148 Questions
What is the primary factor contributing to the rapid evolution of prokaryotes?
Rapid reproduction
Which process involves the transfer of genetic material between prokaryotic cells in direct contact?
Conjugation
What is the term for the combination of DNA from two sources?
Genetic recombination
Which type of prokaryote obtains energy from light?
Phototroph
What is the term for the movement of genes among individuals from different species?
Horizontal gene transfer
Which process involves the uptake and incorporation of foreign DNA by prokaryotic cells from their surroundings?
Transformation
What is the term for the exchange of DNA between bacteria mediated by bacteriophages?
Transduction
Which type of prokaryote requires an organic nutrient as a carbon source?
Heterotroph
What is the main component of Gram-positive bacteria cell walls?
Peptidoglycan
What is the result of Gram staining in Gram-negative bacteria?
Pink color
What is the function of the peptidoglycan layer in Gram-positive bacteria?
To provide structural support and maintain the cell's shape
Which of the following bacteria is an example of Gram-positive bacteria?
Staphylococci
What is the composition of the outer membrane in Gram-negative bacteria?
Lipopolysaccharides and sugars
What is the difference between Gram-positive and Gram-negative bacteria in terms of resistance to lysozyme?
Gram-positive bacteria are sensitive to lysozyme, while Gram-negative bacteria are resistant
What is the space between the inner and outer membrane in Gram-negative bacteria called?
Periplasm
What is the result of Gram staining in Gram-positive bacteria?
Purple color
What is the alternative structure used by Flexibacter polymorphus instead of flagella?
Polysaccharide fibers
Which of the following phospholipids is NOT present in the plasma membrane of prokaryotic cells?
Phosphatidyl-choline
What is the function of mesosomes in some prokaryotes?
Cellular respiration
Which of the following is a characteristic of the plasma membrane of prokaryotic cells?
It is selectively permeable
What is the main difference between prokaryotic and eukaryotic cells in terms of internal organization?
Prokaryotic cells lack complex compartmentalization
What is the movement of genes among individuals from different species called?
Horizontal gene transfer
Which of the following lipids is NOT present in the plasma membrane of hepatocytes?
Phosphatidyl-glycerol
What is the primary function of the plasma membrane in cells?
To regulate what enters and leaves the cell
Which bacterium is a potential weapon of bioterrorism?
Bacillus anthracis
Which of the following is a type of lipid found in the plasma membrane of myelin?
Cerebrosides
What is the causative agent of pneumococcal meningitis?
Streptococcus pneumoniae
What is the name of the methicillin-resistant strain of Staphylococcus aureus?
MRSA
Which bacterium causes gonococcal urethritis?
Neisseria gonorrhoeae
What is the characteristic of Streptococcal colonies?
They form chains
Which disease is characterized by chronic cough with blood-containing sputum?
Tuberculosis
What is the bacterium that causes leprosy?
Mycobacterium leprae
Which type of bacteria lacks a cell wall?
Mycoplasmas
What is the function of botulinum toxin?
Inhibits the release of the neurotransmitter acetylcholine
Which bacterium is the source of many antibiotics?
Streptomyces
What is the cause of tetanus?
Clostridium tetani
What is the result of respiratory muscle failure due to botulism?
Death
Which type of bacteria is Gram-Positive?
Actinomycetes
What is the name of the disease caused by Bacillus anthracis?
Anthrax
What is the result of improper canning of food contaminated with Clostridium botulinum?
Botulism
What is the primary function of prokaryotic ribosomes?
Protein synthesis
What is the characteristic of prokaryotic chromosomes?
Circular, double-stranded DNA
What is the function of plasmids in prokaryotes?
Carrying genes for antibiotic resistance
What is the name of the region that contains the prokaryotic chromosome?
Nucleoid
What is the term for the ability of some prokaryotes to form endospores?
Sporogenic
What is the difference between prokaryotic and eukaryotic ribosomes?
30S and 50S subunits vs 40S and 60S subunits
What is the function of mesosomes in some prokaryotes?
Not mentioned in the text
What is the shape of prokaryotic chromosomes?
Circular
What is the primary mechanism of transmission of tetanus?
Through a break in the skin by a contaminated object
What is the characteristic feature of Corynebacterium diptheriae?
Formation of pseudomembranes in the pharynx and trachea
What is the unique feature of the cell wall of Mycobacteria?
It has a lipid-rich outer layer
What is the primary function of diphtheria toxin?
To inhibit protein synthesis
What is the characteristic symptom of tetanus?
Convulsive muscle spasms
What is the distinguishing feature of Mycoplasmas?
They lack a cell wall
Which of the following bacteria is associated with non-gonococcal urethritis?
Ureaplasma urealyticum
Why are Mycobacteria classified as acid-fast Gram-positive bacteria?
Because they lack an outer LPS layer
What is the common characteristic among the organisms classified under Domain Bacteria and Domain Archaea?
They are unicellular prokaryotes
What is the characteristic that defines the members of Kingdom Fungi?
They absorb nutrients after decomposing organic material
Which of the following kingdoms consists of multicellular eukaryotes that carry out photosynthesis?
Kingdom Plantae
What is the characteristic of the organisms classified under Domain Eukarya?
They are multicellular eukaryotes
In which type of environment do Domain Archaea organisms typically live?
Extreme environments
What is the number of kingdoms that Domain Eukarya is divided into?
4
What is the characteristic of Protists?
They are unicellular eukaryotes
Which of the following is NOT a characteristic of Domain Bacteria?
They are multicellular eukaryotes
What is the characteristic of endospores that allows them to survive in harsh environments?
Resistance to temperature, dryness, UV light, enzymes, chemicals, and drugs
What is the main advantage of prokaryotes' short generation times?
It allows them to adapt to changing environments
What is the result of the process of binary fission in prokaryotes?
Two identical daughter cells
Which bacterium is an example of a sporogenic bacterium?
Bacillus anthracis
What is the function of the cortex in endospore structure?
Resistance to high temperature
What is the characteristic of prokaryotic reproduction that allows for rapid evolution?
Short generation times
What is the result of cell plate formation in prokaryotic cell division?
Formation of a new cell wall
What is the term for the process of prokaryotic cell division that results in two identical daughter cells?
Binary fission
What is the primary function of the capsule in some prokaryotes?
Protects bacteria from phagocytosis/digestion/drying
Which bacterium is used in gene cloning to produce transgenic plants?
Agrobacterium tumefaciens
What is the disease caused by Vibrio cholerae?
Cholera
What is the bacterium that causes Syphilis?
Treponema pallidum
Which bacterium can produce vitamins, antibiotics, and hormones?
Bacteria
What is the disease caused by Neisseria meningitidis?
Meningococcal meningitis
What is the function of flagella in some prokaryotes?
Provides motility to the bacteria
Which bacterium causes Gastritis, stomach ulcers, and gastric cancer?
Helicobacter pylori
What is the characteristic of prokaryotic ribosomes that allows some antibiotics to target them without affecting human ribosomes?
They consist of different subunits than eukaryotic ribosomes
What is the primary function of thylakoid membranes in photosynthetic prokaryotes?
Photosynthesis
What is the term for the viruses that infect bacteria and have a DNA genome?
Bacteriophages
What is the characteristic of prokaryotic chromosomes that allows them to fit within the nucleoid region?
They are supercoiled
What is the function of polysomes in prokaryotes?
Protein synthesis
What is the characteristic of endospores that allows them to survive in harsh environments?
They are highly durable
What is the primary function of mesosomes in some prokaryotes?
Cellular respiration or photosynthesis
What is the characteristic of the plasma membrane in prokaryotic cells?
Selectively permeable
What is the alternative structure used by Flexibacter polymorphus instead of flagella?
Polysaccharide fibers
Which of the following lipids is present in the plasma membrane of prokaryotic cells?
Phosphatidyl-glycerol
What is the characteristic of prokaryotic cells in terms of compartmentalization?
They lack complex compartmentalization
What is the function of the plasma membrane in cells?
Regulation of what enters and leaves the cell
Which of the following bacteria causes syphilis?
Treponema pallidum
What is unique about cyanobacteria?
They are photoautotrophs
What is the result of scarring of the fallopian tubes due to Chlamydia trachomatis infection?
Infertility
Which of the following Gram-positive bacteria causes diphtheria?
Corynebacterium diphtheriae
What is the mode of transmission of Leptospira?
Direct contact with infected animals
Which of the following bacteria is associated with non-gonococcal urethritis?
Chlamydia trachomatis
What is the main characteristic of micro-organisms?
They consist of either 1 cell or a group of cells
Which of the following is NOT a category of micro-organisms?
Animals
What was the discovery of Alexander Fleming in 1929?
The antibiotic penicillin
What is the primary characteristic of pathogenic bacteria species?
They are potential weapons of bioterrorism
What is the name of the disease caused by the Yersinia pestis bacterium?
Plague
What is the primary function of Staphylococcus aureus?
It causes toxic shock syndrome, food poisoning, and pneumonia
What is the term for the 40-day duration that Venetian ships coming from countries with active plague epidemics remained under quarantine in the sea?
Quarantine
What is the primary characteristic of Mycobacterium tuberculosis?
It causes tuberculosis
What is the primary function of Neisseria gonorrhoeae?
It causes gonococcal urethritis
What is the characteristic of prokaryotes that allows them to thrive almost everywhere?
Their ability to live under extreme conditions
What is the name of the domain that includes non-pathogenic bacteria that perform photosynthesis?
Cyanobacteria
What is the primary characteristic of Horizontal gene transfer?
It involves the movement of genes among individuals from different species
What is the primary function of Bacillus cereus?
It causes food poisoning
What is the system of naming living organisms invented by Carolus Linnaeus?
Binomial nomenclature
What is the shape of prokaryotic cells?
Variable morphology
What is the name of the disease caused by the HIV virus?
AIDS
What is a characteristic of Domain Eukarya?
Multicellular eukaryotes
In which type of environment are Archaea typically found?
Extreme environments
What is the basis for defining Kingdom Fungi?
Mode of nutrition
What is a characteristic of protists?
Unicellular and simple multicellular eukaryotes
How many kingdoms are included in Domain Eukarya?
4
What is the characteristic of bacteria that allows them to be divided into multiple kingdoms?
Diversity and widespread distribution
What is the main component of the cell wall in Gram-positive bacteria?
Peptidoglycan
What is the function of the peptidoglycan layer in Gram-positive bacteria?
To provide resistance to physical stress
Which of the following is an example of Gram-negative bacteria?
Escherichia coli
What is the function of the outer lipopolysaccharide layer in Gram-negative bacteria?
To provide resistance to lysozyme and penicillin
What is the result of Gram-staining in Gram-positive bacteria?
Purple colour
What is the difference between the cell wall structure of Gram-positive and Gram-negative bacteria?
Gram-positive bacteria have a larger amount of peptidoglycan
What is the characteristic of archaea that distinguishes them from bacteria?
Their shared traits with eukaryotes
Which type of prokaryotes are poisoned by oxygen and use fermentation or anaerobic respiration?
Obligate anaerobes
What is the term for the process of converting atmospheric nitrogen (N2) to ammonia (NH3) by some prokaryotes?
Nitrogen fixation
Which method has been used to investigate the phylogeny of prokaryotes?
Molecular systematics
What is the environment in which extreme thermophiles thrive?
Very hot environments
What is the term for the study of evolutionary relationships among groups of organisms using molecular sequencing data and morphological data?
Phylogenic taxonomy
What is the role of prokaryotes in the biosphere with regard to chemical elements?
They increase the availability of nitrogen, phosphorus, and potassium for plant growth.
What is the type of symbiotic relationship where one organism benefits while the other is not affected?
Commensalism
What is the primary mechanism by which pathogenic prokaryotes cause disease?
By releasing toxins
What is the term for the ecological relationship where two species live in close contact?
Symbiosis
What is the role of beneficial prokaryotes in the human body?
They break down undigested food in the intestines
What is the process by which genes associated with virulence can be spread among bacteria?
Horizontal gene transfer
What is the term for the 40-day duration that Venetian ships coming from countries with active plague epidemics remained under quarantine in the sea before they approached Venice port?
Quarantina giorni
Which of the following micro-organisms are eukaryotic?
Protists
What is the main advantage of micro-organisms' ability to replicate quickly?
They can evolve quickly
Which of the following pandemics was caused by the Yersinia pestis bacterium?
Black Death
What is the term for the classification of living organisms?
Taxonomy
Which of the following is NOT a characteristic of prokaryotes?
Eukaryotic
What is the term for the system of naming living organisms invented by Carolus Linnaeus?
Binomial nomenclature
Which of the following is a type of micro-organism that is not cellular?
Viruses
What is the term for the ability of some prokaryotes to form endospores?
Sporulation
Which of the following is a characteristic of Domain Archaea?
Molecular similarities with eukaryotes
Study Notes
Prokaryotic Cell Structure
- Prokaryotic cells have a cell wall that provides protection and maintenance of cell shape
- The cell wall is composed of peptidoglycan (Gram-positive) or peptidoglycan and lipopolysaccharides (Gram-negative)
Gram-Positive and Gram-Negative Bacteria
- Gram-positive bacteria:
- Cell wall composed of peptidoglycan
- Absorb crystal violet and appear purple
- Examples: Staphylococcus, Streptococcus, Micrococcus
- Gram-negative bacteria:
- Cell wall composed of peptidoglycan and lipopolysaccharides
- Do not absorb crystal violet and appear pink
- Examples: Escherichia coli, Shigella, Salmonella
Plasma Membrane
- Composed of phospholipids and proteins
- Selectively permeable (semi-permeable)
- Lipid composition varies between different membranes
Internal Organization and DNA
- Prokaryotic cells lack complex compartmentalization
- No membrane-bound nucleus or membrane-bound organelles
- Mesosomes: infoldings of the plasma membrane that perform metabolic functions
- Prokaryotic chromosome: a double-stranded circular DNA molecule
- Smaller than eukaryotic genome
- Absence of histones
- Supercoiled to fit the nucleoid region
Reproduction and Adaptation
- Prokaryotes reproduce quickly by binary fission
- Short generation times allow for rapid evolution
- Adaptation: development of antibiotic resistance
Pathogenic Bacteria
- Examples of pathogenic bacteria: Neisseria meningitidis, Neisseria gonorrhoeae, Escherichia coli, Salmonella, Legionella, Vibrio cholerae
- Causes of diseases: meningococcal meningitis, gonococcal urethritis, opportunistic infections, legionellosis, cholera
Prokaryotic Ribosomes
- Function: protein synthesis
- Consist of different subunits than eukaryotes
- Some antibiotics inhibit bacterial ribosomes without inhibiting human ribosomes
Nucleoid
- Region that contains the prokaryotic chromosome
- Not surrounded by a nuclear membrane
Endospores
- Formed under harsh conditions
- Metabolically inactive
- Remain viable in harsh conditions for years
- Resistant to temperature, dryness, UV light, enzymes, chemicals, and drugs
Sporogenic Bacteria
- Examples: Bacillus, Clostridium
- Ability to form endospores
Prokaryotic Cell Division
- Binary fission
- Short generation times
- Adaptation: development of antibiotic resistance### Horizontal Gene Transfer and Pathogenic Bacteria
- Horizontal gene transfer: movement of genes among individuals from different species
- Pathogenic bacteria:
- Examples: Bacillus anthracis, Staphylococcus aureus, Streptococcus pneumoniae, Bacillus cereus, Neisseria meningitidis, Neisseria gonorrhoeae, Escherichia coli, Mycobacterium tuberculosis, Mycobacterium leprae
- Can cause diseases such as toxic shock syndrome, food poisoning, pneumonia, meningitis, and tuberculosis
Prokaryotes and Microorganisms
- Prokaryotes:
- Unicellular microorganisms
- Consist of 1 prokaryotic cell
- Replicate faster than eukaryotes
- Smaller in size than eukaryotic cells
- Divided into 2 domains: Bacteria and Archaea
- Can thrive in extreme conditions
- Microorganisms:
- Microscopic organisms consisting of 1 cell (unicellular) or a group of cells (multicellular)
- Categories: Bacteria, Archaea, Protists, Fungi, and Viruses
Historical Evidence and Pandemics
- Historical evidence for the existence of microorganisms:
- Pathogenic microorganisms cause infectious diseases
- Examples: plague, cholera, and smallpox
- Pandemics:
- Viral and bacterial outbreaks throughout history
- Examples: Antonine plague, Justinian plague, Black Death, and COVID-19
Prokaryote Characteristics and Taxonomy
- Prokaryote characteristics:
- Smaller in size than eukaryotic cells
- Variable morphology
- Can thrive in extreme conditions
- Taxonomy:
- Classification of living organisms
- Species, Genus, Family, Order, Class, Phylum, Kingdom, and Domain
- Nomenclature of microorganisms: binomial system (e.g., Staphylococcus aureus)
Bacteria and Archaea
- Bacteria:
- 2 major categories: Eubacteria and Cyanobacteria
- Eubacteria: includes pathogenic bacteria
- Cyanobacteria: non-pathogenic, photosynthetic, and produce oxygen
- Archaea:
- Live in extreme conditions
- Examples: Halophiles, Methanogens, and Thermoacidophiles
- Initially named Archaebacteria due to morphological similarities with Bacteria
Structural and Functional Properties
- Prokaryotic cell size: 1-10 µm
- Variable morphology: spherical, rod-shaped, and spiral shapes
- Oxygen metabolism: obligate aerobes, obligate anaerobes, and facultative anaerobes
- Nitrogen metabolism: nitrogen fixation, conversion of nitrogen into ammonia
Test your knowledge of Gram-positive and Gram-negative bacteria, their cell walls, and the Gram staining process. Learn about the differences in their peptidoglycan and lipopolysaccharide composition. Identify the characteristics of each type of bacteria and how they react to crystal violet.
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