26. Prokaryotes

Bacteria perform the following ecological roles. Which role typically does not involve symbiosis?a. skin commensalistb. decomposerc. gut mutualistd. pathogen

Which statement is true regarding cholera?

Organisms that use light for their energy source and CO₂ for their carbon source are called __________.

In an experiment, a microbiologist put equal numbers of each of the following organisms into a flask of sterile broth, consisting mostly of sugar and a few amino acids. She then placed the flask in the dark. Which of the organisms would be most likely to survive?

The Desulfovibrio bacterium breaks down organic matter (which it must have) and uses sulfate (not oxygen) as an electron acceptor. As a result, it produces hydrogen sulfide (H₂S), accounting for the "rotten egg" smell of swamp muck. Oxygen is a deadly poison to Desulfovibrio. We would call Desulfovibrio a(n) __________.

Choose the list below that contains the substances required by typical nitrogen-fixing cyanobacteria.

What is the role of heterocysts in a cyanobacterial filament?

Biofilms are an example of __________.

Which statement about prokaryotes is true?

Prokaryotes are completely indispensable to which chemical cycle?

A type of ecological relationship called __________ involves one organism living at the expense of another organism.

Which of the following statements about cyanobacteria is/are true?

Ticks that live on deer and field mice are responsible for spreading the bacterium __________, which causes __________.

Which example below is a correct statement about Bacteroides thetaiotaomicron, a bacterium that lives in the human intestines?

What do some photosynthetic bacteria use as a source of electrons instead of water?a. oxygen (O2)b. hydrogen sulfide (H2S)c. organic compounds (e.g., CH3COO−)d. nitrate (NO3-)