Exam 25: Bacteria, Archaea, and Viruses

A patient is admitted to the hospital complaining of itchy eyes.After a few diagnostic tests, the doctors determine that the symptoms are being caused by small Gram-negative cocci that appear to have two types of cell morphology.With this information they conclude that the infection is likely caused by

If a phylogenetic tree were constructed using sequences from eukaryotic mitochondrial DNA and bacterial and archaeal genomes, it would suggest a close relationship between _______ and eukaryotes (or mitochondria).

Eukarya is evolutionarily closer to _______ than it is to Bacteria.

Which of the following interfere(s) with the synthesis of peptidoglycan-containing cell walls?

Which statement about archaea is true?

When a key nutrient such as nitrogen or carbon becomes scarce, some bacteria replicate their DNA and encapsulate one copy, along with some cytoplasm, in a tough cell wall heavily thickened with peptidoglycan and surrounded by a spore coat.The parent cell then breaks down.The result is

Photoautotrophs use light as their source of energy and _______ as their source of carbon.

In light, purple sulfur bacteria use H₂S as an electron donor and release pure sulfur as a waste product.Purple sulfur bacteria are thus

The genetic makeup of many viruses supports the hypothesis that they are derived from "escaped" cellular components.In contrast, which class of viruses best supports the hypothesis that certain viruses have evolved from highly reduced parasitic organisms?

Which statement about archaea is false?

Which statement concerning the human microbiome is false?

An electron transport system is an important feature of cellular respiratory pathways.In these pathways, humans and other aerobes obtain an electron acceptor from the atmosphere or an aqueous environment, but anaerobic prokaryotes use oxidized inorganic ions as electron acceptors.Which of the following is not an electron acceptor used by either aerobes or anaerobes?

Refer to the figure, which shows the formation of a biofilm. According to the figure, which statement about biofilms is true?

Refer to the figure, which shows a prokaryote. Which statement about the structures labeled "internal flagella" (which compose the axial filament) is true?

Cyanobacteria

Which of the following statements concerning axial filaments is false?

Your research group is studying a bacterium known to produce a medically relevant biofilm.In an effort to understand how the biofilm is induced, you mutate one of the bacterium's genes (gene X) that you believe to be involved in quorum sensing.Design an experiment to determine whether gene X is involved in biofilm formation.Be sure to include the reasoning behind your experimental design in your answer.

Because of complications during delivery of identical twins, "Baby A" is born vaginally while "Baby B" is born by cesarean section.As the twins have aged, Baby B alone has begun to experience rheumatoid arthritis (RA).Which explanation most likely accounts for the autoimmune disease endured by Baby B?

Which statement about the proteobacteria is false?

Escherichia coli and Salmonella typhimurium are both members of the