Mycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which of the statements below is true about mycoplasmas?
b. They are subject to lysis in hypotonic conditions.
Though plants, fungi, and prokaryotes all have cell walls, we classify them under different taxonomic units. Which of the observations below comes closest to explaining the basis for placing these organisms in different taxa?
b. Their cell walls are constructed from very different biochemicals.
Which of the following have been present in Earth's living organisms for the least amount of evolutionary time?
Which of the following statements about bacterial cell walls is false?
c. Cell walls prevent cells from dying in hypertonic conditions.
Which of the following statements is correct about gram-negative bacteria?
b. They often possess an outer membrane containing toxic lipopolysaccharides.
Which of the following is the most common compound in the cell walls of gram-positive bacteria?
If penicillin is an antibiotic that inhibits enzymes from catalyzing the synthesis of peptidoglycan, then which prokaryotes should be most vulnerable to inhibition by penicillin?
b. gram-positive bacteria
Which of the following is the correct order, from most external to most internal?
e. 3, 1, 2
Jams, jellies, preserves, honey, and other foodstuffs with a high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment
a. undergo death by plasmolysis.
In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium performs conjugation involving a copy of this plasmid, then the result should be
b. the rapid spread of tetracycline resistance to other bacteria in that habitat.
In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures?
d. 1, 3, and 5
Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces?
b. 1 and 3
The typical prokaryotic flagellum features
c. a complex motor embedded in the cell wall and plasma membrane.
Prokaryotes have ribosomes different from those of eukaryotes. Because of this, which of the following is true?
a. Some selective antibiotics can block protein synthesis of bacteria without harming the eukaryotic host.
Which of the following is a correct statement about the genomes of prokaryotes?
d. Prokaryotic chromosomes are not contained within a nucleus but, rather, are found at the nucleoid region.
If a bacterium regenerates from an endospore that does not have all of the plasmids contained in its parent cell, it will probably
a. lack "contingency" functions.
In regard to prokaryotic reproduction, which of the following is true?
d. Mutation is a primary source of variation in prokaryote populations.
Which of the following statements about prokaryotes is correct?
c. They divide by binary fission, without mitosis or meiosis.
About half of all prokaryotes are capable of directional movement. The following statements are all true of such directional movement except that
a. it may occur via flagellar action.
composed almost entirely of peptidoglycan
D. cell wall