Ch 27 Flashcards


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1

1) The predatory bacterium Bdellovibrio bacteriophorus drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm?

A) phospholipid membrane, capsule, peptidoglycan, lipopolysaccharide membrane

B) lipopolysaccharide membrane, peptidoglycan, capsule, phospholipid membrane

C) lipopolysaccharide membrane, capsule, peptidoglycan, phospholipid membrane

D) capsule, lipopolysaccharide membrane, peptidoglycan, phospholipid membrane

D

2

2) Jams, jellies, preserves, honey, and other foods with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment ________.
A) undergo death as a result of water loss from the cell

B) are unable to metabolize the glucose or fructose, and thus starve to death

C) are obligate anaerobes
D) are unable to swim through these thick and viscous materials

A

3

3) Use the information in the following paragraph to answer the question.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.

This bacterium's ability to survive in a human who is taking penicillin pills may be due to the presence of ________.
A) gram-negative cell wall
B) peptidoglycan in the cell wall

C) lipopolysaccharides in the cytoplasm

D) long polypeptides in the cell wall

A

4

4) Use the information in the following paragraph to answer the question.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.

Adherence to the intestinal lining by this bacterium is due to its possession of ________.

A) fimbriae
B) pili
C) a capsule

D) a flagellum

A

5

5) Use the information in the following paragraph to answer the question.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.

Which of the following statements about the cell wall is most probable?
A) Its innermost layer is composed of a phospholipid bilayer.
B) After it has been subjected to Gram staining, the cell should remain purple.

C) It has an outer membrane of lipopolysaccharide.
D) It is mostly composed of a complex, cross-linked polysaccharide.

C

6

6) Use the information in the following paragraph to answer the question.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.

In which feature should one be able to locate a complete chromosome of this bacterium?

A) mitochondrion
B) nucleoid
C) nucleus

D) plasmid

B

7

10) Which of the following observations about flagella is accurate and is consistent with the scientific conclusion that the flagella from eukaryotes and bacteria evolved independently?

A) The flagella of both eukaryotes and bacteria are made of the same protein, but the configuration is different.

B) The mechanics of movement and protein structure are the same in these flagella, but there are significant genetic differences.
C) Although the mechanism of movement in both flagella is the same, the protein that accomplishes the movement is different.

D) The protein structure and the mechanism of movement in eukaryotes flagella are different from those of bacteria flagella.

D

8

11) Which of the following observations about flagella is accurate and is consistent with the scientific conclusion that the flagella from archaea and bacteria evolved independently?
A) The flagella of the two groups differ in size.
B) The protein structures in the flagella are different.

C) The mechanisms of rotation are similar.
D) Both groups have flagella like those found in eukaryotes.

B

9

12) In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures?
A) nucleoid, fimbriae, and plasmids

B) endospore, fimbriae, and plasmids

C) fimbriae, nucleoid, and endospore

D) plasmids, nucleoid, and endospore

D

10

13) If a bacterium regenerates from an endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably also lack ________.
A) antibiotic-resistant genes

B) a cell wall
C) a chromosome
D) water in its cytoplasm

A

11

14) Chloramphenicol is an antibiotic that targets prokaryotic (70S) ribosomes, but not eukaryotic (80S) ribosomes. Which of these questions stems from this observation, plus an understanding of eukaryotic origins?
A) Can chloramphenicol also be used to control human diseases that are caused by archaeans?

B) Can chloramphenicol pass through the capsules possessed by many cyanobacteria?

C) If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes?
D) Why aren't prokaryotic ribosomes identical to eukaryotic ribosomes?

C

12

15) Termites eat wood, but many do not produce enzymes themselves that will digest the cellulose in the wood. Instead, some termites house a complex community of protozoa, bacteria, and archaea that could help digest the cellulose. Imagine an experiment that fed termites either wood only or wood and antibiotics, and then measured the amount of energy extracted from the wood. If both groups gained equal amounts of energy, which of the conclusions is the most logical?
A) We would conclude that the protozoa contributed to digestion of cellulose and lignin.
B) We would conclude that the archaea contributed to digestion of cellulose and lignin.
C) We would conclude that the bacteria did not contribute to digestion of cellulose and lignin. D) We would conclude that none of the three groups were needed to digest cellulose and lignin.

C

13

22) A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. The cell also lacks F factors and F plasmids. Which of the following statements about the bacteria is most probably accurate?

A) The bacterium cannot donate DNA through conjugation with another cell.

B) The bacterium cannot take up DNA from its external environment.
C) The bacterium cannot form an endospore.
D) The bacterium cannot reproduce.

A

14

30) In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid, then the result should be the ________.
A) temporary possession by this bacterium of a completely diploid genome

B) rapid spread of tetracycline resistance to other bacteria in that habitat

C) subsequent loss of tetracycline resistance from this bacterium
D) production of endospores among the bacterium's progeny

B

15

31) Which of the following is least associated with the others?

A) horizontal gene transfer
B) conjugation
C) transformation

D) binary fission

D.

16

34) Use of synthetic fertilizers often leads to the contamination of groundwater with nitrates. Nitrate pollution is also a suspected cause of anoxic "dead zones" in the ocean. Which of the following might help reduce nitrate pollution?
A) growing improved crop plants that have nitrogen-fixing enzymes

B) adding nitrifying bacteria to the soil
C) adding denitrifying bacteria to the soil
D) using ammonia instead of nitrate as a fertilizer

A

17

35) Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in ________.
A) their sources of carbon
B) their electron acceptors

C) their mode of inheritance
D) the way that they generate ATP

A

18

37) A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. This bacterium derives nutrition by digesting human intestinal contents. Thus, this bacterium is an ________.

A) aerobic chemoheterotroph

B) aerobic chemoautotroph
C) anaerobic chemoheterotroph

D) anaerobic chemoautotroph

C

19

38) Use the following information to answer the question.

Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free oxygen (O2) reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein

photosynthesis produces free O2. Consider the colonial aquatic cyanobacterium, Anabaena,

whose heterocysts are described as having "...a thickened cell wall that restricts entry of O2

produced by neighboring cells. Intercellular connections allow heterocysts to transport fixed nitrogen to neighboring cells in exchange for carbohydrates."

Given that the enzymes that catalyze nitrogen fixation are inhibited by oxygen, what mechanism might nitrogen-fixing prokaryotes use to protect these enzymes from oxygen?
A) couple the nitrogen fixation enzymes with photosystem II (the photosystem that splits water)

B) package the nitrogen fixation enzymes in membranes that are impermeable to all gases

C) live only in anaerobic environments
D) package the nitrogen fixation enzymes in membranes that are impermeable to nitrogen gas (N2).

C

20

39) Use the following information to answer the question.

Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free oxygen (O2)

reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein photosynthesis produces free O2. Consider the colonial aquatic cyanobacterium, Anabaena, whose heterocysts are described as having "...a thickened cell wall that restricts entry of O2 produced by neighboring cells. Intercellular connections allow heterocysts to transport fixed nitrogen to neighboring cells in exchange for carbohydrates."

Think about this description of the colonial aquatic cyanobacterium, Anabaena. Which of the following questions below is important for understanding how nitrogen (N2) enters heterocysts,

and how oxygen (O2) is kept out of heterocysts?
A) If carbohydrates can enter the heterocysts from neighboring cells via the "intercellular connections," how is it that O2 doesn't also enter via this route?

B) If the cell walls of Anabaena photosynthetic cells are permeable to O2 and carbon dioxide (CO2), are they also permeable to N2?

C) If the nuclei of the photosynthetic cells contain the genes that code for nitrogen fixation, how can these cells fail to perform nitrogen fixation?
D) If the nuclei of the heterocysts contain the genes that code for photosynthesis, how can these cells fail to perform photosynthesis?

A

21

41) If plaque on teeth is actually a biofilm, which of the following characteristics would you expect to find in plaque?
A) multiple species of bacteria, production of chemicals that attract other bacteria, and production of chemicals that allow the bacteria to adhere to enamel

B) single species of bacteria, production of antibiotics, and mechanisms in the biofilm that allow inner cells to expel wastes
C) multiple species of bacteria, production of antibiotics, and mechanisms in the biofilm that allow inner cells to expel wastes

D) single species of bacteria, production of chemicals that attract other bacteria, and production of chemicals that allow the bacteria to adhere to enamel

A

22

42) Use the following information to answer the question.

For several decades now, amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin. They can also be lethargic, which is expressed through failure to hide and failure to flee. The infection cycle typically takes four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection.

If infection primarily involves the outermost layers of adult amphibian skin, and if the chytrids use the skin as their sole source of nutrition, then which term best applies to the chytrids?
A) anaerobic chemoautotroph
B) aerobic chemoautotroph

C) anaerobic chemoheterotroph
D) aerobic chemoheterotroph

D

23

43) While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya?
A) Cell walls are made primarily of peptidoglycan.

B) The organism does not have a nucleus.
C) The lipids in its plasma membrane consist of glycerol bonded to straight-chain fatty acids.

D) It can survive at a temperature over 100°C.

A

24

44) Which of the following describe all existing bacteria?

A) pathogenic, omnipresent, morphologically diverse
B) extremophiles, tiny, abundant
C) tiny, ubiquitous, metabolically diverse

D) morphologically diverse, metabolically diverse, extremophiles

C

25

45) You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium?
A) It is able to form colonies and produce oxygen.
B) It is an endosymbiont.

C) It forms chains called mycelia.
D) It lacks cell walls.

A

26

46) Which statement about the domain Archaea is accurate?
A) Genetic prospecting has recently revealed the existence of many previously unknown archaean species.
B) The genomes of archaeans are unique, containing no genes that originated within bacteria.

C) No archaeans can inhabit solutions that are nearly 30% salt.
D) No archaeans are adapted to waters with temperatures above the boiling point.

A

27

47) Which of the following traits do archaeans and bacteria share?

A) composition of the cell wall
B) composition of the cell wall and lack of a nuclear envelope
C) lack of a nuclear envelope and presence of circular chromosome

D) presence of plasma membrane and composition of the cell wall

C

28

48) Which of the following traits do archaeans and eukaryotes share?

A) presence of a nuclear envelope
B) presence of peptidoglycan in the cell wall
C) sensitivity to streptomycin

D) presence of introns

D

29

49) Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?
A) extreme halophiles
B) extreme thermophiles

C) methanogens
D) cyanobacteria

A

30

50) The thermoacidophile Sulfolobus acidocaldarius lacks peptidoglycan, but still possesses a cell wall. Which of the following statements is likely to be an accurate description of this species?
A) It is a bacterium.

B) The optimal pH of its enzymes will lie above pH 7.

C) It could inhabit hydrothermal springs.
D) It could inhabit alkaline hot springs.

C

31

51) A fish that has been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would support your suspicion?
A) the presence of the same photosynthetic pigments found in cyanobacteria and cell walls that lack peptidoglycan

B) cell walls that lack peptidoglycan and are isotonic to conditions on the surface of the fish

C) cells unable to survive salt concentrations lower than 9% and cells containing many ion pumps on the plasma membrane
D) the presence of the same photosynthetic pigments found in cyanobacteria and cells that are isotonic to conditions on the surface of the fish

B

32

53) Which of the following extremophiles might researchers most likely use as a model for the earliest organisms on Earth?
A) a bacterium found on another planet or moon
B) an archaean capable of surviving in the polar ice caps

C) an anaerobic archaean species
D) a bacterium that thrives in a highly acidic environment

A

33

54) Mitochondria are thought to be the descendants of certain alpha proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosomes have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

A) plasmolysis
B) conjugation
C) translation
D) horizontal gene transfer

D

34

55) Recently, a microbe that is able to digest cellulose was discovered in a hot spring with an average temperature of 95°C. Predict the group to which this microbe most likely belongs. A) Archaea
B) Proteobacteria

C) Cyanobacteria
D) Fungi

A

35

56) Bacteria perform each of the following ecological roles. Which role typically does not involve symbiosis?
A) skin commensalist
B) decomposer

C) aggregator with methane-consuming archaea D) gut mutualist

B

36

57) Use the following information to answer the question.

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae.

A P. bursaria cell that has lost its zoochlorellae is aposymbiotic. If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship?

A) parasitic
B) commensalistic
C) toxic
D) mutualistic

B

37

58) Use the following information to answer the question.

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae.

Which of the following experimental results would suggest that the zoochlorellae and P. bursaria are mutualists?
A) The reproductive rate of P. bursaria is higher with zoochlorellae than without.
B) The mortality rate of P. bursaria is higher with zoochlorellae than without.

C) Zoochlorellae reproduce more slowly than free-living Chlorella.
D) The swimming speed of P. bursaria is higher with zoochlorellae than without.

A

38

59) If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?
A) Human populations would thrive in the absence of disease.
B) Bacteriophage numbers would dramatically increase.

C) The recycling of nutrients would be greatly reduced, at least initially.

D) There would be no more pathogens on Earth.

C

39

61) What is the goal of bioremediation?
A) to improve human health with the help of living organisms such as bacteria

B) to clean up areas polluted with toxic compounds by using bacteria
C) to improve soil quality for plant growth by using bacteria
D) to improve bacteria for production of useful chemicals

B

40

62) Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth?
A) refrigeration: slows bacterial metabolism and growth
B) closing previously opened containers: prevents more bacteria from entering, and excludes oxygen

C) pickling: creates a pH at which most bacterial enzymes cannot function
D) canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells

B

41

63) Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently, assuming that nothing is done to counter the reduction of intestinal bacteria, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become ________.
A) unable to fix carbon dioxide

B) antibiotic resistant
C) unable to synthesize peptidoglycan
D) deficient in certain vitamins and nutrients

D

42

64) The pathogenic prokaryotes that cause cholera are ________.

A) archaea that release an exotoxin
B) archaea that release an endotoxin
C) bacteria that release an exotoxin

D) bacteria that release an endotoxin

C

43

65) Leaf-cutter ants harvest plant leaves and bring them back to their nests. There, in the warm, moist environments of their underground nests, they grow fungi (Leucoagaricus) that they then eat. These ants also host bacteria on their exoskeleton. Another fungus, Escovopsis, kills Leucoagaricus when the ants are removed from the nest. Knowing that the bacteria on the ants are in the same phylogenetic group of other bacteria that produce antibiotics, which of the following research hypotheses is most likely correct?

A) The bacteria on the exoskeleton produce chemicals that kill Leucoagaricus.

B) The bacteria on the exoskeleton produce chemicals that kill Escovopsis.
C) The bacteria on the exoskeleton provide nutrition to the ants.
D) The bacteria on the exoskeleton cause disease in the ants.

C

44

66) When a virus infects a bacterial cell, often new viruses are assembled and released when the host bacterial cell is lysed. If these new viruses go on to infect new bacterial cells, the new host cells may not be lysed. What is the most plausible explanation for this?
A) The bacterial cell must be resistant to infection by the virus.

B) The virus carries genes that confer resistance to the host bacterial cell.
C) The host bacterium couples the viral infection with transformation.
D) The virus has entered the genome of the bacterial cell and is in the lysogenic stage.

D

45

67) Sexual reproduction in eukaryotes increases genetic variation. In prokaryotes, transformation, transduction, and conjugation are mechanisms that increase genetic variation. A fundamental difference between the generation of genetic variation in the two domains is ________.
A) eukaryotes are able to generate mutations in response to environmental stress while prokaryotes only generate random variation
B) eukaryotic variation occurs primarily within a single generation while prokaryotic variation occurs over many generations
C) crossing over is a major mechanism in creating genetic variation in prokaryotes while independent assortment is a major mechanism in eukaryotes
D) eukaryotic genetic variation occurs when adults transmit genes to their offspring while prokaryotic genetic variation occurs with horizontal gene transfer

D

46

68) In prokaryotes, new mutations accumulate quickly in populations, while in eukaryotes, new mutations accumulate much more slowly. The primary reasons for this are ________.
A) prokaryotes have short generation times and large population sizes
B) prokaryotes have random mutations while eukaryotes can target genes for mutations; thus mutations may not accumulate as quickly in eukaryotes, but they are more useful to the organism

C) the DNA in prokaryotes is not as stable as eukaryotic DNA and is thus more likely to mutate

D) prokaryote mutations are less effective than eukaryote mutations in providing variation for evolution

A

47

69) Compared to eukaryotes, prokaryotes are ________.
A) less sensitive to the physical environment
B) simpler morphologically and more evolutionarily primitive
C) simpler morphologically, but not more evolutionarily primitive D) more complex morphologically and more primitive

C

48

Which of the following statements is not true?
A) Archaea and bacteria have different membrane lipids.
B) The cell walls of archaea lack peptidoglycan.
C) Only bacteria have histones associated with DNA.
D) Only some archaea use CO2 to oxidize H2, releasing methane.

C

49

Bacteria perform the following ecological roles. Which role typically does not involve symbiosis?
A) skin commensalist
B) decomposer

C) gut mutualist
D) pathogen

B

50

Plantlike photosynthesis that releases O2 occurs in

A) cyanobacteria.
B) gram-positive bacteria.
C) archaea.
D) chemoautotrophic bacteria.

A