Exam 26: Bacteria and Archaea

You may know that scientists are able to synthesize new strands of DNA through a process known as PCR, which utilizes a DNA polymerase derived from bacteria. By repeatedly heating the reaction products to 70°C, researchers can create new DNA from a template DNA strand. What does this tell you about bacteria compared to archaeons?

Which of the following statements is TRUE regarding Staphylococcus bacteria?

Recall that the Archaea are commonly characterized as having three main groups. Which of the following is NOT one of the major archaeon groups?

During _____ photosynthesis, H₂S, H₂, Fe²⁺, or AsO₃^3- can be oxidized.

Two graduate students are trying to identify new species of bacteria based on the criteria of Ernst Mayr. They are having a lot of trouble with this method, and then suddenly realize that they can't use Mayr's definition of a species for identifying bacteria species. Why not?

Recall that Firmicutes tend to be found in the intestinal tracts of individuals with certain diets. Based on this distribution, Firmicutes likely play a role in which of the following processes?

Which of the following statements is TRUE regarding bacteria?

In the early stages of Earth's history, iron, rather than oxygen, was a key player in the carbon cycle.

During oxygenic photosynthesis, water is _____ and loses electrons. (i.e., it serves as an electron donor).

Archaeons are never found in the human gut-the stomach and intestines are only populated by bacteria.

If O₂ and N₂ are present in equal amounts in an environment, both will have an equal chance of serving as an electron acceptor during respiration (i.e., organisms do not have a preference as to which molecule is reduced).

Which of the following statements is TRUE regarding archaeons?

Whereas the gene encoding the small subunit of ribosomes was used to generate the tree of life, many genes are inappropriate choices for this type of analysis because these genes have been subject to horizontal gene transfer for billions of years.

Oxygen is used during a reaction if the process is:

Bacteria or archaeons can be which of the following types of organisms?

A marine biologist descends in a submarine through the waters of the Black Sea. The top hundred meters or so are well oxygenated, but deeper waters are rich in hydrogen sulfide. What biological metabolisms can explain the distribution of H₂S in the Black Sea?

A student is carrying out a science experiment. She takes battery acid and introduces several different types of microorganisms into it. Which of the following organisms would MOST likely survive?

Imagine that aliens are attempting to grow humans in sterile chambers. Much to the aliens' disappointment, these humans are sickly, despite the fact that they have no bacteria in their gastrointestinal tracts. What could these experiments tell you about how bacteria populate the human gut?

If all eukaryotes suddenly died off, the Earth's carbon cycle would immediately collapse and cease to exist.

Comparisons of rRNA gene sequences to determine evolutionary relationships among cultured bacteria (e.g., those that can be grown in pure culture in the laboratory) supported all the traditional grouping that bacterial taxonomists created based on morphology, physiology, and other metabolic characteristics.