Chapter 27 Questions

Question 1

Prokaryotes lack some parts found in eukaryotic cells, including which item?

a. a nuclear membrane
b. DNA
c. one or more chromosomes
d. a plasma membrane
e. all of the above

Answer 1

a. a nuclear membrane

Question 2

Which of the following statements best describes most bacteria?

a. They are generally harmful.
b. They are limited to living in a few habitats.
c. They are very common in the environment.
d. They are responsible for the “common cold.”

Answer 2

c. They are very common in the environment.

Question 3

Which statement about biofilms would lose points on an exam?

a. Growth is due to signaling molecules recruiting cells.
b. Cells secrete sticky proteins and polysaccharides.
c. Damage to industrial equipment costs billions.
d. Nutrients and wastes travel through channels.
e. They are uncommon in nature.

Answer 3

e. They are uncommon in nature.

Question 4

In what type of environment would you find extreme halophiles?

a. ice
b. hot springs
c. vary salty water
d. anoxic swamps
e. a rain forest

Answer 4

c. vary salty water

Question 5

Which gets its energy from sunlight and its carbon from ingesting other organisms?

a. photoautotroph
b. chemoautotroph
c. photoheterotroph
d. chemoheterotroph

Answer 5

c. photoheterotroph

Question 6

If your veterinarian told you that your dog tested positive for Chlamydia, your dog is probably __.

a. pregnant
b. old
c. mate
d. sick
e. darkly pigmented

Answer 6

d. sick

Question 7

While preparing a lab, you remove a culture of prokaryotes from their incubator and place them, still alive, on the bench at 25 degrees C. All die within 2 hours. The culture probably contained which prokaryotes?

a. extreme halophiles
b. preoteobacteria
c. cyanobacteria
d. methanogens
e. extreme thermophiles

Answer 7

e. extreme thermophiles

Question 8

A research ships catches a fish from the depths of the ocean. In the dark, it glows. What are prokaryotes doing with the fish?

a. decomposing it
b. providing bioluminescence
c. fixing nitrogen
d. photosynthesizing

Answer 8

b. providing bioluminescence

Question 9

You take a culture from our mouth and grow it in an incubator. You observe that the cells that grow have introns and branched hdyrocarbons in their plasma membranes. What best explains this?

a. There are archaea in your mouth.
b. You have very unusual membrane lipids due to a mutation.
c. The observations are erroneous.
d. None is correct.

Answer 9

a. There are archaea in your mouth.

Question 10

Without prokaryotes,

a. much decomposition in soil would stop.
b. PCR would be much more difficult to do.
c. plants would have fewer soil nutrients to absorb.
d. there would be less methane in the world.
e. all of the above would occur.

Answer 10

e. all of the above would occur.

Question 11

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. capsule, lipopolysaccharide, membrane, peptidoglycan, phospholipid membrane
b. phospholipid membrane, capsule, peptidoglycan, lipopolysaccharide membrane
c. lipopolysaccharide membrane, capsule, peptidoglycan, phospholipid membrane
d. lipopolysaccharide membrane, peptidoglycan, capsule, phospholipid membrane

Answer 11

a. capsule, lipopolysaccharide, membrane, peptidoglycan, phospholipid membrane

Question 12

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following question.
Table.
Which species is capable of directed movement?
a. species A
b. species B
c. species C
d. species D

Answer 12

c. species C

Question 13

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. Although the mechanism of movement in both flagella is the same, the protein that accomplishes the movement is different.
b. The flagella of both eukaryotes and bacteria are made of the same protein, but the configuration is different.
c. The mechanics of movement and protein structure are the same in these flagella, but there are significant genetic differences.
d. The protein structure and the mechanism of movement in eukaryotes flagella are different from those of bacteria flagella.

Answer 13

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

Question 14

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. endospore, fimbriae, and plasmids
b. nucleoid, fimbriae, and plasmids
c. fimbriae, nucleoid, and endospore
d. plasmids, nucleoid, and endospore

Answer 14

d. plasmids, nucleoid, and endospore

Question 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 none of the three groups were needed to digest cellulose and lignin.
c. We would conclude that the bacteria did not contribute to digestion of cellulose and lignin.
d. We would conclude that the archaea contributed to digestion of cellulose and lignin.

Answer 15

c. We would conclude that the bacteria did not contribute to digestion of cellulose and lignin.

Question 16

The figure below depicts changes to the amount of DNA present in a recipient cell that is engaed in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient’s chromosome is exchanged for a homologous fragment from the Hfr cell’s DNA).
Figure.
How is the recipient cell different at Time D than it was at Time A?
a. It has a greater mass of DNA.
b. It contains bacteriophage DNA.
c. It has a greater number of genes.
d. It has a different sequence of base pairs.

Answer 16

d. It has a different sequence of base pairs.

Question 17

In this eight-year experiment, 12 populations of E.coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.
Graph.
If the experimental population of E.coli lacks an F factor or F plasmid, and if bacteriophages are excluded from the bacterial cultures, then beneficial mutations might be transmitted horizontally to other E.coli cells via ___.
a. conjugation
b. transformation
c. transduction
d. sex pili

Answer 17

b. transformation

Question 18

Which of the following is least associated with the others?

a. transformation
b. binary fission
c. horizontal gene transfer
d. conjugation

Answer 18

b. binary fission

Question 19

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. adding denitrifying bacteria to the soil
b. adding nitrifying bacteria to the soil
c. using ammonia instead of nitrate as a fertilizer
d. growing improved crop plants that have nitrogen-fixing enzymes

Answer 19

d. growing improved crop plants that have nitrogen-fixing enzymes

Question 20

Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in ___.

a. their sources of carbon
b. their mode of inheritance
c. the way that they generate ATP
d. their electron acceptors

Answer 20

a. their sources of carbon

Question 21

If plaque on teeth is actually a biofilm, which of the following characteristics would you expect to find in plaque?

a. single species of bacteria, production of chemicals that attract other bacteria, and production of chemicals that allow the bacteria to adhere to enamel
b. multiple species of bacteria, production of antibiotics, and mechanisms in the biofilm that allow inner cells to expel wastes
c. single species of bacteria, production of antibiotics, and mechanisms int he biofilm that allow inner cells to expel wastes
d. multiple species of bacteria, production of chemicals that attract other bacteria, and production of chemicals that allow the bacteria to adhere to enamel

Answer 21

d. multiple species of bacteria, production of chemicals that attract other bacteria, and production of chemicals that allow the bacteria to adhere to enamel

Question 22

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. It can survive at a temperature over 100 degrees C.
b. Cell walls are made primarily of peptidoglycan.
c. The lipids in its plasma membrane consist of glycerol bonding to straight-chain fatty acids.
d. The organism does not have a nucleus.

Answer 22

b. Cell walls are made primarily of peptidoglycan.

Question 23

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. It can survive at a temperature over 100 degrees C.
b. Cell walls are made primarily of peptidoglycan.
c. The lipids in its plasma membrane consist of glycerol bonded to straight-chain fatty acids.
d. The organism does not have a nucleus.

Answer 23

b. Cell walls are made primarily of peptidoglycan.

Question 24

Which of the following describe all existing bacteria?

a. pathogenic, omnipresent, morphologically diverse
b. morphologically diverse, metabolically diverse, extremophiles
c. extremophiles, tiny, abundant
d. tiny, ubiquitous, metabolically diverse

Answer 24

d. tiny, ubiquitous, metabolically diverse

Question 25

You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium?

a. It is an endosymbiont.
b. It forms chains called mycelia.
c. It is able to form colonies and produce oxygen.
d. It lacks cell walls.

Answer 25

c. It is able to form colonies and produce oxygen.

Question 26

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 thermophiles
b. extreme halophiles
c. cyanobacteria
d. methanogens

Answer 26

b. extreme halophiles

Question 27

Recently, a microbe that is able to digest cellulose was discovered in a hot spring with an average temperature of 95 degrees C. Predict the group to which this microbe most likely belongs.

a. Proteobacteria
b. Fungi
c. Archaea
d. Cyanobacteria

Answer 27

c. Archaea

Question 28

If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?

a. There would be no more pathogens on Earth.
b. Bacteriophage numbers would dramatically increase.
c. The recycling of nutrients would be greatly reduced, at least initially.
d. Human populations would thrive in the absence of disease.

Answer 28

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

Question 29

In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf’s nonliving, waxy covering while inhibiting the growth of other microbes that are plant pathogens. If this bacterium gains access to the inside of a leaf, however, it causes a fatal disease in the plant. Once the plant dies, the bacterium and its offspring decompose the plant. What is the correct sequence of ecological roles played by the bacterium in the situation described here?

a. mutualist, pathogen, nutrient recycler
b. nutrient recycler, commensal, pathogen
c. mutualist, commensal, pathogen
d. nutrient recycler, mutualist, primary producer

Answer 29

a. mutualist, pathogen, nutrient recycler

Question 30

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. deficient in certain vitamins and nutrients
b. unable to synthesize peptidoglycan
c. unable to fix carbon dioxide
d. antibiotic resistance

Answer 30

a. deficient in certain vitamins and nutrients

Question 31

In prokaryotes, new mutations accumulate quickly in populations, while in eukaryotes, new mutations accumulate much more slowly. The primary reasons for this are ___.

a. the DNA in prokaryotes is not as stable as eukaryotic DNA and is thus more likely to mutate
b. prokaryotes have short generation times and large population sizes
c. prokaryote mutations are less effective than eukaryote mutations in providing variation for evolution
d. 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

Answer 31

b. prokaryotes have short generation times and large population sizes

Question 32

Genetic variation in bacterial populations cannot result from

a. transduction.
b. conjugation.
c. mutation.
d. meiosis.

Answer 32

d. meiosis.

Question 33

Photoautotrophs use

a. light as an energy source and CO2 as a carbon source
b. light as an energy source and methane as a carbon source
c. N2 as an energy source and CO2 as a carbon source
d. CO2 as both an energy source and a carbon source

Answer 33

a. light as an energy source and CO2 as a carbon source

Question 34

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.

Answer 34

c. Only bacteria have histones associated with DNA.

Question 35

Which of the following involves metabolic cooperation among prokaryotic cells?

a. binary fission
b. endospore formation
c. biofilms
d. photoautotrophy

Answer 35

c. biofilms

Question 36

Bacteria perform the following ecological roles. Which role typically does not involve symbiosis?

a. skin commensalist
b. decomposer
c. gut mutualist
d. pathogen

Answer 36

b. decomposer

Question 37

Plantlike photosynthesis that releases O2 occurs in

a. cyanobacteria
b. archaea
c. gram-positive bacteria
d. chemoautotrophic bacteria

Answer 37

a. cyanobacteria