Comprehensive Microbiology: Diversity, Virology, Microbiome, Biotechnology, Infectious Disease, Immunology, and Therapeutics

Practice fill-in-the-blank flashcards covering eukaryotic diversity, virology, the microbiome, microbial biotechnology, infectious disease biology, immunology, antibiotics, and vaccines.

According to the endosymbiotic theory, mitochondria and chloroplasts originated from engulfed prokaryotes and contain their own circular naked DNA as well as ribosomes that are __________ in size.

$$70\text{S}$$

The branch of biology concerned with the systematic study of fungi is known as __________.

Mycology

The yeast genus __________ is the most common cause of fungal infections worldwide, responsible for yeast infections and other mycoses.

Candida

Unlike flagellates, ciliates, and amoeboid Sarcodina, the protozoan group known as sporozoans is entirely __________.

non-motile

The malaria parasite Plasmodium falciparum evades the host immune response by shuffling and changing its outer surface proteins during its lifetime in a process called __________.

antigenic variation

African Sleeping Sickness is caused by the flagellate protozoan Trypanosoma brucei and is transmitted to humans and other mammals by the bite of the __________.

tsetse fly

In the Toxoplasma gondii life cycle, feline species serve as the __________ host, shedding oocysts that take a minimum of $24\text{ hrs}$ to become infectious.

definitive

Flatworms known as __________ are considered the most damaging helminths to humans, infecting hundreds of millions of people worldwide and causing the chronic disease schistosomiasis.

blood flukes

Viruses lack independent metabolic machinery and can measure as small as __________ in size.

$$20\text{ nanometers}$$

The protein shell that encloses the viral genome is known as a(n) __________, which is constructed from individual protein subunits called capsomeres.

capsid

On complex bacteriophage capsids, the specialized appendages that recognize and physically attach to receptors on the host cell surface are called __________.

long tail fibers

In viral genomics, __________ ssRNA functions identically to mRNA and can be directly translated into viral proteins by host ribosomes upon cellular entry.

positive-sense

Because its genomic strand cannot be directly translated by host ribosomes, a negative-sense ssRNA virus must carry the enzyme __________ inside the virion to transcribe mRNA.

RNA-dependent RNA polymerase

In RNA retroviruses, synthesized proviral DNA is integrated into the host cell's nuclear chromosome by the viral enzyme __________.

integrase

During the lysogenic cycle of a bacteriophage, the phage genome integrated directly into the bacterial chromosome is termed a(n) __________.

prophage

The transition wherein an integrated prophage excises from the host bacterial genome to enter the active lytic cycle is called __________.

induction

A microorganism residing in or on the human body that neither benefits nor harms the human host is classified as a(n) __________.

commensal

The principle stating that established mutualistic and commensal gut microbes protect the host by competing for limited nutrients and cellular adhesion space is __________.

competitive exclusion

In the human gut, the harmless strains E. coli HS and E. coli Nissle together competitively exclude the toxin-producing foodborne strain __________ by consuming all five sugars it requires.

EDL933

A major component of human breast milk that provides no direct infant nutrition but selectively promotes intestinal colonization by Bifidobacterium longum infantis is __________.

human milk oligosaccharides

Recurrent gastrointestinal infections caused by antibiotic-resistant vegetative cells of Clostridium difficile can be treated by transferring donor stool via a procedure known as __________.

fecal microbiota transplant

The chronic periodontal pathogen __________ promotes elevated blood glucose levels by inhibiting host insulin receptors, linking chronic gum infection to type-II diabetes.

P. gingivalis

In molecular cloning, recombinant plasmids are generated by cleaving DNA with restriction enzymes and joining the target gene to the vector using the enzyme __________.

DNA ligase

The process by which bacterial cells are made competent—usually via heat shock—to take up recombinant plasmid DNA from their environment is called __________.

transformation

Discovered in 2016 in a recycling facility, the bacterium __________ produces the enzyme PETase, which degrades and metabolizes plastic.

Ideonella sakaiensis

Evaluating what genetic alterations cause a pathogen to acquire enhanced transmissibility, lethality, or drug resistance in a controlled laboratory setting is known as __________ research.

Gain-of-function

The Ames test identifies prospective carcinogens by measuring whether a chemical induces reversion mutations in a bacterial strain unable to synthesize the essential amino acid __________.

histidine

In the Ames test, rat __________ extract is combined with the suspected chemical to simulate the mammalian metabolic enzymes that may generate mutagenic by-products.

liver

The historical medical belief that human and animal diseases were caused by breathing foul, noxious vapor was known as the __________ theory.

miasma

In the 1840s, physician __________ showed that antiseptic hand cleansing prior to newborn deliveries significantly reduced maternal deaths from childbed fever.

Ignaz Philipp Semmelweis

The four experimental criteria formulated in 1890 to prove that a specific microorganism is the causal agent of a specific disease are known as __________.

Koch's postulates

In clinical diagnosis, a patient's subjective sensation such as pain or nausea is classified as a(n) __________, whereas an objectively measurable sign such as temperature or blood pressure is an observation.

symptom

In an infectious disease timeline, the interval from the initial moment of infection to the onset of infectious transmissibility is called the __________ period.

latent

The population-level metric and spectrum describing the severity of pathology or disease caused by an infection is referred to as infection __________.

virulence

The specific range of animal species that a pathogen is able to infect is termed its host __________.

tropism

A life-threatening condition caused by a dysregulated, overwhelming host immune response to an infection leading to organ dysfunction is termed __________.

sepsis

Any molecular structure on a pathogen that is recognized by the immune system and elicits an immune response is designated a(n) __________.

antigen

Immune signaling molecules secreted to facilitate cell-to-cell communication and recruit leukocytes toward an infection site are called __________.

cytokines

Phagocytic leukocytes recognize broadly conserved pathogen-associated molecular patterns (PAMPs) via innate surface receptors called __________.

Toll-like receptors

During phagocytosis, the membrane-bound vesicle enclosing the engulfed pathogen merges with a lysosome containing digestive enzymes to form a(n) __________.

phagolysosome

Constitutive granulocytes that represent $40\text{--}60\%$ of all circulating human white blood cells and act as rapid innate phagocytes are __________.

neutrophils

Innate immune granulocytes including basophils and mast cells release __________ to induce local vasodilation and enhance vascular permeability.

histamine

Granulocytic leukocytes whose primary immune function is attacking large multicellular parasites like helminths are __________.

eosinophils

Natural killer (NK) cells recognize healthy self-cells and withhold cytotoxic destruction when their inhibitory receptor binds to surface __________ molecules.

MHC I

Upon antigen encounter and activation in humoral immunity, naive B cells proliferate into memory cells and antibody-secreting effector cells called __________ cells.

plasma

In cell-mediated adaptive immunity, antigen-activated $\text{CD8}^+$ T cells differentiate into __________ T cells that directly destroy host cells harboring intracellular pathogens.

cytotoxic

Antibiotics that directly kill target bacteria are termed bactericidal, whereas those that inhibit bacterial cellular multiplication without killing are termed __________.

bacteriostatic

The property of an antibiotic to selectively harm or destroy bacterial pathogens without damaging host cells or tissues is called __________.

selective toxicity

In the Kirby-Bauer disk diffusion assay, the lowest concentration of an antimicrobial agent that halts the visible growth of a bacterium corresponds to the perimeter of the zone of inhibition and is known as the __________.

minimum inhibitory concentration

More than $90\%$ of horizontal gene transfer events spreading antibiotic-resistance genes among bacterial populations occur via direct cell-to-cell contact known as __________.

conjugation

The therapeutic administration of lytic bacteriophages to selectively infect and eradicate target bacterial infections is called __________.

phage therapy

A vaccine manufactured using an inactivated toxin produced by a bacterium or virus rather than the pathogen itself is classified as a(n) __________ vaccine.

toxoid