Deck 16: Microbial Life: Prokaryotes and Protists

Question 1

Prokaryotic cell walls function

A) to promote flexibility and formation of pseudopodia.
B) to prevent the cell from bursting in a hypotonic environment.
C) to propel cells (locomotion).
D) as a site of metabolic reactions (photosynthesis and cellular respiration).

Answer 1

B

Question 2

Rod-shaped bacteria are called

A) cocci.
B) bacilli.
C) spirochetes.

Answer 2

B

Question 3

Which statement about archaea is false?

A) Archaea cannot survive in very hot temperatures.
B) Archaea are abundant in the oceans.
C) Some archaea live in the digestive tracts of cattle.

Answer 3

A

Question 4

One difference between gram-positive and gram-negative bacteria is that

A) gram-positive bacteria have more peptidoglycan in their cell walls.
B) gram-positive bacteria have fimbriae but gram-negative bacteria do not.
C) gram-positive bacteria are spiral-shaped, and gram-negative bacteria are either rod-shaped or spherical.
D) only gram-negative bacteria can form endospores.

Question 5

Eukaryotes are ________ prokaryotes.

A) more ancient than
B) dependent upon
C) more widespread than
D) more numerous than

Question 6

Evidence for similarities between Archaea and Eukarya includes the

A) absence of introns from genes in both groups.
B) fact that both contain circular DNA without histones.
C) presence of peptidoglycan in the cell walls of both groups.
D) fact that both have several kinds of relatively complex RNA polymerases.

Question 7

The largest group of prokaryotes is the ________, which obtain both energy and carbon from ________.

A) autotrophs; inorganic molecules
B) chemoautotrophs; decaying organic material
C) chemoheterotrophs; organic molecules
D) photoautotrophs; light

Question 8

Which is a member of the domain Archaea?

A) gram-positive bacteria
B) methanogens
C) spirochetes
D) chlamydias

Question 9

A bacterium living in an underground septic tank thrives by absorbing organic compounds from decomposing wastes. What is it?

A) a chemoautotroph
B) a chemoheterotroph
C) a photoautotroph
D) a photoheterotroph

Question 10

Unlike archaean and eukaryote cell walls, bacterial cell walls contain a unique substance called

A) cellulose.
B) peptidoglycan.
C) phospholipid.
D) glycogen.

Question 11

The trickling filter at a sewage treatment plant works by

A) passing wastewater through fine sand and then mechanically removing fine pollution particles.
B) passing wastewater through a thick bed of rocks that contains chemicals that sterilize the water and neutralize chemical pollutants.
C) passing wastewater through a thick bed of rocks where biofilms of bacteria and fungi on the rocks remove much of the organic material dissolved in the wastewater.
D) adding fertilizer to wastewater and then passing it through a culture medium that is rich in oil-eating prokaryotes.

Question 12

Chemoautotrophic bacteria obtain their carbon from ________ and their energy from ________.

A) CO2; sunlight
B) CO2; inorganic chemicals
C) methane; sunlight
D) organic molecules; sunlight

Question 13

An unknown bacterial species is recovered from a sick patient's digestive tract. It has a membrane outside the cell wall that contains toxic lipids. This observation indicates that

A) the infection should be relatively easy to control with common antibiotics, because the pathogen is a gram-positive species.
B) the infection should be relatively easy to control with common antibiotics, because the pathogen is a gram-negative species.
C) the infection may be quite threatening and difficult to control, because the pathogen is a gram-positive species.
D) the infection may be quite threatening and difficult to control, because the pathogen is a gram-negative species.

Question 14

Which of the following options correctly pairs a structure in prokaryote cells with its function?

A) fimbriae, help prokaryotes stick to each other and to surfaces
B) capsule, rigid protective structure enclosing cell
C) flagella, feeding appendages
D) endospore, food digestion vacuole

Question 15

A layer of organized colonies of bacteria coating a surface is also known as a

A) halophile.
B) tissue.
C) biofilm.
D) plague.

Question 16

Intestinal gas is evidence of active ________ in some animals' digestive tracts.

A) thermophiles
B) methanogens
C) yeast cultures
D) halophiles

Question 17

Individual prokaryote cells are ________ eukaryote cells; collectively, all prokaryote cells on Earth ________.

A) the same size as; weigh about one-tenth the total mass of eukaryote cells
B) much larger than; weigh about 10 times as much as the total mass of eukaryote cells
C) much smaller than; weigh about one-tenth the total mass of eukaryote cells
D) the same size as; weigh about 10 times as much as the total mass of eukaryote cells

Question 18

A scientist cultures the dried soup from a 4,000-year-old cooking pot found in an Egyptian tomb and obtains a distinctive species of prokaryote. She immerses a test tube of these bacteria in boiling water for several hours, but the colony grows back. This species is probably

A) halophilic.
B) endospore-forming.
C) a spirochete.
D) a cyanobacteria.

Question 19

The use of prokaryotes and other organisms to clean up pollutants from soil, air, or water is called

A) decomposition.
B) nitrogen fixation.
C) bioremediation.
D) metagenomics.

Question 20

Prokaryotes are classified into

A) domain Protista and domain Archaea.
B) kingdom Bacteria and kingdom Archaea.
C) domain Bacteria and domain Archaea.
D) kingdom Protista and kingdom Bacteria.

Question 21

Which of the following cellular structures is characteristic of amoebas?

A) pseudopodia
B) microvilli
C) cilia
D) flagella

Question 22

Protists include

A) a single clade of eukaryotes that are distantly related to animals.
B) two clades of eukaryotes: one is related to animals and fungi, and the other is related to plants.
C) two clades of eukaryotes: algae and protozoans.
D) multiple clades of eukaryotes.

Question 23

The main ingredient of crude oil is

A) diatoms.
B) dinoflagellates.
C) bacteria.
D) algae.

Question 24

________ are toxic proteins secreted by pathogenic bacteria, and ________ are toxic components of the outer membrane of gram-negative bacteria.

A) Endotoxins; parasites
B) Endotoxins; botulinum toxins
C) Exotoxins; enterotoxins
D) Exotoxins; endotoxins

Question 25

Which of the following groups includes protists that reside within the cells of corals?

A) brown algae
B) diatoms
C) dinoflagellates
D) ciliates

Question 26

Diatoms

A) are autotrophs with a glassy cell wall that contains silica.
B) are mixotrophs.
C) are heterotrophic protists that decompose dead plants and animals in freshwater habitats.
D) include the malaria parasite.

Question 27

________ are heterotrophic protists; ________ are photoautotrophic protists.

A) Mixotrophs; protozoans
B) Protozoans; algae
C) Protozoans; plants
D) Parasites; protozoans

Question 28

Cyanobacteria

A) are photosynthetic archaea.
B) are eukaryotes and the earliest type of algae.
C) are chemoautotrophs.
D) are the only prokaryotes with plantlike, oxygen-generating photosynthesis.

Question 29

Which two groups of protists produce hard, mineralized skeletal structures or cell walls that contribute to marine sediments and form fossils?

A) green algae and brown algae
B) foraminiferans and radiolarians
C) dinoflagellates and diatoms
D) cellular slime molds and water molds

Question 30

Which of the following causes food poisoning?

A) Escherichia coli
B) Bacillus anthracis
C) Vibrio cholerae
D) Thiomargarita namibiensis

Question 31

Plasmodium, the organism that causes malaria, is a(n)

A) amoeba.
B) stramenopile.
C) ciliate.
D) alveolate.

Question 32

Two diseases that represent high-priority threats as biological weapons today are

A) smallpox and typhus.
B) syphilis and HIV.
C) anthrax and botulinum.
D) anthrax and Salmonella.

Question 33

Which of the following groups include organisms that are a key source of food in all aquatic environments and whose fossilized forms are used as a filter and as a grinding and polishing agent?

A) diatoms
B) brown algae
C) amoebas
D) dinoflagellates

Question 34

Barry Marshall and his collaborators showed that

A) lifestyle factors such as stress, diet, and smoking cause chronic gastritis and stomach ulcers.
B) lab animals are easily infected by Helicobacter pylori.
C) Helicobacter pylori bacteria are protective against peptic ulcers.
D) Helicobacter pylori bacteria cause chronic gastritis and stomach ulcers.

Question 35

Which of the following is a parasitic excavate that causes African sleeping sickness, a disease spread by the tsetse fly?

A) Plasmodium
B) Trypanosoma
C) Paramecium
D) Amoeba

Question 36

Kelp, a seaweed that is anchored to the seafloor by rootlike structures and can grow to heights of 60 m, is a kind of

A) water mold.
B) brown alga.
C) green alga.
D) diatoms.

Question 37

Dinoflagellates are best described as

A) protozoans that use cilia to move and feed.
B) a clade of protists including unicellular autotrophs, heterotrophs, and mixotrophs
C) parasitic diatoms that must spend part of their life cycles in vertebrate hosts.
D) large, multicellular algae that resemble plants but do not have true leaves, stems, or roots.

Question 38

________ are stramenopiles that commonly are found decomposing dead animals in freshwater habitats.

A) Brown algae
B) Water molds
C) Cellular slime molds
D) Plasmodial slime molds

Question 39

The term for a close association between organisms of two or more species is

A) symbiosis.
B) exotoxin.
C) endotoxin.
D) mixotrophic.

Question 40

Which organisms are common soil decomposers that grow in colonies of branched chains of cells that superficially resemble a fungus?

A) actinomycetes
B) cyanobacteria
C) proteobacteria
D) cocci

Question 41

There is a good chance you will eat carrageenan today and that you will eat nori at some point in your life, if you haven't already. In either case, you will be eating a product of

A) brown algae.
B) red algae.
C) green algae.
D) diatoms.

Question 42

What mode of nutrition would you predict that a prokaryote would use if it is placed in an aquatic environment that has moderate sunlight availability as well as dead plant material?

A) photoautotrophic behavior
B) chemotrophic behavior
C) mixotrophic behavior
D) chemoautotrophic behavior

Question 43

A patient visits her doctor complaining of stomach cramps, vomiting, and nausea. When he takes a bacterial sample, he determines that Escherichia coli bacteria have used their ________ to attach to the cells lining her gastrointestinal tract.

A) cilia
B) flagella
C) fimbriae
D) peptidoglycan

Question 44

When hermit crabs crawl across the ocean floor, they often have sea anemones attached to their backs. The anemones use their dangerous tentacles to keep hermit crab predators at bay, and they dine on the particles of food that the crab does not eat. This is an example of

A) bioremediation.
B) alternation of generations.
C) symbiosis.
D) endosymbiosis.

Question 45

You hang a microscope slide from a submerged, L-shaped PVC pipe in lake water that is 2 feet deep. The slide hangs 6 inches below the surface of the water and remains there for eight weeks. When you remove it and bring it to your lab for observation, you see that algae, bacteria, and even some fungi have colonized the slide. You determine that you are looking at a(n)

A) biofilm.
B) community of eukaryotes.
C) biological weapon.
D) endotoxin.

Question 46

You take a 1-mL sample of pond water and add it to a colorless, viscous media in a small petri dish. When you place it under your dissecting microscope, you see three organisms. Two are struggling to move efficiently through the media, while the third moves more quickly. You attribute the faster movement to the third organism's

A) thick cell wall.
B) flagella.
C) fimbriae.
D) chloroplasts.

Question 47

Humans are an example of

A) chemoautotrophs.
B) photoautotrophs.
C) chemoheterotrophs.
D) photoheterotrophs.

Question 48

The famous pink-colored sand of Bermuda's beaches is due to crushed shells of ________, marine organisms with tests (porous shells) made of organic material hardened by calcium carbonate.

A) radiolarians
B) green algae
C) foraminifera
D) lobsters

Question 49

In a process called phytoremediation, specific plants are planted in areas where toxic chemicals have contaminated groundwater. The roots absorb the contaminants to help eliminate the tainted water, which is often drinking water. This is an example of

A) bacteria culturing.
B) algae harvesting.
C) bioremediation.
D) genetic engineering.

Question 50

In what way does the green alga Ulva resemble land plants?

A) It produces diploid gametes.
B) It has a complex life cycle with diploid body cells and haploid gametes.
C) It has a complex life cycle with alternation between multicellular diploid and haploid generations.
D) It has a multicellular haploid stage that alternates with a unicellular diploid stage.

Question 51

A scientist collects a protist from a rotting log. He grows the protist in a petri dish that contains Escherichia coli bacteria; the protist engulfs the bacteria. For a while the protist multiplies as single cells. When the E. coli are all consumed, the protists aggregate to form a clump that rises up to become a stalked structure with a globular head. What kind of protist does the scientist have?

A) a plasmodial slime mold
B) a cellular slime mold
C) a free-living amoeba
D) a water mold

Question 52

The bacteria Pseudomonas aeruginosa produces a protein that is secreted into its environment. The protein inhibits synthesis of elongation factor 2 (another protein) in humans. This effect may sound dangerous, but it has been considered as a possible treatment for hepatitis B. The protein produced by P. aeruginosa is a(n)

A) endotoxin.
B) exotoxin.
C) biological weapon.
D) biofilm.

Question 53

You are studying a mini-ecosystem that you created from samples of lake water, plants, and sediment. Your teacher tells you to drop about 10 sesame seeds on the top of the water because they will attract some interesting organisms. One week later, you see that the seeds are surrounded by white fuzz that is extending off of the seeds, and you conclude that the decomposing seeds have been colonized by

A) diatoms.
B) brown algae.
C) unikonts.
D) water molds.

Question 54

Multicellular organisms evolved from three different ancestral lineages: stramenopiles, unikonts, and archaeplastids. Of these, fungi and animals evolved from two different lineages of ________, and land plants are ________.

A) alveolates; unikonts
B) alveolates; archaeplastids
C) unikonts; archaeplastids
D) archaeplastids; unikonts

Question 55

Many species of which protist group have modified mitochondria that lack functional electron transport chains?

A) excavates
B) rhizarians
C) ciliates
D) unikonts

Question 56

Plasmodial slime molds

A) are photoautotrophic.
B) are marine decomposers.
C) contain many nuclei in one mass of cytoplasm.
D) are primitive fungi.

Question 57

In 2012, scientists discovered that colonies of single-celled organisms can be found in high numbers in the human gut. Scientists are particularly concerned with the colonies that produce methane, as methane in the human gut can be linked to constipation and irritable bowel syndrome (IBS). The scientists can classify these colonies as belonging to the domain

A) Archaea.
B) Bacteria.
C) Eukarya.
D) Protista.

Question 58

In 2012, scientists studied modern Marchantia liverwort plants and observed that they not only are able to make their own food using energy from sunlight but they also absorb carbon from plant material in aquatic environments. They classified this plant as a

A) chemoheterotroph.
B) photoautotroph.
C) mixotroph.
D) chemoautotroph.

Question 59

Bioventing is a scientific technology that uses microorganisms to break down components of fuels in groundwater. Bioventing is an example of

A) genetic engineering.
B) bioremediation.
C) algae harvesting.
D) bacteria culturing.

Question 60

When snapping shrimp are building their homes in the seafloor, goby fish keep guard and flap their tails when danger is approaching. As part of this relationship, the shrimp allow the gobies to sleep in the burrow and use it for cover from predators. This is an example of

A) symbiosis.
B) biofilms.
C) bioremediation.
D) endosymbiosis.

Question 61

After reading the paragraphs below, answer the questions that follow.
In the 1930s, the Navajo Nation treated sheep and cattle for ticks and other parasites by using concrete "dip tanks," a common practice in the United States during that time period. Animals were herded into one end of the tank and out the other. Each day, the tanks were filled with 200,000 gallons of insecticide, and any remaining chemicals were emptied onto the ground. The pesticide solution seeped into the ground, ditches, and pits around the tanks.
In the 1990s, the EPA Emergency Response Team (ERT) was called to the Navajo Nation to investigate the problem. They concluded that bioremediation procedures were the best option for cleaning up the site. Certain types of bacteria are able to feed on and digest toxic organic substances, such as pesticides, and use them as fuel for cell respiration. The ERT distributed these pesticide-eating microorganisms throughout the contaminated soil to remove the chemical residues. Once the contaminants are degraded, these microorganism populations will die off because they will have used up all of their food supply.
What evolutionary adaptations might the pesticide-eating bacteria have that allow them to be useful in this context? They likely

A) fed on pesticides present on the early planet Earth.
B) fed on the tissues and blood of cattle and sheep.
C) fed on biofilms that colonize anaerobic environments.
D) fed on molecules with a chemical structure similar to pesticides.

Question 62

Traditional microbial genomics and cultivation methods have given scientists access to approximately 1% of microbial genetic diversity. This is because most microbes cannot be grown up, or cultured, on petri dishes. Which scientific field would allow scientists to have a much greater access to an environment's genetic resources?

A) agriculture
B) forestry
C) bioremediation
D) metagenomics

Question 63

After reading the paragraphs below, answer the questions that follow.
Textile mills often release dye color and toxic by-products into rivers and streams, which may then taint groundwater. Fungi associated with mangrove trees have been shown to reduce both colors and toxicity in tainted groundwater.
The fungi are being used as a form of

A) endosymbiosis.
B) bioremediation.
C) phagocytosis.
D) mixotrophy.

Question 64

The following figure from your text shows a simplified eukaryote phylogeny. From this figure, answer the following questions.
Which of the following contains only protist clades?

A) SAR
B) Excavata
C) Unikonta
D) Archaeplastida

Question 65

Alginates are used in many everyday products, including toothpaste and soap. When added to water, they form a thick gel that binds or emulsifies liquids. Alginates come from a group of multicellular stramenopiles that have one pigment that masks all others and therefore gives these organisms a distinctive, dark color. Alginates are derived from

A) green algae.
B) brown algae.
C) water molds.
D) dinoflagellates.

Question 66

A negative impact of biofilms in the human body is that biofilms can cause head and neck diseases. A study was completed that compared three groups of medical patients for presence or absence of biofilms. Group 1 were patients with chronic otitis media (COM), a disease where the eardrum continually drains and can often become clogged, that also displayed ear discharge. Group 2 were COM patients without ear discharge. Group 3 were patients undergoing surgery for cochlear implantation, a procedure where a small electronic instrument is placed in the ear to carry out normal functions of the inner ear. Two microscopy methods were used to detect presence of biofilms in all patients of both groups: direct microscopy (DM) and transmission electron microscopy (TEM).
The table below shows the results of presence or absence of biofilms in all study participants.
Table 1. Number of study participants detected with biofilms
$$\begin{array} { | l | l | l | l | } \hline \text { Group } & \text { Group Size } & \text { Biofilm on DM } & \text { Biofilm on TEM } \\\hline 1 \text { COM, discharge } & 10 & 10 & 10 \\ \hline 2\text { COM no discharge } & 9 & 2 & 2 \\ \hline3 \text { B cochlear implant } & 10 & 0 & 0 \\\hline \text { Total } & 29 & 12 & 12 \\\hline\end{array}$$ Source: Adapted from Aky?ld?z, I., Take, G., Uygur, K., K?z?l, Y., & Aydil, U. (2013). Bacterial biofilm formation in the middle-ear mucosa of chronic otitis media patients. Indian J Otolaryngol Head Neck Surg, 557-561. doi:10.1007/s12070-012-0513-x

-Which group served as the control group in the experiment?

A) 1
B) 2
C) 3

Question 67

Some current research efforts are investigating whether or not ________, a group of prokaryotes with the ability to produce oxygen as a by-product of photosynthesis, can be used as a source of renewable energy by converting sunlight into electricity.

A) chlamydias
B) spirochetes
C) proteobacteria
D) cyanobacteria

Question 68

A negative impact of biofilms in the human body is that biofilms can cause head and neck diseases. A study was completed that compared three groups of medical patients for presence or absence of biofilms. Group 1 were patients with chronic otitis media (COM), a disease where the eardrum continually drains and can often become clogged, that also displayed ear discharge. Group 2 were COM patients without ear discharge. Group 3 were patients undergoing surgery for cochlear implantation, a procedure where a small electronic instrument is placed in the ear to carry out normal functions of the inner ear. Two microscopy methods were used to detect presence of biofilms in all patients of both groups: direct microscopy (DM) and transmission electron microscopy (TEM).
The table below shows the results of presence or absence of biofilms in all study participants.
Table 1. Number of study participants detected with biofilms
$$\begin{array} { | l | l | l | l | } \hline \text { Group } & \text { Group Size } & \text { Biofilm on DM } & \text { Biofilm on TEM } \\\hline 1 \text { COM, discharge } & 10 & 10 & 10 \\ \hline 2\text { COM no discharge } & 9 & 2 & 2 \\ \hline3 \text { B cochlear implant } & 10 & 0 & 0 \\\hline \text { Total } & 29 & 12 & 12 \\\hline\end{array}$$ Source: Adapted from Aky?ld?z, I., Take, G., Uygur, K., K?z?l, Y., & Aydil, U. (2013). Bacterial biofilm formation in the middle-ear mucosa of chronic otitis media patients. Indian J Otolaryngol Head Neck Surg, 557-561. doi:10.1007/s12070-012-0513-x

-How can you interpret results of the study?

A) All patients with a history of ear discharge and two without ear discharge were found by DM and TEM to have presence of biofilms.
B) All cochlear transplant patients were found by DM to have presence of biofilms.
C) Half of the patients with ear discharge were found to be free of biofilms.
D) Cochlear transplant patients were found to have more occurrences of biofilms than all other study patients.

Question 69

Some white blood cells are able to surround and ingest bacteria. Which of the following would you expect to see as part of the blood cell structure?

A) secondary cell walls
B) flagella
C) pseudopodia
D) cilia

Question 70

If you place an organism classified as a photoautotroph at the bottom of a lake and later see that it is able to acquire nutrients from dead plant material, you can conclude the photoautotroph is actually a

A) photoheterotroph.
B) chemoautotroph.
C) chemoheterotroph.
D) mixotroph.

Question 71

Dunaliella salina is a bacterium that is able to live in aqueous solutions with such high salt concentrations that the salt cannot fully dissolve. D. salina is an example of a(n)

A) extreme thermophile.
B) extreme halophile.
C) methanogen.
D) proteobacteria.

Question 72

The following figure from your text shows a simplified eukaryote phylogeny. From this figure, answer the following questions.
Which stage of the life cycle of Ulva shown is the sporophyte?

A) stage A
B) stage B
C) stage C
D) stage D

Question 73

A negative impact of biofilms in the human body is that biofilms can cause head and neck diseases. A study was completed that compared three groups of medical patients for presence or absence of biofilms. Group 1 were patients with chronic otitis media (COM), a disease where the eardrum continually drains and can often become clogged, that also displayed ear discharge. Group 2 were COM patients without ear discharge. Group 3 were patients undergoing surgery for cochlear implantation, a procedure where a small electronic instrument is placed in the ear to carry out normal functions of the inner ear. Two microscopy methods were used to detect presence of biofilms in all patients of both groups: direct microscopy (DM) and transmission electron microscopy (TEM).
The table below shows the results of presence or absence of biofilms in all study participants.
Table 1. Number of study participants detected with biofilms
$$\begin{array} { | l | l | l | l | } \hline \text { Group } & \text { Group Size } & \text { Biofilm on DM } & \text { Biofilm on TEM } \\\hline 1 \text { COM, discharge } & 10 & 10 & 10 \\ \hline 2\text { COM no discharge } & 9 & 2 & 2 \\ \hline3 \text { B cochlear implant } & 10 & 0 & 0 \\\hline \text { Total } & 29 & 12 & 12 \\\hline\end{array}$$ Source: Adapted from Aky?ld?z, I., Take, G., Uygur, K., K?z?l, Y., & Aydil, U. (2013). Bacterial biofilm formation in the middle-ear mucosa of chronic otitis media patients. Indian J Otolaryngol Head Neck Surg, 557-561. doi:10.1007/s12070-012-0513-x

-What can you conclude from the study?

A) If ear discharge is treated with a lose-dose antibiotic, COM will not be established in a patient.
B) Treatment for patients with COM may be challenging due to the presence of biofilms.
C) Cochlear ear transplant patients should be concerned about contracting COM.
D) Biofilms are naturally present in the human ear.

Question 74

Which of the following statements regarding Ulva is true?

A) Ulva, a brown algae, resembles land plants because it produces diploid gametes.
B) Ulva, a brown algae, has a complex life cycle with diploid body cells and haploid gametes.
C) Ulva, a green algae, has a complex life cycle with diploid body cells and haploid gametes.
D) Ulva, a green algae, has a complex life cycle with alternation between multicellular diploid and haploid generations.

Question 75

After reading the paragraphs below, answer the questions that follow.
Textile mills often release dye color and toxic by-products into rivers and streams, which may then taint groundwater. Fungi associated with mangrove trees have been shown to reduce both colors and toxicity in tainted groundwater.
Suppose that fungal treatment was added to stream water contaminated from a textile mill. The toxins in the water tend to lower pH levels, and scientists wanted to study how adding the fungal treatment affected stream pH levels. pH levels were recorded every year for five years. Results indicated that the acidity of the stream water decreased from pH 2.5 in the first year to pH 5.9 by the fifth year. Scientists concluded that

A) the fungal treatment had little to no effect on detoxifying the stream water.
B) the fungal treatment had a positive effect on detoxifying the stream water.
C) the fungal treatment had completely detoxified the stream water.
D) there was not enough evidence to determine the effects of the fungal treatment on the toxic stream water.

Question 76

Compost piles create an intense heat source and would therefore be suitable environments for

A) extreme thermophiles.
B) extreme halophiles.
C) methanogens.
D) proteobacteria.

Question 77

Someone diagnosed with meningitis has inflamed membranes that cover and protect the brain and spinal cord. Meningitis is a result of pathogenic gram-negative bacteria that cause extreme infections when their bacterial cell wall dies and lipopolysaccharide (a lipid and polysaccharide) is released. The lipopolysaccharide is an example of a(n)

A) endotoxin.
B) exotoxin.
C) stomach microbiota.
D) parasite.

Question 78

The following figure from your text shows a simplified eukaryote phylogeny. From this figure, answer the following questions.
How do you characterize SAR, Excavata, Unikonta, and Archaeplastida?

A) They are all protist clades.
B) They are all nonprotist clades.
C) They are all eukaryote supergroups.
D) They are all diatoms.

Question 79

The following figure from your text shows a simplified eukaryote phylogeny. From this figure, answer the following questions.
Which group has the least scientific support for its position in the phylogeny?

A) SAR, because the phylogeny indicates that stramenopiles, alveolates, and rhizarians have only partial scientific support of evolutionary relationships.
B) Excavata, because the phylogeny indicates this group is not related to any other group in the phylogeny.
C) Unikonta, because the phylogeny indicates that fungi and animals are only partially evolutionarily related to one another.
D) Archaeplastida because the phylogeny indicates that red and green algae have stronger relationships with one another than with land plants.

Question 80

After reading the paragraphs below, answer the questions that follow.
In the 1930s, the Navajo Nation treated sheep and cattle for ticks and other parasites by using concrete "dip tanks," a common practice in the United States during that time period. Animals were herded into one end of the tank and out the other. Each day, the tanks were filled with 200,000 gallons of insecticide, and any remaining chemicals were emptied onto the ground. The pesticide solution seeped into the ground, ditches, and pits around the tanks.
In the 1990s, the EPA Emergency Response Team (ERT) was called to the Navajo Nation to investigate the problem. They concluded that bioremediation procedures were the best option for cleaning up the site. Certain types of bacteria are able to feed on and digest toxic organic substances, such as pesticides, and use them as fuel for cell respiration. The ERT distributed these pesticide-eating microorganisms throughout the contaminated soil to remove the chemical residues. Once the contaminants are degraded, these microorganism populations will die off because they will have used up all of their food supply.
The bacteria used in this bioremediation procedure are

A) chemoautotrophs.
B) photoautotrophs.
C) chemoheterotrophs.
D) photoheterotrophs.