Biology Exam
Chapter 18 - Microbiology
True/False
Indicate whether the statement is true or false.
____
1. If a researcher wanted to use rod-shaped bacteria in her experiment, she should use a type of bacilli.
____
2. Animals are dependent on bacteria for nitrogen compounds made biologically available through their
decomposition activities.
____
3. The strain of E. coli in your intestines can be very harmful to your health.
____
4. All antibiotic medicines are made of chemicals produced by fungi.
____
5. During conjugation two genetically identical daughter cells are produced.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. Which of the following actions would increase nutrient levels in farm soil?
a. adding various types of saprotrophs into the soil
b. increasing the amount of crops grown in the soil
c. adding natural predators, such as ladybugs, to keep pests away
d. increase the amount of water given to the crops
____
2. A scientist was trying to determine whether a virus that caused disease in dogs could be transmitted to
humans. Which research procedure was most likely chosen for this project?
a. Study the complete life cycle of the virus in detail.
b. Inject the viral DNA directly into human cells and observe the results.
c. Identify the receptors used on the dog cell and compare them to human cell receptors.
d. Use an electron microscope to determine the precise shape of the outer viral capsid.
Figure 18-2
Effects of increasing UV radiation dose on rates of infection by various agents.
____
3. What is the independent variable in this experiment producing Figure 18-2?
a. the types of diseases
c. the amount of radiation
b. the amount of time elapsed
d. the presence of DNA
____
4. What do the results shown in Figure 18-2 imply about prions (the causative agent of scrapie)?
a. Prions are indestructible disease agents.
b. Prions do not contain components that are vulnerable to UV radiation.
c. Prions are not living organisms.
d. Prions do not have a cell membrane that sheilds them against UV radiation.
____
5. Which of the following might display data similar to that of scrapie?
a. cancer cells
c. HIV virus
b. bacterial endospores
d. bacterial capsule
____
6. Bacterial chromosomes have been used extensively by researchers in many experiments. Which of the
following is the most likely explanation as to why bacterial DNA has been used so frequently?
a. They only have one pair of chromosomes.
b. The DNA has a simple arrangement.
c. There are many types of bacterial DNA.
d. Their DNA is contained in a capsule.
____
7. Until fairly recently, scientists did not think much life could live deep at the bottom of the ocean because no
light reaches there. However, discovery of ocean vents found thriving communities of tube worms, crabs, and
other organisms. Which type of bacteria is most likely responsible for starting the food chain in this
environment?
a. Photoautotrophs
c. anaerobic bacteria
b. obligate aerobes
d. chemoautotrophs
____
8. Prion diseases can be transmitted from human to human if the prions are physically able to move from one
host to the next. If many cases of prion diseases are not diagnosed, in which group of people should extra
caution be taken to avoid spread of the disease?
a. Butchers
c. ambulance drivers
b. Surgeons
d. family members
____
9. Scientists believe one way animals spread prion diseases is because they are fed food processed from animal
parts, called animal by-products. If you had to design laws to address this issue, which of the following
approaches would limit both the cost of the program and the risk of transmission?
a. To ban all animal by-product foods.
b. To require animals eat only plant products.
c. To ban the use of nervous system tissues in by-product foods.
d. To have all by-products thoroughly tested every time they are made.
Agricultural manure is a significant waste problem. Even though some of it can be used as fertilizer, it is
produced in excess. The manure not only has a foul odor, but contains pathogens, including harmful bacteria,
that enter the soil and water sources. Recently, a compound isolated from the thyme plant, called thymol, has
been used in farm feedlots where the manure accumulates. Thymol is a natural antiseptic (compound that kills
bacteria) and has proved effective in reducing both the odor and the levels of the harmful bacteria.
____ 10. In what other products do you think thymol could most likely be used in?
a. oven cleaner
c. body lotion
b. Mouthwash
d. furniture polish
Completion
Complete each statement.
1. Many forms of thermoacidophiles are obligate anaerobes, which means they cannot live in the presence of
____________________.
2. If a student wanted to develop an experiment on how bacteria attach to each other in colonies, she should
design her procedures based on the structure and functions of the ____________________.
3. An autotrophic bacteria that could live in the dark would be a ____________________.
4. The healthy and helpful types of bacteria that live in and on your body are called normal
____________________.
5. Metabolically,
need to consume organic material in order to obtain energy,
Short Answer
1. Compare and contrast a virus and bacterium. List 2 features unique to each and two that they share.
2. Describe the adaptations bacteria might have to live in an extreme habitat.
3. Why are viruses not considered to be living things?
4. Compare and contrast lytic cycle and lysogenic cycle.
5. What is the main feature that distinguishes Bacterial cells from other organisms in other kingdoms?
6. Where would an ideal environment be for a photoautotroph?
Problem
1. Bacteriophages are being investigated as an alternative to antibiotics for the treatment of bacterial diseases.
What benefits would you see in using bacteriophages over antibiotics?
Essay
1. Many people use composting as a way to recycle their food garbage. Composting works by mixing food
scraps, such as fruit peels, with soil and leaves. Over time, the food scraps become part of the soil. At what
part of this process do you think bacteria play an important role? Describe how you think composting works
and why it is beneficial to humans and the environment.
Microbiology
Answer Section
TRUE/FALSE
1. ANS: T
The bacilli, as their name suggests, are rod-shaped bacteria.
PTS: 1
DIF: Bloom's Level C | DOK 2-MOD
REF: 519
STA: 1.1.6.a
TOP: 18-2
2. ANS: F
It is through nitrogen fixation that nitrogen is made biologically available; decomposition recycles nitrogen
compounds.
PTS: 1
DIF: Bloom's Level C | DOK 1-LOW
REF: 523
NAT: LS_4a
STA: 1.3.10.a
TOP: 18-3
3. ANS: F
The harmful strain of E. coli is different than the one in human intestines.
PTS: 1
DIF: Bloom's Level B | DOK 1-LOW
TOP: 18-3
4. ANS: F
Many types of antibiotics are compounds produced by bacteria.
REF: 523
PTS: 1
DIF: Bloom's Level B | DOK 1-LOW
TOP: 18-3
5. ANS: F
Halophiles are found in hypersaline environments.
REF: 523
PTS: 1
TOP: 18-1
DIF: Bloom's Level A | DOK 1-LOW
REF: 517
MULTIPLE CHOICE
1. ANS: A
Detrivores are decomposers that return nutrients to the soil by breaking down dead organic matter.
Feedback
A
B
C
D
That's right!
That would use up more nutrients!
Do pests use up nutrients?
Does water contain nutrients?
PTS: 1
DIF: Bloom's Level F | DOK 3-MOD
REF: 522
NAT: LS_4b
STA: 1.3.10.a
TOP: 18-3
2. ANS: C
Viruses can infect host cells only if they can bind to specific receptor cells.
Feedback
A
B
C
D
This is a good start, but will it answer the question?
What steps are missing here?
You are highly intelligent!
Not a bad idea, but...
PTS: 1
DIF: Bloom's Level F | DOK 3-MOD
REF: 527
TOP: 18-5
3. ANS: C
The changes observed in the levels of the infectious agents were a result of increasing amounts of UV
radiation.
Feedback
A
B
C
D
Are you sure?
Was time a factor on the graph?
Correct!
Try again...
PTS: 1
DIF: Bloom's Level D | DOK 3-MOD
REF: 531
NAT: IS_1b
STA: 2.1.2.b
TOP: 18-6
4. ANS: B
The disease agents tested are of varying complexity and contain different types of components. Bacteria are
complex living cells containing many types of compounds. Bacteriophages are virus particles, containing only
DNA and protein. Prions, as is now known, consist only of protein. The results imply that prions lack a
component that makes them vulnerable to the destructive action of the UV radiation.
Feedback
A
B
C
D
This statement is too general for the observed results. Only UV radiation is being tested.
That's right!
Bacteriophages, a type of virus, are not living organisms either.
Bacteriophages do not have a membrane either.
PTS: 1
DIF: Bloom's Level F | DOK 3-MOD
REF: 531
NAT: IS_1e
STA: 2.1.3.c
TOP: 18-4
5. ANS: B
Endospores can withstand extreme conditions, including high levels of UV radiation.
Feedback
A
B
C
D
Radiation is usually used to treat cancer.
Right!
The virus would likely respond like the phage.
This is a part of typical bacterial cells.
PTS: 1
DIF: Bloom's Level C | DOK 3-MOD
REF: 521
TOP: 18-2
6. ANS: B
The circular form of the DNA makes it easy to study and manipulate in experiments, including the
often-present plasmid.
Feedback
A
B
C
D
Is that true?
Very good!
Sounds good...but try again!
Check your definitions!
PTS: 1
TOP: 18-2
7. ANS: D
DIF: Bloom's Level D | DOK 3-MOD
REF: 518
Feedback
A
B
C
D
Doesn't "photo" mean light?
Check back to page 521.
Try again...
Yes!
PTS: 1
DIF: Bloom's Level D | DOK 3-MOD
REF: 521
TOP: 18-2
8. ANS: B
Prions infect the brain. Therefore the group that is most likely to be exposed to the brain are the surgeons in
human-to-human transmission.
Feedback
A
B
C
D
Would they be in contact with prions in humans?
Absolutely.
They are not likely to work on the brain...
What part of the body do prions infect?
PTS: 1
DIF: Bloom's Level F | DOK 3-MOD
REF: 531
TOP: 18-6
9. ANS: C
Prions are contained within the nervous system and brain. If these parts are removed from the food chain, this
would provide the minimal solution to transmitting the disease agents.
Feedback
A
B
C
D
You are looking for the minimal solution.
You are looking for the minimal solution.
Yes, this would be the smallest change that would have an impact on the transmission
rates.
This would involve too much effort.
PTS: 1
DIF: Bloom's Level E | DOK 3-MOD
REF: 531
TOP: 18-6
10. ANS: B
Mouthwash is the correct answer because many types of bacteria are found in the mouth. The purpose of
using mouthwash is to reduce the numbers of these bacteria.
Feedback
A
B
C
D
Are you sure?
You got it!
What is the purpose of lotion?
Try again...
PTS: 1
TOP: 18-3
DIF: Bloom's Level E | DOK 3-MOD
REF: 524
DIF: Bloom's Level B | DOK 2-MOD
TOP: 18-1
REF: 517
PTS: 1
DIF: Bloom's Level C | DOK 3-MOD
STA: 1.3.8.a
TOP: 18-2
3. ANS: chemoautotroph
REF: 518
PTS: 1
TOP: 18-1
4. ANS: flora
DIF: Bloom's Level B | DOK 2-MOD
REF: 521
PTS: 1
TOP: 18-3
DIF: Bloom's Level A | DOK 1-LOW
REF: 523
COMPLETION
1. ANS: oxygen
PTS: 1
STA: 1.3.8.c
2. ANS: pilus
SHORT ANSWER
1. ANS:
A provirus is a DNA virus that has been inserted into a host-cell chromosome. A retrovirus is an RNA virus
that contains the enzyme reverse transcriptase, which copies viral RNA into DNA.
PTS: 1
DIF: Bloom's Level B | DOK 2-MOD
REF: 527 | 530
TOP: 18-5
2. ANS:
Answers may include: The bacteria should be able to reproduce quickly and live in the environment. The
bacteria may also utilize substances that other organisms cannot use. They may have protective structures,
such as capsules or endospores.
PTS: 1
DIF: Bloom's Level C | DOK 3-MOD
REF: 517
STA: 1.3.9.b
TOP: 18-1
3. ANS:
Viruses do not carry out respiration, grow, or move. They can reproduce, but only when they are inside a
living cell.
PTS: 1
TOP: 18-4
DIF: Bloom's Level B | DOK 2-MOD
REF: 525
4. ANS:
Both are viral reproductive cycles. In a lytic cycle, the virus causes the destruction of the host cell. In the
lysogenic cycle, the viral DNA becomes integrated into the host cell's chromosome, after which it is passed
on to future generations of the host cell.
PTS: 1
DIF: Bloom's Level B | DOK 2-MOD
REF: 528
TOP: 18-5
5. ANS:
Rapid reproduction and simplicity of the cell have allowed bacteria to adapt to extreme environmental
conditions. They may utilize poisonous substances, be anaerobic, and live in low pH environments.
PTS: 1
DIF: Bloom's Level A | DOK 3-MOD
STA: 1.3.9.b
TOP: 18-2
6. ANS:
Viruses are not living things.
PTS: 1
NAT: LS_3e
DIF: Bloom's Level C | DOK 2-MOD
TOP: 18-4
REF: 517–519
REF: 525
PROBLEM
1. ANS:
Bacteriophages would probably be specific to only one kind of bacteria—the disease-causing strain.
Bacteriophages might be able to evolve to counteract the evolution of resistance by bacteria.
PTS: 1
STA: 3.1.3.e
DIF: Bloom's Level F | DOK 3-MOD
TOP: 18-5
REF: 526 | 527
ESSAY
1. ANS:
Possible answer: Food scraps are made of nutrients that can be reused and recycled. When the food scraps are
mixed in with soil, decomposers from the soil (certain types of bacteria), start breaking down the food scraps.
Nutrients are then returned to the earth and become part of the soil, enriching it in the process. This is
beneficial to humans and the environment because it reduces the amount of waste produced that must be
removed and handled, and also provides a way to fertilize soil allowing plants to grow better.
Score Description
Student describes the point at which bacteria play an important role in composting,
4
clearly describes how composting works, and discusses several benefits to humans
and the environment.
Student describes the point at which bacteria play an important role in composting,
3
describes how composting works, and discusses one benefit to humans and the
environment.
Student explains how composting works and its benefits, but does not discuss where
2
bacteria are a part of the process.
Student explains how composting works.
1
OR
Student explains the benfits of composting.
Student’s response is totally incorrect or irrelevant.
0
Blank
No student response.
PTS: 1
NAT: LS_4b
DIF: Bloom's Level E | DOK 3-MOD
STA: 1.3.10.a
TOP: 18-3
REF: 522