CORE Microbiology

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Questions and Answers

What is a characteristic change in the microbial population associated with metabolic disorders like obesity?

No change in microbial diversity

Decreased firmicutes and increased bacteroidetes

Increased diversity of microbial populations

Increased firmicutes and decreased bacteroidetes (correct)

Which of the following statements correctly describes Clostridium difficile infections?

They can lead to pseudomembranous colitis. (correct)

They are primarily Gram negative bacteria.

They cause infections that are harder to treat in an active state.

They are not associated with any gastrointestinal symptoms.

Which among the following is the treatment for Clostridium difficile infections?

Administration of antibiotics and nutritional supplements (correct)

Surgical intervention as the primary option

Antiviral medications

Increased intake of firmicutes-rich foods

What is a consequence of dysbiosis caused by Clostridium difficile?

Sepsis-like symptoms and potential death Signup and view all the answers

What role does the gut have in relation to the brain as mentioned in the content?

The gut influences brain activity and feelings. Signup and view all the answers

What type of bacteria was responsible for the Black Death?

Gram negative bacteria Signup and view all the answers

Which of the following is a characteristic used for diagnosing bacteria?

Morphology Signup and view all the answers

What defines a communicable disease?

A disease that spreads through direct contact between hosts Signup and view all the answers

Which statement about eukaryotic and prokaryotic mRNA is correct?

Prokaryotic mRNA can code for multiple proteins. Signup and view all the answers

Which type of disease is a result of microbial invasion or multiplication?

Infectious disease Signup and view all the answers

What is the significance of antimicrobial resistance (AMR) in the context of infectious diseases?

It complicates treatment options. Signup and view all the answers

Which of the following terms refers specifically to the study of the causes of disease?

Disease aetiology Signup and view all the answers

What term describes a microbe as the cause of a disease?

Microbial aetiology Signup and view all the answers

What type of microbiota is notably acquired at birth?

Lactobacillus Signup and view all the answers

Which of the following bacterial types is commonly found in the oral cavity?

Streptococcus Signup and view all the answers

What term describes the imbalance of types of organisms in the body?

Dysbiosis Signup and view all the answers

Which condition is associated with the Mycobiome and caused by Malasezzia furfur?

Pityriasis versicolor Signup and view all the answers

Which of the following is not associated with the GI tract?

Aspergillus Signup and view all the answers

What is the primary environment for the growth of Candida species?

Wet and moist Signup and view all the answers

In which location would you find Lactobacillus instead of Prevotella?

Vagina Signup and view all the answers

What is one of the most common forms of inflammatory bowel disease (IBD)?

Crohn's disease Signup and view all the answers

Which type of microbial is predominantly found in dry environments?

Aspergillus Signup and view all the answers

Which microbial balance indicates a potential health issue?

Dysbiosis Signup and view all the answers

What is the primary function of the bacterial capsule?

Providing immune resistance Signup and view all the answers

Which characteristic distinguishes Gram positive and Gram negative bacteria in terms of their cell wall structure?

Gram positive has a thick peptidoglycan wall Signup and view all the answers

What role does fimbriae play in bacterial cells?

Attachment to surfaces Signup and view all the answers

What is the defining structural component of fungi's cell wall?

Chitin Signup and view all the answers

What is true regarding the classification of viruses?

Based on disease vectors and location Signup and view all the answers

What common structural feature do Gram negative bacteria possess that Gram positive do not?

Multiple membranes Signup and view all the answers

Which type of bacteria are pili specifically associated with?

Only Gram negative Signup and view all the answers

Which statement correctly describes the life cycle of a virus?

It relies on the host's cell machinery. Signup and view all the answers

What does the term 'virion' refer to in virology?

The ineffective form of the virus Signup and view all the answers

What factor limits the growth of fungi when comparing it to bacteria?

Lower pH levels Signup and view all the answers

What phase of bacterial growth occurs when adaptation to the environment is complete and optimal conditions for growth are present?

Log phase Signup and view all the answers

Which type of medium allows for the growth of a wide array of bacteria?

General growth medium Signup and view all the answers

What is the primary role of microbiota in the human body?

Contributing to immune development Signup and view all the answers

Which of the following statements about anaerobes is correct?

Anaerobes do not require oxygen for growth. Signup and view all the answers

How does the microbiota contribute to the maintenance of pH in the body?

By fermenting sugars Signup and view all the answers

What aspect of bacterial growth phases is represented by the stationary phase?

Toxic product accumulation Signup and view all the answers

What is the estimated proportion of body weight that microbiota constitutes?

1-3% Signup and view all the answers

Which bacteria are often found in dry areas of the human body?

Staphylococcus epidermidis Signup and view all the answers

What characteristic distinguishes the death phase of bacterial growth?

Toxin levels and nutrient depletion lead to cell death. Signup and view all the answers

What is a significant effect of microbiota on human health?

Stimulates immune system maturation Signup and view all the answers

Study Notes

Microbiology

Microbiology is the study of microorganisms, including bacteria, archaea, viruses, fungi, and protozoa.
Prokaryotic pathogens include bacteria.
Eukaryotic pathogens include fungi, protozoa, and parasitic worms.
Infectious diseases are a leading cause of death, and Antimicrobial Resistance (AMR) is a critical concern.

Prokaryotic & Eukaryotic Pathogens

Pathogenesis is the origination and development of a disease.
Molecular pathogenesis studies molecules involved in disease.
Microbial pathogenesis is the ability of microbes to cause infection.
Host-pathogen interaction describes how microbes survive in hosts.
Disease etiology studies the causes of diseases, while microbial etiology specifically looks at microbes as causes.
Microbial diseases are illnesses caused by microorganisms.
Infectious diseases are illnesses caused by microbial invasion.
Communicable diseases are ones that spread among hosts.
Contagious diseases are easily spread between hosts.

Prokaryotes vs. Eukaryotes

Prokaryotes (bacteria & archaea) are simple, single-celled organisms without a nucleus or membrane-bound organelles.
Eukaryotes (animals, plants, fungi, and protists) are complex, single-celled or multicellular organisms with a nucleus and membrane-bound organelles.
Key structural differences include cell size, membrane composition, ribosome structure, DNA organization, presence of organelles, and cell wall structure.
Bacterial shape categories include bacilli, cocci, ovococci, spirillum, spirochaetes, and vibrio.
Bacterial arrangement categories include strepto, staphylo, diplococci.
Prokaryotes have polycistronic gene expression, meaning one mRNA molecule can code for multiple proteins, whereas eukaryotes have monocistronic gene expression, where one mRNA molecule codes for a single protein.
Eukaryotic mRNAs are shorter, which affects protein-coding capacities.
Prokaryotic genomes are usually more compact, and eukaryotes tend to have larger, more complex genomes.
Eukaryotes have introns in their genes (non-coding sections), not present in prokaryotes. Exons are the coding regions.

Bacterial Structures

Capsules are polysaccharide layers that aid in immune resistance and moisture absorption.
Cell walls determine bacterial shape. They are composed of sugars linked by amino acids.
Flagella allow movement (motility).
Fimbriae are short, filamentous proteins that promote bacterial attachment to surfaces.
Pili are longer, hollow structures involved in cell interactions and genetic exchange.

Viruses

Viruses are acellular entities with limited metabolic capabilities. They depend on host cells for replication.
Viral structure often involves an outer protein capsid surrounding genetic material (DNA/RNA).
Viral shapes include helical and icosahedral symmetries.

Ecological Relations

Microbes can form beneficial, detrimental, and commensal relationships with their hosts.
Beneficial relationships include mutualistic interactions.
Detrimental relationships include parasitic and pathogenic interactions.

Fungi

Fungi are eukaryotes that reproduce through binary fission and as hyphae.
Their cell walls are made of chitin.
They require a lower pH than bacteria to grow.

Protozoa

Protozoa are single-celled eukaryotes, often categorized by how they move (pseudopodia, flagella, cilia).
They are found in diverse environments and some cause infection.

The Human Microbiota

The human microbiota is the collection of microorganisms living in and on the human body.
Significant microbial communities exist in several body parts (mouth, gut, skin).
Microbiota are beneficial for diverse factors, influencing immune development, nutrient production, and antimicrobial production.
Their numbers and types vary based on factors such as diet, age, and environment.
Dysbiosis is an imbalance within beneficial and pathogenic communities, which can lead to disease conditions in the human body.
Several factors can potentially disrupt a balance or potentially predispose dysbiosis, including antibiotics, aging, changes in the nutrition, environment, or host immune status.

Bacterial Growth Phases

Bacterial growth is observed in four phases: lag phase, log phase, stationary phase, and death phase.
The optimal conditions vary across bacterial species.

Classification

Gram-positive bacteria are stained different colors from gram-negative bacteria depending on their cell wall structure (thick vs. thin peptidoglycan layer).
Bacteria are classified and identified by various methods, including their shape, arrangement, metabolic characteristics, and genetic makeup.
Different types of media/environments can be used for bacterial growth and differential differentiation.

Diagnostics

Diagnosis of bacterial, fungal, and viral infections commonly relies on observations of shape and arrangements of microbes as part of microscopy and other more highly specialized testings for diagnostics.
Biochemical properties.
Detailed genetic makeup (specific gene sequences).

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Description

Test your knowledge of microbiology with this quiz focusing on prokaryotic and eukaryotic pathogens. Explore concepts such as pathogenesis, microbial diseases, and the role of microorganisms in infectious diseases. Understand the significance of antimicrobial resistance and host-pathogen interactions.