35 Questions
What is the main focus of the learning objectives in the Introduction to Microorganisms course?
Demonstrating knowledge of medically important microbial pathogens
Which of the following is NOT included in the medically important microbial pathogens discussed in the course?
Protists
What is the primary function of SANITATION (INFRASTRUCTURE) in preventing illnesses transmitted by water, food, and direct contact?
Preventing exposure to microbial pathogens
What is a significant limitation of VACCINATION in preventing infections?
Constraints due to research and development (R&D)
What is the size of E. coli in terms of diameter and length, as mentioned in the text?
~1µm diameter, 2µm length
What is the basic genetic material found in bacteria?
Double stranded DNA organized into a circular chromosome
Which immune evasion strategy involves the modification of surface antigens?
Run
What is the primary mechanism of action of bacterial toxins that damage membranes?
Cleave host surface components
Which organism causes severe watery diarrhea and is characterized by G- curved rod morphology?
Vibrio cholerae
What is the primary treatment for the disease caused by Vibrio cholerae?
Oral rehydration
Which virulence/pathogenesis feature of Vibrio cholerae makes children/adults in developing countries at risk?
Cholera toxin
In what way does molecular mimicry contribute to autoimmune disorders?
Confusing the immune system to attack self-tissues
Which of the following components is typical of bacteria?
Cell wall with peptidoglycan
What is the approximate size range of viruses?
20-300nm
Which organism is an obligate intracellular parasite?
Protozoa
What is a defining characteristic of fungi?
Cell wall made of peptidoglycan
What distinguishes prions from other pathogens?
Infectious proteins
Which microorganism has the ability to form spores?
Bacteria
Which type of cells have 80S ribosomes?
Fungal cells
Which organism is characterized by the presence of a defined nucleus and other organelles?
Protozoa
What distinguishes bacterial colony morphology?
Growth characteristics including colony size, shape, and color
What distinguishes the replication process of fungi?
Budding
What is the primary determinant of infectious disease outcome according to current thinking?
Status of host immunity and virulence properties of the pathogen
Which step in the Infectious Cycle of Most Pathogens involves increasing bacterial numbers?
Replication/Colonization
What is the most common portal of entry for Bordetella pertussis?
Respiratory tract
What is the main function of bacterial capsules?
Prevent phagocytosis by PMN
Which term describes a collection of aggregated bacteria bound to a surface and embedded in a self-produced polymeric matrix?
Biofilm
How do bacteria within biofilms respond to antimicrobial agents?
They become inherently resistant to antimicrobial agents
What is the mechanism of antigenic variation for Neisseria gonorrhoeae pilin?
Homologous recombination between expressed and silent loci
What is the main function of antigenic variation for Neisseria gonorrhoeae pilin?
Evade the immune system
Which strategy is used by bacteria to evade the immune system by producing or decorating their cell surface with host-like proteins?
Molecular mimicry
What contributes to the dissemination of bacteria within the host?
Local inflammation causing damage
"Twitching motility" in bacteria is pilus-mediated and allows them to move along which type of surfaces?
"Solid surface" translocation surfaces
What does the main function of a biofilm prevent?
Prevent phagocytosis by PMN.
What is the major function of bacterial flagella?
Contribute to bacterial motility.
Study Notes
- The text is about microorganisms and includes information on learning objectives, prevention of microbial infections, and characteristics of various types of microorganisms.
- Learning objectives include demonstrating knowledge of microbial pathogens, their morphology, structure, genetics, growth characteristics, and host-pathogen interactions.
- Microorganisms include bacteria, viruses, fungi, parasites, and prions, which can cause illnesses transmitted through water, food, or direct contact.
- Prevention strategies include sanitation, vaccination, and antibiotics. Sanitation is the biggest impact prevention method and prevents transmission via water, food, and direct contact. Vaccination prevents infection in exposed individuals, but its impact is limited by research and development. Antibiotics cure infections, but they are losing effectiveness due to the size of microorganisms and the presence of drug targets.
- Microorganisms range in size, with E. coli being around 1µm in diameter and 2µm in length. Prokaryotes, such as bacteria, have a circular chromosome and possess a cell wall. They are frequently drug targets and can be classified using taxonomic ranks.
- Viruses are infectious particles containing either DNA or RNA and are incapable of propagation outside a living cell. They can take a variety of forms and have a significant impact on human health. Fungi are eukaryotic cells that possess a defined nucleus and a cell wall. They can be unicellular (yeasts) or filamentous (molds) and have complex lifestyles.
- Prions are noncellular, infectious proteins that can cause neurological diseases by converting normal proteins into abnormal ones. They result in microscopic sponge-like holes that damage and destroy neurons.
- Characteristics of medically important microbial pathogens include their mode of transmission, morphology, structure, basic genetics, and growth characteristics. They can be strict or opportunistic pathogens and can cause a range of diseases.
- The study of microbial pathogens is important for understanding diseases and developing prevention and treatment strategies.
- To prevent microbial infections, it is essential to understand the microorganisms, their modes of transmission, and prevention strategies like sanitation, vaccination, and antibiotics.
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