Exam 24: Early Life and the Diversification of Prokaryotes

The termite gut protist Mixotricha paradoxa has at least two kinds of bacteria attached to its outer surface.One bacterium is a spirochete that propels its protist host through the termite gut.A second type of bacteria synthesizes ATP,some of which is used by the spirochetes.The locomotion provided by the spirochetes introduces the ATP-producing bacteria to new food sources.Which of the following terms is (are)applicable to the relationship between the two kinds of bacteria?

Bacteria can rarely colonize and contaminate foods with high sugar content,such as syrup,honey,jelly,or bags of sugar,even if these products are left open in warm temperatures.The reason they do not become contaminated is because bacteria that encounter these foods

Figure 24.2 depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell.Hfr cell DNA begins entering the recipient cell at time A.Assume that reciprocal crossing over occurs (in other words,a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA).Use Figure 24.2 to answer the following question(s). Figure 24.2 -During which two times can the recipient accurately be described as "recombinant" due to the sequence of events portrayed in Figure 24.2?

The prokaryotic CRISPR-Cas system

A fish that has been salt-cured subsequently develops a reddish color.You suspect that the fish has been contaminated by the extreme halophile Halobacterium.Which of these features of cells removed from the surface of the fish,if confirmed,would support your suspicion?

This bacterium derives nutrition by digesting human intestinal contents (in other words,food).Thus,this bacterium should be an

Chloramphenicol is an antibiotic that targets prokaryotic (70S)ribosomes but not eukaryotic (80S)ribosomes.Which of these questions stems from this observation plus an understanding of eukaryotic origins?

-The predatory bacterium Bdellovibrio bacteriovorus drills into a prey bacterium and,once inside,digests it.When the predatory bacterium attacks the gram-negative bacterium,what are the first structures penetrated by B.bacteriovorus on its way into the prey's cytoplasm?

Which photograph in the figure shows the cellular structure observed in species such as Staphylococcus epidermis,Staphylococcus aureus,and Streptococcus pneumoniae?

The first genetic material on early Earth was most likely

Which of these statements about prokaryotes is correct?

Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth.Which of these questions is currently the most challenging and would have the greatest impact on our understanding if we were able to answer it?

In 2009,which of the following did scientists discover was possible on early Earth?

On early Earth,what substance is hypothesized to have played a key role to facilitate the formation of polymers of amino acids,polymers of RNA,and vesicles?

Which of the following is likely the greatest impact that organisms have ever had on Earth?

This bacterium derives nutrition by digesting human intestinal contents (in other words,food).Humans lacking this bacterium have no measurable reproductive advantage or disadvantage relative to humans who harbor this bacterium.Consequently,the bacterium can be properly described as which of the following? 1)symbiont 2)endotoxin 3)mutualist 4)commensal

Which portion of a typical prokaryotic flagellum is embedded in the cell wall and plasma membrane?

E)coli cells typically make most of their ATP by metabolizing glucose.Under the conditions of this experiment,what should be true of E.coli's generation time (especially early in the course of the experiment,but less so later on)?

The table depicts characteristics of five prokaryotic species (A-E).Use the information in the table to answer the following question(s). Table 24.1 -Which species in Table 24.1 is probably an important contributor of organic compounds such as sugars,which are then passed up through aquatic food chains?