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Questions and Answers
What is the primary method by which most bacteria multiply?
What is the primary method by which most bacteria multiply?
Which of the following bacterial shapes is characterized as being twisted?
Which of the following bacterial shapes is characterized as being twisted?
What term describes cocci that remain in pairs after cell division?
What term describes cocci that remain in pairs after cell division?
What characteristic distinguishes bacilli from cocci regarding their grouping after division?
What characteristic distinguishes bacilli from cocci regarding their grouping after division?
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Which of the following terms refers to a group of cocci that remain together in grape-like clusters?
Which of the following terms refers to a group of cocci that remain together in grape-like clusters?
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Which of the following best describes the classification of bacteria based on their nutritional requirements?
Which of the following best describes the classification of bacteria based on their nutritional requirements?
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What term is used to describe bacteria that can assume several different shapes?
What term is used to describe bacteria that can assume several different shapes?
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Which size range is typical for most bacteria?
Which size range is typical for most bacteria?
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What clinical findings are associated with group B streptococcal infection during the first month of life?
What clinical findings are associated with group B streptococcal infection during the first month of life?
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How does intravenous ampicillin help mothers who carry group B streptococcus?
How does intravenous ampicillin help mothers who carry group B streptococcus?
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Which of the following describe Streptococcus pneumoniae?
Which of the following describe Streptococcus pneumoniae?
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What is the most common urinary tract infection-causing organism?
What is the most common urinary tract infection-causing organism?
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What is a common symptom of Shigella infection?
What is a common symptom of Shigella infection?
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Which of the following correctly describes Vibrios?
Which of the following correctly describes Vibrios?
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What is the primary pathogenic characteristic of Vibrio cholerae?
What is the primary pathogenic characteristic of Vibrio cholerae?
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What symptoms might indicate E. coli's association with diarrheal diseases?
What symptoms might indicate E. coli's association with diarrheal diseases?
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What is the primary mode of transmission for Treponema pallidum?
What is the primary mode of transmission for Treponema pallidum?
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What is a characteristic symptom of cholera infection?
What is a characteristic symptom of cholera infection?
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What happens to the mortality rate of cholera without treatment?
What happens to the mortality rate of cholera without treatment?
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Which of the following is a feature of Treponema pallidum?
Which of the following is a feature of Treponema pallidum?
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What is the incubation period for syphilis caused by Treponema pallidum?
What is the incubation period for syphilis caused by Treponema pallidum?
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Which type of lesion develops at the site of Treponema pallidum infection?
Which type of lesion develops at the site of Treponema pallidum infection?
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What characterizes the primary lesion in Treponema pallidum infection?
What characterizes the primary lesion in Treponema pallidum infection?
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Which condition increases susceptibility to Vibrio cholerae infection?
Which condition increases susceptibility to Vibrio cholerae infection?
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What is the primary function of flagella in bacteria?
What is the primary function of flagella in bacteria?
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Leptospirae typically grow best under which conditions?
Leptospirae typically grow best under which conditions?
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Which of the following is NOT a type of cell surface appendage in bacteria?
Which of the following is NOT a type of cell surface appendage in bacteria?
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What is one symptom of leptospirosis during its biphasic illness?
What is one symptom of leptospirosis during its biphasic illness?
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How do leptospirae typically enter the human body?
How do leptospirae typically enter the human body?
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What laboratory test can be performed to diagnose leptospirosis?
What laboratory test can be performed to diagnose leptospirosis?
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What is the structure of leptospirae as seen under a microscope?
What is the structure of leptospirae as seen under a microscope?
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What is the incubation period for leptospirosis?
What is the incubation period for leptospirosis?
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What is the primary function of pili in bacteria?
What is the primary function of pili in bacteria?
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Inclusion bodies in bacteria typically consist of what substances?
Inclusion bodies in bacteria typically consist of what substances?
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What distinguishes differential staining from simple staining?
What distinguishes differential staining from simple staining?
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Which of the following is a characteristic feature of Gram-negative bacteria?
Which of the following is a characteristic feature of Gram-negative bacteria?
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What is typically stored in the form of polyhydroxyalkanoates or glycogen in bacteria?
What is typically stored in the form of polyhydroxyalkanoates or glycogen in bacteria?
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Which of the following stains is commonly used in simple staining procedures?
Which of the following stains is commonly used in simple staining procedures?
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What information can be gathered from a WBC differential test?
What information can be gathered from a WBC differential test?
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What is commonly associated with sulfur granules in bacteria?
What is commonly associated with sulfur granules in bacteria?
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Study Notes
Bacteria
- Bacteria are single-celled organisms that multiply by binary fission
- Bacteria can be differentiated by their morphology, chemical composition, nutritional requirements, biochemical activities, and source of energy
Size, shape, and arrangement of bacteria cells
- Most bacteria are 0.2 um in diameter and 2-8 um in length
- The three basic bacterial shapes are coccus (spherical), bacillus (rod-shaped), and spiral (twisted)
- Pleomorphic bacteria can assume several shapes
- Cocci that remain in pairs after dividing are called diplococci
- Cocci that divide in multiple planes and form grape-like clusters or sheets are called staphylococci
- Cocci that remain in chains after dividing are called streptococci
- Cocci that divide in two planes and remain in groups of four are called tetrads
- Most bacilli appear as single rods
- Diplobacilli appear in pairs
- Streptobacilli appear in chains after division
- Some bacilli are so short and fat that they look like cocci and are referred to as coccobacilli
- Spiral bacteria have one or more twists
- Vibrios look like curved rods
- Spirilla have a helical shape and fairly rigid bodies
Appendages of bacteria
- Appendages are proteinaceous tubular or fibrous structures found on the surface of bacterial cells
- Appendages extend from the surface of the bacterial cell wall
- Appendages have many functions including locomotion, attachment, adhesion, and assisting in genetic exchange
Types of appendages
- Flagella are the most important for locomotion and can also act as a sensory organ
- Fimbriae are bristle-like short fibres that enable bacterial cells to stick to the surface of host cells and help form pellicles or biofilms
- Pili are long hair-like tubular microfibres found on the surface of some Gram-negative bacteria
Inclusions of bacteria
- Inclusion bodies are nuclear or cytoplasmic aggregates of stainable substances, usually proteins
- Inclusion bodies typically represent sites of viral multiplication in a bacterium or eukaryotic cell and usually consist of viral capsid proteins
- Researchers have recovered folded protein from inclusion bodies
- Many bacteria store excess carbon in the form of polyhydroxyalkanoates or glycogen
Distinguishing features of stains
- Simple stains involve only one stain
- Basic stains, such as methylene blue, Gram safranin, or Gram crystal violet are useful for staining most bacteria
Differential stains
- Differential stains use more than one chemical stain
- Differential stains help differentiate between different microorganisms or structures/cellular components of a single organism
- Differential staining is used to detect abnormalities in the proportion of different white blood cells in the blood and is useful because many diseases alter the proportion of certain white blood cells
- Gram staining is a differential stain that uses two dyes: Crystal violet and Fuschsin or Safranin to differentiate between Gram-positive bacteria and Gram-negative bacteria.
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Description
Test your knowledge on bacteria, their shapes, and reproduction methods. This quiz covers various types of bacteria including cocci, bacilli, and their arrangements. Dive into the fascinating world of microbiology and enhance your understanding of these essential organisms.
