Microbiology Quiz on Bacterial Functions

Specialized bacterial proteins that bind to host cell receptors, initiating the attachment process. They like to stick to surfaces!

A type of adhesin that binds to extracellular matrix proteins like fibronectin and collagen, allowing bacteria to adhere to host tissues.

A protein produced by Staphylococcus aureus that binds to host IgG antibodies, disrupting immune defenses like opsonization and phagocytosis.

Bacterial proteins that allow bacteria to invade host cells, often by triggering their uptake. They know how to barge in!

An enzyme that breaks down hyaluronic acid, a component of the extracellular matrix, allowing bacteria to penetrate tissues and spread.

An enzyme that breaks down collagen, a major protein in connective tissues, facilitating bacterial invasion and spread.

An enzyme that converts plasminogen to plasmin, a fibrin-dissolving enzyme that allows bacteria to escape clots and spread through the bloodstream.

Structured communities of bacteria encased in a self-produced matrix, resistant to antibiotics and immune responses. Think of it as a bacterial fortress.

Short-chain fatty acids (SCFAs) produced by gut bacteria through fermentation of dietary fibers, such as acetate, propionate, and butyrate.

SCFAs have anti-inflammatory effects by influencing immune cells to produce anti-inflammatory cytokines and suppress pro-inflammatory responses. Butyrate, in particular, inhibits histone deacetylases which contributes to reducing inflammation.

SCFAs can enter the bloodstream and influence organs like the liver, impacting lipid metabolism, glucose homeostasis, and insulin sensitivity.

Gut bacteria break down undigested carbohydrates, proteins, and peptides into gases and organic acids during fermentation.

Fermentation produces gases like hydrogen, carbon dioxide, and methane. These gases influence gut motility and contribute to the gut's microbial community structure.

Certain gut bacteria degrade amino acids into byproducts like indole, ammonia, and hydrogen sulfide. High levels of these can be toxic to the gut.

Primary bile acids produced in the liver are modified by gut bacteria into secondary bile acids, like deoxycholic acid.

Bile acids are important for fat digestion, acting like detergents to emulsify fats and enhance absorption. Secondary bile acids also prevent the overgrowth of harmful bacteria in the gut.

Enzymes that break down the beta-lactam ring, a critical structure in penicillin, cephalosporin, and carbapenem antibiotics, rendering them ineffective.

A specific type of Beta-lactamase that can break down third-generation cephalosporins, often leading to resistance to broad-spectrum antibiotics.

A group of Beta-lactamases that use zinc to break down carbapenems, a powerful class of antibiotics.

Also known as AmpC beta-lactamases. They can resist a broad range of beta-lactam antibiotics.

These enzymes add specific chemical groups (acetyl, phosphate, or adenyl) to aminoglycosides, making them unable to bind to their target, preventing them from stopping bacterial protein synthesis.

An enzyme that adds an acetyl group to chloramphenicol, a common antibiotic, making it unable to reach its target and stop bacterial protein synthesis.

The ability of a bacterial cell to resist an antimicrobial agent even before exposure to it.

The development of resistance to an antimicrobial agent after initial sensitivity.

Genetic elements that can capture and express genes, particularly resistance genes, through site-specific recombination. This process is mediated by an integrase enzyme.

Large DNA segments acquired through horizontal gene transfer that often carry clusters of resistance genes. These islands are integrated into the bacterial chromosome and may be associated with virulence factors.

Random changes in the DNA sequence of bacteria can lead to resistance. For example, mutations in the rpoB gene can alter the binding site on RNA polymerase, making the bacteria resistant to rifampin.

Under selective pressure, like antibiotic exposure, resistant bacteria survive and reproduce more easily. This leads to an increase in resistant strains within a population over time.

Bacteria use various mechanisms to fight against antimicrobial agents, such as degrading the antibiotic, modifying its target, expelling it, reducing its entry, forming a protective layer, and acquiring resistance genes from other bacteria. These mechanisms help bacteria survive and thrive in the presence of antibiotics.

The global challenge of antimicrobial resistance (AMR) arises from bacteria being able to resist antibiotics, leading to difficult-to-treat infections. Understanding these mechanisms is crucial for developing new strategies to combat bacterial infections and curb the spread of resistance.

Viruses that infect bacteria and can be used in research and therapy.

Viruses that infect archaea, a type of microorganism distinct from bacteria.

Viruses spread through respiratory droplets or aerosols.

Viruses transmitted by insects or other vectors.

Viruses spread through contaminated food or water.

Viruses spread through blood and bodily fluids.

Viruses transmitted from animals to humans.

Viral genomes can be either DNA or RNA, single or double-stranded. This is a key basis for classifying viruses.

These viruses use host cells to create a complementary strand of DNA, which allows them to replicate.

Parvoviruses are known for causing Fifth disease in children and can infect animals. They are an example of single-stranded DNA viruses.

Circoviruses infect pigs and birds. They have a unique circular structure in their DNA genome.

Positive-sense RNA viruses use their RNA directly as mRNA to produce proteins, allowing for immediate replication after entering a host cell.

These viruses cause a range of diseases, including polio and the common cold. They belong to the positive-sense single-stranded RNA virus family.

Coronaviruses, like SARS-CoV-2 (that caused the COVID-19 pandemic), are categorized as positive-sense single-stranded RNA viruses. They have a distinguishable spike protein that enables them to enter host cells.

These viruses are known to cause serious diseases like dengue and West Nile fever. They are primarily spread by mosquitoes. They fall under the positive-sense single-stranded RNA virus family.

Negative-sense RNA viruses use their RNA as a template to create a positive-sense RNA strand, which then acts as mRNA for protein production.