peptidoglycan in their cell walls, except in Mycoplasma.
What is a notable subspecies of Escherichia coli?
Enterotoxigenic E. coli
What is the composition and function of bacterial plasmids?
Bacterial plasmids are composed of small, circular DNA molecules. Their function is to carry genes that may provide a selective advantage, such as antibiotic resistance.
What are the two main types of requirements for bacterial growth?
Chemical requirements and physical requirements.
How would you sterilize media powder?
By autoclaving after it has been dissolved in water.
What are obligate anaerobes?
Obligate anaerobes are bacteria that cannot survive in the presence of oxygen.
What percentage of bacterium growth requirements are typically met by physical and chemical factors?
95%.
Which sterilization method is suitable for heat-sensitive materials like antibiotics and heat-sensitive sugars?
Filtration.
Why is sterilization important in healthcare settings?
Sterilization is crucial in healthcare settings to prevent infections and ensure that medical instruments and surfaces are free from all microorganisms.
What is the pore size for sterilizing a solution by filtration?
0.22 micrometers.
What is the purpose of using disinfectants in public spaces?
The purpose is to reduce the risk of spreading infectious diseases by eliminating or reducing pathogenic microorganisms on surfaces.
What are the components and functions of the bacterial cytoplasm?
The bacterial cytoplasm contains chromosomes, ribosomes, water, enzymes, and inclusion granules. It is involved in metabolic and catabolic activities.
Where is extrachromosomal DNA often found in bacterial cells?
Extrachromosomal DNA is often present in the form of plasmid(s) in bacterial cells.
What is the nucleoid in bacteria and its function?
The nucleoid is a circular molecule of DNA that contains the cell's genetic codes.
What are facultative anaerobes?
Facultative anaerobes are bacteria that can grow with or without oxygen, but generally grow better with oxygen.
Which sterilization method is suitable for metal trays and wire baskets?
Hot air oven.
What is the main difference between sterilization and disinfection?
Sterilization eliminates all forms of microbial life, while disinfection reduces or eliminates pathogenic microorganisms but may not kill all spores.
What are the physical methods of sterilization?
Methods that use physical agents such as heat, radiation, or filtration to achieve sterilization.
What is the composition of the cell wall in eukaryotic cells?
Eukaryotic cells do not have peptidoglycan in their cell walls.
What species does Escherichia coli belong to?
Escherichia coli
Are sterols present in bacterial cells?
No, sterols are absent in bacterial cells except in Mycoplasma.
What is the composition and function of the bacterial cytoplasm?
The bacterial cytoplasm is composed of water, enzymes, nutrients, wastes, and gases. Its function is to facilitate the chemical reactions necessary for the cell's metabolism and growth.
How does temperature affect bacterial growth?
Temperature affects the rate of bacterial metabolism and enzyme activity, with different bacteria having optimal growth temperatures.
What is an acidophile?
An acidophile is a bacterium that thrives in acidic environments with a low pH.
Which disinfectants have variable effectiveness against non-enveloped viruses?
Alcohols, Phenols
What family does Mycobacterium tuberculosis belong to?
Mycobacteriaceae
What is the required time for sterilization at 190°C?
7.5 minutes.
What is the composition and function of bacterial ribosomes?
Bacterial ribosomes are composed of RNA and proteins. Their function is to synthesize proteins by translating messenger RNA.
What is the difference between sterilization and disinfection?
Sterilization is the process of killing all forms of microbial life, including spores, while disinfection is the process of eliminating most pathogenic microorganisms, except bacterial spores.
Give an example of a physical method of sterilization.
Filtration, which removes microorganisms from liquids and gases by passing them through a filter.
What is the appropriate method to sterilize a substance containing bacterial spores?
Autoclaving, which uses steam under pressure to achieve high temperatures.
What is the composition and function of bacterial ribosomes?
Bacterial ribosomes are composed of protein and RNA. They are responsible for translation (protein synthesis).
How would you sterilize a glass Petri dish?
By autoclaving or using dry heat sterilization.
What are granules in bacteria and their function?
Granules in bacteria store nutrients such as phosphate, sulfur, and carbon.
What is a neutrophile?
A neutrophile is a bacterium that grows best at a neutral pH, typically around pH 7.
What is disinfection?
Disinfection is the process of reducing or eliminating pathogenic microorganisms on inanimate objects and surfaces, but it may not kill all spores.
What is the composition and function of the bacterial cell wall?
The bacterial cell wall is primarily composed of peptidoglycan. Its function is to provide structural support and shape to the cell, and to protect against osmotic pressure.
What is a distinctive feature of the cytoplasmic membrane in eukaryotic cells?
It is a semipermeable layer not possessing functions of the prokaryotic membrane.
What functions does the cytoplasmic membrane of bacteria have?
Contains enzymes of respiration, active secretion of enzymes, and is the site of phospholipid and DNA synthesis.
What species does Mycobacterium tuberculosis belong to?
Mycobacterium tuberculosis
What are the functions of the bacterial cell wall?
The bacterial cell wall protects from osmotic lysis and mediates interactions between the cell and its environment.
What is the composition and function of bacterial endospores?
Bacterial endospores are composed of a tough outer coating made of keratin-like proteins. Their function is to ensure the survival of the bacterium in harsh environmental conditions.
Where is extrachromosomal DNA found in eukaryotic cells?
Extrachromosomal DNA is found in organelles in eukaryotic cells.
Why is carbon important for bacterial growth?
Carbon is a fundamental element in organic molecules and is essential for the synthesis of cellular components.
How would you sterilize disposable syringes?
By using ethylene oxide gas or gamma irradiation.
What is the significance of pH in bacterial growth?
pH affects the enzyme activity and overall metabolism of bacteria, with different bacteria having optimal pH ranges for growth.
Which disinfectants have limited effectiveness against spores?
Iodine
What is the composition and function of bacterial pili?
Bacterial pili are composed of the protein pilin. Their function is to facilitate attachment to surfaces and to mediate conjugation (transfer of genetic material between bacteria).
Can disinfection be used on living tissues?
No, disinfection is typically used on inanimate objects and surfaces. Antiseptics are used on living tissues.
What is osmotic pressure in the context of bacterial growth?
Osmotic pressure refers to the pressure exerted by the solutes in a solution, which can affect the movement of water across bacterial cell membranes.
What are sex pili and their function in bacteria?
Sex pili are long hair-like structures of protein, also known as F or sex pilus. They are involved in the transfer of DNA during conjugation (sexual reproduction).
What is the significance of phosphorus in bacterial growth?
Phosphorus is a component of nucleic acids, ATP, and phospholipids, making it essential for energy transfer and cellular structure.
What is an alkalophile?
An alkalophile is a bacterium that thrives in alkaline environments with a high pH.