Microbial Genetics and Genomics Quiz

Reproduction where two organisms combine their DNA to create offspring with varied genetic material.

Reproduction where one organism creates an offspring with identical genetic material.

The transfer of genetic material between different organisms, without being passed down through generations.

A horizontal gene transfer method where bacteria take up free DNA from the environment.

A horizontal gene transfer method where DNA is transferred between bacteria by a virus.

A type of viral-mediated gene transfer where a specific piece of bacterial DNA is packaged within a phage and transferred to a new bacterial cell. This transfer often depends on the phage's integration site in the bacterial chromosome.

A protein appendage, also known as the F pilus, that extends from a bacterial cell and allows for direct contact with another bacterium, facilitating the transfer of genetic material during conjugation.

A bacterial cell where the F plasmid has integrated into the bacterial chromosome. This integration allows for the transfer of chromosomal genes during conjugation, leading to high frequency of recombination.

A type of transduction where random bacterial DNA fragments are packaged within phage particles and transferred to new bacterial cells. This occurs when a phage accidentally packages bacterial DNA instead of its own.

A cluster of genes in a bacterial chromosome that have a distinct origin from the rest of the genome. These islands often encode specialized functions like pathogenicity or antibiotic resistance.

A defense mechanism in the respiratory system that sweeps foreign particles, including microbes, out of the lungs and back through the mouth.

The epithelial cells of alveoli have various ways to defend themselves against microbes, including surfactant with antimicrobial properties, mucus secretion, alveolar macrophages, and dendritic cells.

The urogenital tract has a specific microbial community that varies depending on location and factors like pH and hormones. The vagina, for example, is usually acidic due to lactic acid produced by bacteria, while the bladder and kidneys are typically sterile.

The skin microbiome is influenced by its diverse microhabitats, including dry, acidic epidermis and oily, anaerobic dermis. This environment favors gram-positive bacteria due to their resistance to salt and dryness.

The gut microbiota plays crucial roles in digestion, immune system development, and overall health. It aids in breaking down complex carbohydrates, producing short-chain fatty acids, and preventing pathogens from colonizing.

For an infection to occur, a pathogen must be exposed to a host, adhere to the host's surface, invade through the epithelial barrier, grow and multiply, and cause damage to tissues.

Glycoproteins or lipoproteins on a bacterial cell wall that recognize and bind to host cell receptors, enabling attachment.

A polysaccharide coat that surrounds bacteria, preventing phagocytosis by hiding them from immune cells.

An enzyme produced by bacteria that breaks down hyaluronic acid, a substance that holds cells together, facilitating tissue invasion.

A virulence factor that directly injects bacterial proteins from the bacterial cytoplasm into the host cell upon contact.

The variety of different types of bacteria living in the gut. A diverse microbiome is generally healthier, as it promotes competition and prevents harmful bacteria from dominating.

An imbalance in the gut microbiota, where the proportion of harmful bacteria increases, leading to potential health problems.

Fiber acts as fuel for beneficial bacteria, promoting their growth and outcompeting harmful bacteria. It also increases gut motility, preventing harmful bacteria from sticking to the gut wall and causing infections. Additionally, it stimulates the production of SCFAs, which promote immune system health and reduce inflammation.

Short-chain fatty acids (SCFAs) are produced by gut bacteria when they ferment fiber. They have various health benefits, including promoting satiety, reducing inflammation, strengthening the gut barrier, and enhancing immune function.

Living microorganisms, like bacteria or yeast, that are intentionally ingested to improve gut health by restoring a healthy balance of bacteria.

Pathogens that have been engulfed by phagocytes can avoid digestion and continue to thrive within the host cell. This involves various strategies like preventing lysosome fusion, escaping the phagosome, or mimicking host signals to disrupt immune responses.

A strategy used by pathogens to avoid digestion inside a phagosome. They resist breakdown, multiply, and form visible aggregates within the host cell.

Infection refers to the presence and growth of microbes in a host, whether they are causing symptoms or not. Disease occurs when the infection leads to noticeable symptoms and harm.

Bacteremia is the presence of bacteria in the bloodstream, often transient and harmless. Septicemia is a systemic blood infection with a massive immune response, leading to potentially fatal septic shock.

The severity of the disease caused by a pathogen. It encompasses how easily a pathogen can cause infection (infectivity), the severity of the disease (virulence) and the genetic makeup.

The lethal dose 50. The amount of a pathogen needed to kill 50% of a test group of animals.

Exotoxins are proteins secreted by bacteria, often highly toxic. Endotoxins are components of bacterial cell walls, mainly LPS in gram-negative bacteria. Both can cause harm but through different mechanisms.

A type of exotoxin that targets and destroys cells. Often acts by disrupting cell membranes, leading to cell death.

Bacteria come in three main shapes: rods (bacilli), spheres (cocci), and spiral (spirochetes).

The glycocalyx, a capsule or slime layer, helps bacteria stick to surfaces, resist phagocytosis, and survive dehydration.

Gram-positive bacteria have a thick peptidoglycan layer that retains crystal violet dye, appearing purple. Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane, retaining safranin dye, appearing pink.

Acid-fast bacteria have a waxy outer coating of mycolic acid, making them resistant to staining and harder for the immune system to recognize.

The bacterial plasma membrane acts as a barrier, anchors proteins, and generates energy through ATP synthases. It also contains lipids that help bacteria adapt to different temperatures.

The bacterial cytoskeleton, composed of proteins like FtsZ, MreB, and Crescentin, helps maintain cell shape, organize cell division, and move molecules throughout the cell.

Endospores are dormant, resistant structures formed by some bacteria when conditions are unfavorable. They contain DNA, dipicolonic acid, and other protective layers, allowing them to survive harsh environments.

Passing genetic material from one generation to the next, like a mother cell to a daughter cell.

Transferring small pieces of DNA between different organisms, even distantly related ones.

A type of horizontal gene transfer where bacteria share genetic material directly through a pilus.

A type of viral-mediated gene transfer where a specific piece of bacterial DNA is packaged within a phage and transferred to a new bacterial cell. This transfer often depends on the phage's integration site in the bacterial chromosome.

The transfer of genetic material between bacteria through direct cell-cell contact using a conjugation pilus.

A bacterial cell where the F plasmid has integrated into the bacterial chromosome. This integration allows for the transfer of chromosomal genes during conjugation, leading to high frequency of recombination.

A type of transduction where random bacterial DNA fragments are packaged within phage particles and transferred to new bacterial cells. This occurs when a phage accidentally packages bacterial DNA instead of its own.

A cluster of genes in a bacterial chromosome that have a distinct origin from the rest of the genome. These islands often encode specialized functions like pathogenicity or antibiotic resistance.

For an infection to develop, a pathogen must be exposed to a host, adhere to the host's surface, invade through the epithelial barrier, multiply and grow within the host, and cause damage to host tissues.

Commensal bacteria in the gut play vital roles in human health, including digestion of complex carbohydrates, production of short-chain fatty acids that provide energy, preventing pathogenic bacteria from colonizing, and contributing to immune system development through tolerance and inflammation regulation.

The composition of gut microbiota evolves throughout life and is influenced by factors like diet, age, and physiology. For example, breastfed infants have different gut microbiota from formula-fed infants, and a high-fiber diet promotes diverse microbial communities.

Gut microbiota plays crucial roles in maintaining health and well-being. It acts as a source of energy by breaking down complex carbohydrates humans can't digest, forms a protective barrier against microbial invasion, assists in immune system development, and contributes to vitamin biosynthesis and digestion of chemical compounds.

A high-fiber diet with diverse fiber types promotes a healthy gut microbiome. It provides food for beneficial bacteria, increases gut motility, and stimulates production of beneficial short-chain fatty acids (SCFAs).

Dysbiosis refers to an imbalance in the gut microbiota, where the number of harmful bacteria increases relative to beneficial bacteria. This can lead to various health problems.

Pathogens can disrupt the balance of the gut microbiota by outcompeting beneficial bacteria for resources and space. This can happen due to factors like antibiotic use, poor diet, and weakened immune system.

Short-chain fatty acids (SCFAs) produced by gut bacteria can influence obesity. Some SCFAs, like acetate, may promote obesity, while others, like butyrate, may have anti-obesity effects. The ratio of SCFAs can impact energy metabolism and inflammation.

Probiotics are live microorganisms, like bacteria, that are intentionally introduced into the gut to restore a healthy balance. Prebiotics are non-digestible fibers that act as food for beneficial bacteria, promoting their growth.

A structured community of bacteria attached to a surface, often enclosed in a slimy matrix, providing a protective environment for bacteria.