11) Which of the following would support the statement that bacteria represent the most fundamentally diverse group on Earth?

A) Bacteria exist in varieties with and without cell walls.

B) Bacteria accomplish all characteristics of life as small, single cells.

C) Bacteria are metabolically diverse regarding oxygen and food requirements.

D) Bacteria come in several different shapes.

12) Which statement about the relationship between bacteria and the human body is most accurate?

A) Although many tissues are kept bacteria-free, around 100 trillion bacteria live on or in us.

B) About one-tenth of our body weights are due to bacteria

C) Bacteria are found in the mouth, stomach, and intestines in about equal amounts.

D) Most bacteria are transient; that is, they come for brief periods and then are gone.

13) Which of the following would support the hypothesis that bacteria have mutually beneficial relationships with us?

A) Bacteria derive benefit from waste materials in our intestines.

B) Mice that were made “germ free” did not absorb and metabolize nutrients as well.

C) Bacteria can metabolize food using alternate pathways.

D) Most intestinal bacteria cannot live outside the body.

14) Bacteria that benefit from living in or on us while we are unaffected by the relationship are termed:

A) commensal.

B) pathogenic.

C) mutualistic.

D) probiotic.

15) A bacterium that is pathogenic:

A) is flexible regarding use of metabolic pathways.

B) has genes similar to viruses.

C) is a disease-causing organism.

D) benefits from living inside humans and produces nutrients for us.

16) The botulism bacterium can kill a person by:

A) killing muscle cells.

B) secreting a toxin that paralyzes muscles.

C) causing brain hemorrhages.

D) producing lethally high fevers.

17) If antibiotics seem effective against a human illness, then this illness is probably caused by a/an:

A) protist.

B) autoimmune disease.

C) virus.

D) bacterium.

18) In general, most antibiotics work by:

A) exploiting differences between human and bacterial cells.

B) preventing bacteria from entering human cells.

C) preventing viruses from entering human cells.

D) boosting the human immune system.

19) The antibiotic penicillin inhibits the ability of bacteria to:

A) make cell walls.

B) synthesize protein.

C) copy DNA.

D) undergo respiration.

20) Which of the following is true of Domain Archaea compared to other groups?

A) They are the only anaerobes on Earth.

B) Their cell wall and membrane biochemistry is unique.

C) Most of their genes are similar to those found in bacteria.

D) None of their genes work like those found in eukaryotes.

Refer to the scenario below, and then answer the following question(s).

As part of your field biology independent study, you visit a small lake with an extremely high salt concentration. Searching with nets and other sampling devices, you find no fish, plants, algae, or any visible signs of life in the lake. Still, you decide to take a few samples of the water back to the lab. You find the sample teeming with very small cells, hundreds of times smaller than a typical human cell. These cells have cell walls, which you analyze chemically and find they are not made of peptidoglycan or cellulose.