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Despite being called the reverse citric acid cycle, it is currently identified as the most ancient autotrophic pathway. Although the sulfate-reducing bacteria are thought to be critical in the corrosion of metal structures, the mechanism of metal corrosion is not […]

Which process produces a gaseous product that can be used as fuel to provide heat or power for a wastewater treatment plant? A) trickling filter secondary wastewater treatment B) aerobic secondary wastewater treatment C) anaerobic secondary wastewater treatment D) primary […]

Which of the following is NOT an accomplishment of Louis Pasteur? A) determined that the alcohol-making process was mediated by microbial fermentation and thus refuted the theory of spontaneous generation B) developed enrichment culture techniques C) developed heat sterilization techniques […]

Two eukaryotic organelles that are hypothesized to be the result of endosymbiosis are the ________ and the ________. A) nucleus / Golgi body B) mitochondrion / chloroplast C) endoplasmic reticulum / Golgi body D) hydrogenosome / chloroplast To determine viable […]

At present there are four phyla in the domain Bacteria. Transposons can be found on many genetic elements, including plasmids, chromosomes, and viral genomes. Answer: TRUE Both hydrophilic and charged molecules readily diffuse through the cytoplasmic membrane. Answer: FALSE The […]

Bacteria that are capable of oxidizing both iron and sulfur usually have a strong preference for sulfur oxidation because it yields more energy. Rhodobacter and Roseobacter are two genera with a common ancestor in Alphaproteobacteria. Answer: TRUE Th17 cells are […]

With increased levels of oxidizable materials, the biochemical oxygen demand (BOD) will A) increase. B) decrease. C) remain the same. D) increase or decrease depending on the nature of the materials involved. Stable isotope probing (SIP) is a method that […]

The single most important physical sign of primary syphilis is A) the chancre. B) a skin rash. C) paralysis. D) an acute eye infection. Coccolithophores and foraminiferans both use ________ to form their exoskeletons. A) Si4+ B) Fe3+ C) Ca2+ […]

The arrangement of Class II MHC proteins in pairs or trimers enhances their stability. Several fluorogenic dyes can be used simultaneously in a sample as long as they each emit light at a different measurable wavelength. Answer: TRUE The proton […]

The rickettsias can be cultured in A) pure culture. B) artificial media. C) laboratory animals. D) pure culture, artificial media, and laboratory animals. Which of the following are NOT substrates for methanogens? A) acetate and pyruvate B) carbon dioxide, carbon […]

The number of Vibrio cholera cells necessary to produce cholera in an exposed individual is drastically reduced if the individual is malnourished. Gut symbionts are lost after each molting a termite undergoes. Answer: TRUE In antigen binding, MHC protein binds […]

Reconstructing evolutionary relationships helps in differentiating between primitive and derived characteristics. Th2 cells produce a cytokine that promotes growth and activation of other T cells and activates macrophages. Answer: FALSE Poly-β-hydroxybutyric acid (PHB) is a carbon- and energy-storing polymer. Answer: […]

Staphylococcus aureus and Streptococcus pyogenes produce exotoxins known as superantigens that bind to a site on the TCR that is outside the antigen-specific TCR binding site. Acidic foods generally need a higher canning temperature than do nonacidic foods. Answer: FALSE […]

Immunization against endemic diseases is NOT necessary when traveling outside of one’s home country or region. Tetanus is highly contagious through person-to-person contact. Answer: FALSE Magnesium is not considered a growth factor for microorganisms, because growth factors are always organic […]

Which of the following sequences would be cleaved by a type II restriction endonuclease? A) TTGCCGA AACGGCT B) GGGGGGG CCCCCCCC C) GTAATG CATTAC D) GAATTC CTTAAG Restriction is A) the viral process whereby a host’s DNA ceases normal functioning. B) […]

The entire complement of RNA produced under a given set of conditions is called a(n) A) array. B) genome. C) proteome. D) transcriptome. Aseptic technique refers to A) the microbial inoculum placed into a test tube or onto a Petri […]

Type II restriction endonucleases A) are heterodimers. B) natively function to methylate specific nucleotides and prevent foreign DNA from being incorporated into the genome. C) recognize nucleotide sequences that are palindromic. D) require ATP energy to cleave dsDNA. Bacteria in […]

FISH technology can employ only a single phylogenetic probe. Thermoplasma grows either aerobically or anaerobically by sulfur respiration. Answer: TRUE The domains of life arose as barriers between gene exchange evolved between organisms. Answer: TRUE Two organisms containing identical GC […]

When does endospore formation commence? A) when bacterial growth ceases due to limitation of an essential nutrient B) when the bacterium is undergoing binary fission C) when bacteria are dividing exponentially D) following bacterial death To verify a gene was […]

The death phase applies to individual cells rather than populations. Nitrogenases not only reduce N2 but also can act on acetylene (C2H2). Answer: TRUE All TLR can react with only one specific PAMP. Answer: FALSE TCRs recognize epitopes only after […]

Louis Pasteur developed the vaccine(s) for A) anthrax. B) fowl cholera. C) rabies. D) anthrax, fowl cholera, and rabies. Which is most abundant and active in divisome complexes? A) FtsZ B) DNA replication forks C) MinCD D) MreB Answer: D […]

Molecular sequencing suggests that mitochondria arose from a group of prokaryotic organisms within the A) Crenarchaeota. B) cyanobacteria. C) iron-oxidizing bacteria. D) Proteobacteria. You are given an electron micrograph of a bacterial cell. In the micrograph you can clearly see […]

The hyperthermophilic members of the Crenarchaeota branch very close to the root of the universal tree. Oligotrophic organisms do NOT grow well under nutrient-replete conditions. Answer: TRUE The primary domains were founded based on comparative ribosomal RNA gene sequencing. Answer: […]

Cyclic 2,3-diphosphoglycerate (cDPG) is present in molar quantities in the cytoplasm of many hyperthermophilic methanogens. The function of this compound is to A) prevent rRNA misfolding. B) prevent chemical damage to DNA at high temperatures. C) counteract the effects of […]

Bacteria found in the mouth in the first years of life are well-adapted to biofilm formation. Due to a chemical equilibrium, a syntrophic relationship can be disrupted if the product from the first partner’s metabolism is removed too quickly. Answer: […]

The inflammatory cytokines IL-1, IL-6, and TNF-α are also A) opsonizing agents that coat foreign cells. B) activating cytokines that stimulate Th1 cells to replicate. C) capable of producing systemic fever by stimulating the release of prostaglandins in the brain. […]

The bacterium Escherichia coli comprises a significant fraction of the bacterial population in healthy adult humans, ranging from 10-50%. The lag phase does NOT occur if all the cells in the culture are viable. Answer: FALSE Functional differences can be […]

Archaea have a unique form of conjugation involving cytoplasmic bridges for bidirectional transfer of DNA. What is the main form of nitrogen found on Earth? A) N2 B) NO C) NO3– D) NH4 Answer: A You want to know whether […]

A disease that is present in unusually high numbers throughout the world is called a(n) A) endemic. B) epidemic. C) sporadic. D) pandemic. Cholera is an example of a pandemic disease that A) has multiple wild animal reservoirs and is […]

In natural samples it is often difficult to differentiate live cells from dead cells or cells from nonliving matter. Metabolism is a unifying characteristic of all cellular organisms. Answer: TRUE The purpose of the enrichment culture technique is to enrich […]

Some of the intestinal symptoms elicited by pathogens such as Salmonella, Shigella, and Escherichia are due to the presence of A) pseudomurein. B) S-layers. C) lipopolysaccharides. D) peptidoglycan. Genes from different sources that are related in sequence due to shared […]

Reverse transcriptase is a(n) A) RNA-dependent DNA polymerase. B) DNA-dependent DNA polymerase. C) RNA-dependent RNA polymerase. D) DNA-dependent RNA polymerase. The primer for retrovirus reverse transcription is a specific A) tRNA encoded by the cell. B) tRNA encoded by the […]

A chemoorganotroph and a photoautotroph in the same environment would NOT compete for A) oxygen. B) carbon. C) nitrogen. D) carbon and oxygen. The goal of tertiary wastewater treatment is to sharply reduce the levels of ________ from the final […]

Gram-negative bacteria are responsible for causing MOST foodborne diseases. RNA acts at both the genetic and the functional levels. Answer: TRUE Thermoplasma metabolizes organic compounds leached from hot coal refuse. Answer: TRUE Rabies infection in humans leads to symptoms a […]

Genome assembly relies on A) accurate gene annotation. B) overlap of a large numbers of short sequences. C) codon bias. D) systems biology. The science that applies powerful computational tools to DNA and protein sequences for the purpose of analyzing, […]

Diseases can be controlled through immunization even if the percentage of the population that is immunized is less than 100% because A) vectors can be controlled through other means. B) most diseases lack reservoirs. C) of herd immunity. D) vehicles […]

While not all members of ________ are pathogenic, two medically relevant species cause meningitis and gonorrhea in humans. A) Enterobacter B) Neisseria C) Shigella. D) Staphylococcus Antibodies are found in A) milk. B) mucosal secretions. C) serum. D) milk, mucosal […]

The incidence of HIV among hemophiliacs and transfusion recipients has remained constant since 1994. Some virulence genes are carried on plasmids or lysogenic bacteriophages. Answer: TRUE Except that they are not produced in the cytoplasm, conidia produced by Streptomyces spp. […]

An individual can receive injections of an antiserum or purified antibodies derived from an immune individual. Depending on the particular metabolism of a bacterium, electron transport can be used to energize and rotate ATP synthase. Answer: FALSE Bacteria that degrade […]

Fungi are the main contributor to the biodeterioration of stone building materials and concrete wastewater distribution systems. Knowledge of an organism’s genome sequence yields important clues to how an organism functions and its evolutionary history. Answer: TRUE UV radiation is […]

Legionella pneumophila is generally transmitted by A) contaminated food. B) contaminated drinking water. C) contaminated water in coolers, pools, and domestic water systems. D) personto-person contact. Chemolithotrophy involves A) oxidation of organic compounds. B) oxidation of inorganic compounds. C) reduction […]

Differential selection and reproduction of phenotypes occurs during a process called A) cellular differentiation. B) evolution. C) growth. D) transformation. Transfer RNA molecules A) function to transfer ribonucleotides to RNA polymerase during transcription. B) function to transfer the correct amino […]

Anthrax is an emerging disease for which there is no treatment or vaccine available. Genomics analysis of recently isolated viruses indicate some viruses contain larger genomes than the some bacterial genomes. Answer: TRUE During elongation of a cell during binary […]

The amino acid composition of thermostable proteins is not particularly unusual, except for a bias for increased levels of amino acids that form α-helices. Both environmental conditions and nutrient resources strongly influence the composition of a microbial community. Answer: TRUE […]

Which of the following statements is TRUE? A) Lambda is a temperate phage that infects Escherichia coli. B) Lambda is a linear double-stranded DNA phage. C) Lambda is replicated by the rolling circle mechanism. D) Lambda is a temperate phage […]

A disease showing a relatively slow, progressive rise followed by a gradual decline in incidence is indicative of a(n) A) host-to-host epidemic. B) common source epidemic. C) biological weapon. D) endemic disease. When dealing with stable isotopes, enzymes tend to […]

Single-cell genomics may help us A) predict which microbes will be abundant based on the environmental conditions. B) understand the physiology of uncultured microbes. C) develop better enrichment culture methods. D) understand the physiology of uncultured microbes and develop better […]

The chlorophytes use both chlorophylls a and b for photosynthesis, which make them appear green. One important advantage of eukaryotic cells as hosts for cloning vectors is that they already possess the complex RNA and posttranslational processing systems required for […]