WorksheetsChapter 17
Total questions: 72
Worksheet time: 36mins
When explaining the concept of the human microbiome, the best explanation is that it is
a. a specific microorganism found within or on the human body.
b. all of the microorganisms that are found within the human digestive system.
c. the most predominant species of microorganism in the human body.
d. a community of microorganisms in a particular location on the human body.
e. the microorganisms that are capable of causing an infection in the human body.
Microbial forensics is the field of science that
is investigating all of the different ways in which microorganisms can cause death.
studies the different microbes that are detrimental to human survival.
is investigating the ways in which microbes can rapidly adapt to avoid death.
studies microbial composition of organisms after death.
studies the vast array of microorganisms that populate the Earth.
The body system that appears to contain the greatest diversity of microbial organisms is the
skin.
gastrointestinal tract.
respiratory system.
urogenital tract.
skeletal system.
Sampling a wide variety of surfaces that humans touch is a fairly easy, noninvasive way to provide scientists insight into
fingerprint patterns of different individuals.
the different types of microbes in the human gastrointestinal system.
how frequently individuals wash their hands.
the daily habits of individuals in their homes and businesses.
the variety of microbes that live on the surface of the skin.
Why can swabbing items such as keyboards, computer mice, pens, and phones provide an accurate representation of microbes living in association with humans?
The items such as keyboards, pens, phones, and others provide a great growth resource for microbes.
Microbes that naturally live on these surfaces survive better due to oils released from human skin.
You are presented with an image of a human hand and arm with different regions of the limb showing different colors. It is explained that this image was generated through microbial mapping and the different colors represent different
degrees of skin thickness in the different regions, illustrating the protective function of skin.
substances that the person came in contact with during the course of the day.
regions of the skin through which heat is more or less easily lost to maintain appropriate body temperature.
RNA activity in different cells of the limb.
molecules from different substances the person has ingested.
It can be difficult to know if a microbial swab has picked up a representative sample of microorganisms because
microorganisms are very sticky and are not swabbed from surfaces very easily.
swabbing techniques are fairly complicated and thus a lot of mistakes can be made.
prokaryotes are very small, between 1 and 10 micrometers in size, and thus cannot be seen without a microscope.
microorganisms dry out very quickly before swabs can be effectively analyzed.
prokaryotes are very large, on the order of 1–10 centimeters, so not many can be collected on a single swab.
The best description of a prokaryote is that it is
typically a unicellular organism between 1 and 10 micrometers in size.
most commonly a eukaryotic organism between 1 and10 micrometers in size.
generally found living and reproducing in isolation in inhospitable environments.
a set of unicellular organisms found living and growing in a common environment.
a unicellular organism between 1 and 2 millimeters in size.
Why would a researcher be slow, careful, and meticulous while swabbing for microbial samples on different surfaces in a home or office?
to sample as thoroughly and accurately as possible
to take as much time as possible to do the job well
so that the different microbes are not mixed up between the surfaces
because it is done remotely and requires skill
to isolate individual colonies of microbes as best as possible
Prokaryotes are highly successful biological organisms found throughout the world. Their success may be largely attributed to which characteristic?
They have a unique process for converting DNA into RNA.
They have cell walls for protection instead of only cell membranes.
Mutations do not occur in microbes; thus, they can replicate very quickly.
They are highly adaptable to a wide variety of environments.
They have a very rapid process for converting DNA into proteins.
What is a key phenotypic feature of prokaryotic organisms that allows them to survive in many different types of environments?
Their DNA can form small rings called plasmids, making it easier to replicate.
Nutritional and metabolic differences allow them to survive on a wide range of food sources.
They have a very rapid rate of DNA to RNA transcription and translation.
Their small size allows them to aggregate together to form larger biological structures.
Due to an extensive blood vessel network, they can thermoregulate very well in any environment.
Which statement correctly compares prokaryotic and eukaryotic cells?
Prokaryotic and eukaryotic cells are roughly the same size and shape.
DNA of prokaryotic cells is not contained in a nucleus whereas eukaryotic DNA is contained in a nucleus.
Prokaryotic cells are about one hundred times larger in size compared to eukaryotic cells.
Eukaryotes lack internal organelles, ribosomes, and DNA, all of which are found in prokaryotes.
Only prokaryotic cells have ribosomes, whereas eukaryotic cells have mitochondria that serve the same function.
How did the scientists ultimately identify the different species of prokaryotes they found in ancient human remains?
growth in lab cultures
comparison of DNA sequences
comparison of growth habitats
comparison of pH of the environment
location of the human remains
In aiming to learn about ancient microbes from human remains, what was the significant challenge Dr. Metcalf faced?
After death, microbes from the environment begin to decay the body, destroying the microorganisms found on and in the body.
Death of the human causes the microorganisms living on/in the body to also die and break down, leaving no trace of their existence.
After death, the microorganisms found on and in the body cause the body to decay until only the skeleton remains, destroying themselves in the process.
After death, fossilization may occur rapidly under the right circumstances, destroying the microorganisms found on and in the body.
Death of the human causes the microorganisms to leave the body to look for a new source of food and nutrition.
Current microbial forensics techniques have allowed scientists to be able to pinpoint the time of death within a fairly accurate range. How accurate is this time of death range?
within about 48 days of death
within about 15 days of death
within about 3 hours of death
within about 24 hours of death
within about 3 days of death
If a forensic report came back indicating that the greatest proportion of microbes found on the body were species of proteobacteria and basidiomycota, it would be reasonable to conclude that the person
was close to death.
died many years ago, leaving only dry remains.
died only a few minutes before the samples were collected.
If a forensic report came back indicating that the greatest proportion of microbes found on the body were species of proteobacteria, stramenopiles, zygomycota, and firmicutes, it would be reasonable to conclude that the person
died quite a while ago, resulting in a current state of advanced decay.
had recovered from a very serious infection.
was close to death.
died only a few minutes before the samples were collected.
died recently, resulting in bloating.
If a forensic report came back indicating that the greatest proportion of microbes found on the tissues were species of firmicutes and ascomycota, the remains would be most accurately described as
fresh remains, with blood pooling in the extremities and extremely rigid muscles.
actively decaying remains, accompanied by strong odors and release of fluids.
dry remains, mainly bone and cartilage.
bloated remains, with anaerobic bacteria producing a lot of gases.
loss of remains, no tissues are found, only a high concentration of these microbes in the soil.
A student researcher in a microbiology lab is assigned to swab various surfaces in an office to better understand the different microorganisms present in that location. To get the most accurate representation of microorganisms, the best approach would be to swab
every surface in the office even if it will take an extremely long time to complete.
all surfaces that are touched by two or more people, but none touched by only one person.
the places that are most frequently touched, whether by one person or multiple people.
all surfaces that are touched by only one person, but none touched by two or more people.
the places that are least frequently touched.
Sampling a wide variety of surfaces that humans touch is a fairly easy, noninvasive way for scientists to gather microbial data. What would be the best strategy to acquire the most representative samples?
Sample only items that can be documented as used by only one person.
Focus on sampling the most commonly touched items.
Focus on sampling items that were touched more than 24 hours earlier.
Sample only items that can be documented as used by two or more people.
Focus on sampling the least commonly touched items.
Before the invention of PCR (polymerase chain reaction) technology, how was biologist Dr. Carl Woese able to distinguish between different microbe species?
He used microscopy to look for specific differences under the microscope.
He identified a specific segment of ribosomal RNA, the 16S region, that is unique between organisms.
Although PCR had not been invented, the genetic code was known, so he tested DNA.
He identified types of messenger RNA (mRN that were unique to each species.
He distinguished different species based on the effect they had on organisms.
In classifying relationships among bacteria, how did Dr. Carl Woese associate species that are more closely related compared to those that are less closely related?
He used PCR technology to map how many similar rRNA sequences existed among the different microbe species, with more similarities indicating closer relationship.
He evaluated a specific segment of 16S rRNA and found that those species that had a smaller number of similar 16S rRNA regions were more closely related.
He used PCR technology to map how many similar DNA sequences existed among the different microbe species, with more similarities indicating closer relationship.
He evaluated the DNA of all the microbes to determine where mutations had occurred in each species, with species having fewer mutations being more closely related.
He evaluated a specific segment of 16S rRNA and found that those species who had a greater number of similar 16S rRNA sequences were more closely related.
A distinguishing feature of methanogens is that they
use carbon dioxide as their source for aerobic metabolism.
use methane as the gas to drive ATP production.
release oxygen as a by-product of producing ATP.
are unable to produce ATP.
die in the presence of oxygen.
During his analysis of various bacterial species, why did methanogens initially pose a challenge to Dr. Carl Woese’s bacterial classification strategy?
The 16S rRNA sequence of methanogens was not at all similar to any other bacteria he had classified.
The methanogens did not have any RNA, only DNA, thus Dr. Woese could not classify them.
The mRNA sequence Dr. Woese was analyzing in all bacteria was not present at all in the methanogens.
The DNA sequence of methanogens was so different from other bacteria that Dr. Woese ultimately classified them in a completely different domain.
The 5S tRNA sequence of methanogens did not function similarly to that of other bacteria he studied.
Why did Carl Woese propose the domain Archaea?
The domain Bacteria already had too many organisms in its classification.
The methanogens were discovered to be a complex organism, between prokaryotic bacteria and eukaryotes, thus it needed its own domain.
He discovered that methanogens were too large to be classified as bacteria, but too small to be classified as Eukarya.
In analyzing the rRNA of methanogens, he discovered that it was completely distinct from any other bacterial rRNA that had been studied.
The DNA of methanogens was discovered to use different nucleotides than those of organisms in Eukarya or Bacteria.
Which two domains contain prokaryotic organisms?
Archaea and Eukarya
Monera and Eukarya
Bacteria and Archaea
Archaea and Monera
Bacteria and Monera
Based on the information in Infographic 7.4, it can be concluded that humans are most genetically similar to which prokaryotes?
spirochetes
gram-positive bacteria
You cut yourself, and the cut becomes infected. The cause of this infection is most likely a _______ cell, which is a member of domain _______.
eukaryotic; Bacteria
eukaryotic; Archaea
prokaryotic; Bacteria
prokaryotic; Archaea
prokaryotic; Eukarya
Which method is the most reliable way to identify a new species of prokaryote?
differences in membrane structure and composition
differences in cell surface proteins and carbohydrates
differences in DNA sequences
differences in ribosomal RNA
differences in proteins
Which statement about the three domains of life is TRUE?
Archaea is most closely related to Bacteria.
Archaea is most closely related to Eukarya.
Bacteria is most closely related to Eukarya.
Bacteria and Archaea are equally related to the Eukarya.
Bacteria and Archaea have no evolutionary relationship to Eukarya.
This structure differs in its composition in Archaea and Bacteria.
cytoplasm
cell wall
nucleus
Golgi
nucleic acid
Which prokaryotes inhabit our intestines?
a. aerobic bacteria
b. halophiles
c. photosynthetic bacteria
d. anaerobic bacteria
e. thermophiles
Which is an adaptation for the survival of Helicobacter pylori in the stomach?
cilium
capsule
flagellum
pili
ribosomes
Which is an adaptation for the survival of Streptococcus mutans, which causes plaque buildup on teeth?
cilium
flagellum
pili
capsule
ribosomes
Which statement correctly pairs specific bacteria or groups of bacteria with their adaptations to specific habitats or lifestyles?
Symbiotic bacteria use their flagella to adhere to cells and tissues in intestinal tracts.
Photosynthetic bacteria use fermentation; we take advantage of this process to produce yogurt.
Bacteria living in the digestive tract of termites digest the cellulose of plant-cell walls, enabling the termite to feed on wood. The bacteria rely on the termite for food, and without these bacteria, the termites would starve. This relationship is an example of
symbiosis.
biosis.
parasitism.
anabolism.
fraternization.
In observing certain regions of the sea at sunset or after dark, it is often common to notice colorful, glowing organisms in the water. Although there are multiple reasons why this may occur, in certain species of squid it occurs because of
E. coli
S. aureus
L. bulgaricus
V. fischeri
S. mutans
After a large oil spill, scientists decide to utilize a technique called bioremediation to help clean up the spill. Bioremediation involves using ________ bacteria.
heterotrophic
aerobic
cyano
anaerobic
autotrophic
Which prokaryotes would be expected to have the best opportunity for survival in low-oxygen environments like wetlands?
E. coli
methanogens
photosynthetic bacteria
aerobes
halophiles
E. coli is a bacterium that is naturally found in the human digestive system and helps maintain the health of the digestive system. However, different strains of E. coli can cause significant digestive problems or illness. These illness-causing strains are collectively called
microbes.
symbiotic bacteria.
invasive bacteria.
pathogens.
halophiles.
In testing for microorganism survival in a salt mine, which prokaryotes would be expected to be surviving?
E. coli
methanogens
halophiles
photosynthetic bacteria
aerobes
The term “extremophiles” refers to
members of domain Bacteria
members of domain Archaea
members of domain Eukarya
members of both domains Bacteria and Archaea
members of both domains Archaea and Eukarya
The term “halophile” means “salt-loving” and describes organisms that live in extremely salty environments. Knowing this, you would expect a halophile to be a member of domain
Bacteria.
Archaea.
Eukarya.
Bacteria or Eukarya equally.
Archaea or Eukarya equally.
Which member of the domain Archaea would likely be found in the Great Salt Lake of Utah?
Halobacterium
Pyrodicticum
Thermoproteus
Methanosarcinia
Sulpholobus
Which member of the domain Archaea would likely be found in hot springs of volcanic origin?
Halobacterium
Sulpholobus
Pyrodicticum
In Yellowstone National Park’s Grand Prismatic Hot Spring, numerous colors are seen ringing the hot spring. What is the best explanation for the presence of these different colors?
There are different pigments in the soil that reflect light differently, producing the colors.
As the hot spring water cools down toward the edges of the spring, it causes the light to reflect off the water differently.
The rocks surrounding the hot spring leech different chemicals that become colored when exposed to sunlight.
As organisms around the hot spring die and decay, the different colors reflect the microbes present at each stage of decay.
Different microbe species produce different pigments that reflect light, producing the various colors.
One concern about modern farming is the high concentration of methane produced by cows. What causes cows to produce such high amounts of methane?
They have high concentrations of halophile microbes to manage a high salt diet.
They have high concentrations of sulpholobus microbes to survive low pH environments.
They have high concentrations of methanogen microbes to digest a cellulose-rich diet.
They have high concentrations of hyperthermophilic microbes to live in high temperature environments.
They have high concentrations of hypothermophilic microbes to live in very cold temperature environments.
At least some Archaea are called “extremophiles” because
as a group, they are extremely diverse.
as a group, they occupy an extremely large number of environments.
where they occur, they occur in extremely large numbers.
they can live in environments where abiotic conditions are extreme—extremely hot, salty, or toxic, for example.
they are extremely successful at reproducing.
Which statement about the domain Archaea is TRUE?
Their genetic material is RNA.
Their genetic material is housed in a nucleus.
Many archaea can survive in the absence of oxygen.
They have cell walls made of peptidoglycan.
They are only found in extreme environments.
Prokaryotic organisms that produce methane as a waste product are most likely to be members of domain __________.
Bacteria
Archaea
Eukarya
Bacteria or Archaea equally
Archaea or Eukarya equally
A scientist who wants to understand organisms that can live in extreme environments would most likely want to study members of domain
Bacteria.
Archaea.
Eukarya.
Bacteria or Eukarya equally.
Archaea or Eukarya equally.
If microbes are collected from an anaerobic environment then they must be processed in an anaerobic bag because
they are potentially harmful, and the anaerobic glove bag keeps scientists from being exposed to them.
the glove bag keeps samples of individual species from contaminating one another, which would make the microbes impossible to culture.
the anaerobic glove bag maintains a sterile environment that prevents any harmful microbes from growing.
the microbes are anaerobic and might be damaged if exposed to oxygen; the anaerobic glove bag eliminates oxygen.
the anaerobic glove bag supplies a high concentration of CO2, thus promoting survival of the samples.
Current scientific information indicates that the earliest way humans acquire the microbiome is by
passing through the mother’s birth canal.
including supplemental probiotics in baby formula.
breastfeeding.
supplementing baby foods at approximately 6 months of age.
consuming prebiotics and probiotics once an infant can eat solid foods.
The age at which most children will have a full complement of human microbiota is
at puberty, or approximately 12 years old.
at about 5 years old.
around 1-2 years old.
within 6 months of birth.
by about 10 years old.
A pregnant woman gets a bacterial infection at 8 months of pregnancy. After consulting with her physician, they agree that it would be beneficial for her to take a full course of antibiotics. What effect might this have on the infant at birth?
There will not be any effect on the infant at birth because it is the mother taking the antibiotics.
There will be a greater number of beneficial microbes, thus the infant will receive more microbiota than actually needed.
The antibiotics will destroy the pathogenic bacteria, but leave the beneficial bacteria intact, thereby protecting the infant.
The infant may be slightly lower weight than expected, because the mother would not be able to digest food as well due to the antibiotics.
The microbiota in the vaginal canal may be fewer in number and variety, thus the infant will not receive all of the expected microbiota.
After being diagnosed with a bacterial infection, an oral (taken by mouth) antibiotic was prescribed. After taking the full course of the antibiotic, what would be an expected outcome of the gut microbiome?
The gut microbiome would be completely eliminated due to the antibiotics.
There would not be a change in the gut microbiota if the antibiotic was prescribed for an infection elsewhere in the body.
More of the beneficial gut microbes would be present because eliminating the harmful microbes provided more room for the beneficial ones to grow.
Prior to the industrial revolution of the 18th–19th centuries, were human gut microbiomes more or less diverse, and why?
Less diverse because people ate a less diverse diet.
More diverse because people were susceptible to a lot more bacterial infections.
Less diverse because people consumed more medicines at that time in history.
More diverse because people ate a more diverse diet.
Less diverse because people did not have easy access to a wide variety of foods as we do now.
Which bacteria is less prevalent in modern diets than it was in traditional diets?
Leptospira
E. coli
Lactobacillus
Staphylococcus
Treponema
Good hygiene and improved farming practices have resulted in fewer bacterial pathogens in our food and bodies which has led to
fewer antibiotics being prescribed.
fewer infectious diseases.
a better understanding of which foods are the most healthful.
more infectious diseases.
more nutrient availability in the foods that are consumed.
Does the correlation between a less diverse gut microbiota and higher risks of diseases related to the immune system prove that Western diets are bad diets?
Yes, it does prove that relationship.
No, but it does prove that gut microbiota are required for healthy digestion.
Possibly, but more data need to be collected to truly prove this.
No, but it does prove more traditional diets were healthier for everyone.
No, it does not prove that relationship.
The ability of microbes to rapidly develop antibiotic resistance appears to be due, in part, to the fact that
wild populations of bacteria from indigenous peoples are able to mutate much faster than bacteria from people whose descendants were part of the industrial revolution.
bacteria that have never been exposed to antibiotics are able to replicate much faster than those that have been exposed to antibiotics.
wild populations of bacteria from indigenous peoples already contain genes for antibiotic resistance.
bacteria can learn from each other by trading genetic information and thus the wild populations gain this advantage from bacteria that were previously exposed.
wild populations of bacteria from indigenous peoples are much more diverse than antibiotic resistance.
The type of diet that promotes beneficial gut microbes is a
fiber-rich diet.
nut-rich diet.
fiber-poor diet.
probiotic-rich diet.
no-fiber diet.
The difference between prebiotics and probiotics is that prebiotics are
living bacteria intended to be consumed and introduced into the microbiome.
dormant beneficial bacteria that become active due to the low pH of the stomach.
foods grown in soils that have a large diversity of soil microbes.
components of food that promote the growth of beneficial microbes.
foods that are not processed at all, only consumed in their original form.
What is the advantage of receiving a fecal transplant?
It is the least invasive way to try and treat C. difficile infection.
There are no other medical options for treating a C. difficile infection.
It is the only treatment that has worked consistently to treat C. difficile infection.
The microbes found in feces of a healthy person are much different than those found in a sick person.
C. difficile will not be affected by a fecal transplant, but all other pathogenic bacteria will be eliminated.
After receiving a heavy dose of antibiotics while in the hospital, a patient experienced continuous bouts of diarrhea and colon inflammation. After completing a bit of research about the issue, the patient discovered that their symptoms were most likely due to
receiving too much fluid via intravenous (I) administration, upsetting the digestive system.
the fact that the antibiotics killed off many pathogenic and beneficial bacteria, allowing C. difficile to proliferate.
the fact that they did not receive enough prebiotics and probiotics while they were taking the antibiotics.
the hospital did not recognize the patient’s peanut allergy and provided food containing peanuts.
the fact that the antibiotics killed off all beneficial bacteria but all pathogenic bacteria remained and proliferated.
After receiving a heavy dose of antibiotics while in the hospital, a patient experienced significant bouts of diarrhea and colon inflammation. After completing a bit of research about the issue, the patient discovered that the most successful treatment strategy is
a. a different course of stronger antibiotics, which should be about 50% effective.
b. doubling the amount of prebiotics and probiotics they are currently taking.
c. eliminating sugar from the diet, which is most likely the main cause of the symptoms.
d. a fecal transplant, which is 80%-90% effective.
e. eating a diet of only fruits and vegetables, which is about 70% effective.
When scientists completed a fecal transplant from an obese mouse to a normal weight mouse, what results did they observe and what do these results indicate? The normal weight mice
lost weight, indicating that gut microbiome may play a role in weight management.
started consuming twice the amount of food, but did not gain weight, indicating that the gut microbiome increased metabolic rate.
did not exhibit any weight change, indicating that the gut microbiome does not play a role in weight management.
gained some weight, but did not become obese, indicating that the gut microbiome may slow metabolic rate.
became obese, indicating that the gut microbiome may play a role in weight management.
An 8 year old has a history of being a very picky eater, only eating foods such as breads, pastas, rice, and cheese. For other reasons, the child is ultimately diagnosed as autistic. Why might the child’s diet be evaluated as one option to manage the autism?
The diet is heavy on carbohydrate foods, possibly eliminating the child’s gut microbiome.
There are no fruits or vegetables being consumed, thus limiting essential nutrients needed by the body.
There are no plant-based sources of protein; therefore, some amino acids are missing from the diet.
The diet is heavy on processed foods, possibly decreasing the diversity of the child’s gut microbiome.
The diet has no nuts or legumes, therefore limiting the child’s gut microbiome diversity.
Bacteria in the gut can use nutrients from fiber to
increase nutrient absorption in the small intestine.
help heal inflammation within the gut.
synthesize vitamins such as Vitamin K.
increase the rate of digestion.
synthesize essential minerals such as iron (Fe).
As a generalization, college students are known for their eating habits being somewhat limited, relying on a lot of prepared and prepackaged foods. Why might this dietary strategy lead to digestive challenges, especially when they are under stress?
This type of diet decreases gut microbial diversity, allowing more pathogenic microbes to flourish.
This type of diet limits the kinds of nutrients taken into the body.
This type of diet increases the amount of stress hormones released in the body, and stress hormones cause digestive problems.
This type of diet decreases the amount of stress hormones released in the body, resulting in digestive problems.
This type of diet increases gut microbial diversity, allowing pathogenic microbes to grow more quickly.
How do beneficial microbes reduce intestinal inflammation?
They increase the rate of Vitamin K formation, which reduces inflammation.
They directly attack harmful bacteria through phagocytosis.
They secrete digestive enzymes that break down all food particles.
They increase the absorption of toxins in the intestine.
Choose the correct statement:
They do not secrete toxins that cause the breakdown of the intestinal mucus layer.
They decrease the amount of insulin secreted, which slows mucus layer breakdown.
They prevent short-chain fatty acids from being formed, thus reducing inflammation.
They decrease the rate of nutrient absorption, thereby preventing overuse of the intestine.
