Microbial Pathogenicity
If a patient accidentally ingests Streptococcus pneumoniae via heavily contaminated food and it safely transits into the gastrointestinal tract, the person will inevitably develop severe bacterial pneumonia.
False
An extracellular, infectious viral particle that exists completely outside of a host cell is structurally referred to as a virion.
True
The concept of taxonomy consists of three interrelated parts: classification, nomenclature, and _______________.
Identification
Members of the phylum Actinobacteria typically possess genomic DNA with a high GC content.
True
Organisms that live together in an anatomical habitat where one partner derives clear metabolic or environmental benefits while the host partner is completely unharmed and unaffected are engaging in a specific type of symbiotic relationship known as?
Commensalism
Yellow fever, Dengue fever, Chikungunya, and Zika are distinct viral pathogens grouped together epidemiologically because they are all categorized as animal-transmitted zoonoses passed via direct mammalian bites.
False
In prokaryotic genotypic classification, organisms whose genomes are at least ______% homologous are generally considered to belong to the same species.
70%
The phylum Proteobacteria is composed entirely of gram-positive bacteria and represents the third largest class of bacterial diversity.
False
In the clinical progression of an infectious disease, what is the specific stage called when the pathogen begins multiplying at high levels, becomes well-established, and the patient's clinical signs and symptoms shift from vague discomfort to highly specific, diagnostic indicators?
Period of invasion
While some viral genomes consist of double-stranded DNA or single-stranded RNA, the specialized group of viruses that copy their single-stranded RNA genome into a double-stranded DNA intermediate during replication are known as?
Retroviruses
In numerical taxonomy, when calculating the degree of similarity between two organisms, the coefficient that completely ignores any characters that both organisms lack is known as the _______________.
Jaccard coefficient (Sj)
In the domain Archaea, a key common trait across all phyla is the presence of peptidoglycan in their cell walls.
False
During a clinical study on a patient with a severe intestinal infection, doctors decide to use a fecal transplant instead of standard broad-spectrum antibiotic therapy. Based on ecological principles of the gut microflora, explain the functional goal of this treatment.
To reintroduce a normal, healthy microbiota community to actively colonize the gut, become established, and exclude the disease-causing pathogen.
In a bacterial host cell infected by a temperate bacteriophage, the latent or integrated viral genome that replicates in synchrony with the host’s chromosome without causing immediate lysis is specifically called a __________.
Prophage
Bacterial DNA with a higher G + C (guanine and cytosine) content will separate into single strands at a lower melting temperature (Tm) than DNA with a lower G + C content because they contain fewer hydrogen bonds.
False
Within the phylum Euryarchaeota, methanogens and extreme halophiles share identical ecological niches because both groups function as strict, obligate anaerobes.
False (They represent physiological contrasts: methanogens are strict anaerobes, whereas extreme halophiles are primarily obligate aerobes)
A clinical pharmacologist uncovers a bacterial toxin that is highly heat-stable, acts as an integral component of the cell wall, and causes a non-specific systemic drop in blood pressure. Based on these distinct biochemical traits, what specific category of toxin is this, and which group of bacteria produces it?
Endotoxin (or Lipopolysaccharide / Lipid A); produced exclusively by Gram-negative bacteria.
Briefly describe the specific mechanical functions performed by the tail fibers, base plate, and tail pins during the initial replication stages of a complex virus like Bacteriophage T4.
These tail components function collectively to anchor or attach the virion onto the surface of the specific host cell and facilitate the sub-sequential injection of the viral nucleic acid through the cell wall.
Suppose you are performing a nucleic acid hybridization assay to identify a newly isolated bacterium. If you lower the incubation temperature to roughly 25°C below the melting temperature (Tm) instead of keeping it strictly at 10°C to 15°C below the Tm, the hybridization process will become _______________ (more selective/less selective) regarding base pairing stringency.
Less selective
Distinguish between primary and secondary endosymbiosis in photosynthetic eukaryotes by specifying the key difference in evolutionary origin between the chloroplasts found in the Archaeplastida (red and green algae) versus those found in other chloroplast-bearing protists.
The chloroplasts of red and green algae (Archaeplastida) arose directly from a primary endosymbiotic event (engulfing a photosynthetic cyanobacterium). In contrast, other chloroplast-bearing protists acquired theirs via secondary endosymbiosis (engulfing a eukaryotic red or green alga that already contained a primary chloroplast).