1. Bacteria and Archaea

2. Prokaryotes lack the nucleus found in eukaryotic cells
Prokaryotes lack the nucleus found in eukaryotic cells. As a result, prokaryotic cells do not contain which of the following?
a nuclear membrane
DNA
one or more chromosomes
all of the above
Answer: a

3. Prokaryotes lack the nucleus found in eukaryotic cells
Prokaryotes lack the nucleus found in eukaryotic cells. As a result, prokaryotic cells do not contain which of the following?
a nuclear membrane
DNA
one or more chromosomes
all of the above 3

4. Which of the following statements best describes most bacteria?
They are generally harmful.
They are limited to living in a few habitats.
They are very common in the environment.
They are responsible for the “common cold.”
Answer: c 4

5. Which of the following statements best describes most bacteria?
They are generally harmful.
They are limited to living in a few habitats.
They are very common in the environment.
They are responsible for the “common cold.” 5

6. Which of the following statements about biofilms is incorrect?
Growth is due to signaling molecules recruiting cells.
Cells secrete sticky proteins and polysaccharides.
Damage to industrial equipment costs billions.
Nutrients and wastes travel through channels.
They are uncommon in nature.
Answer: e

7. Which of the following statements about biofilms is incorrect?
Growth is due to signaling molecules recruiting cells.
Cells secrete sticky proteins and polysaccharides.
Damage to industrial equipment costs billions.
Nutrients and wastes travel through channels.
They are uncommon in nature.

8. In what type of environment would you find extreme halophiles living?
ice
hot springs
very salty water
anoxic swamps
Answer: c 8

9. In what type of environment would you find extreme halophiles living?
ice
hot springs
very salty water
anoxic swamps 9

10. Which of the following gets its energy from sunlight and its carbon from ingesting other organisms?
photoautotroph
chemoautotroph
photoheterotroph
chemoheterotroph
Answer: c 10

11. Which of the following gets its energy from sunlight and its carbon from ingesting other organisms?
photoautotroph
chemoautotroph
photoheterotroph
chemoheterotroph 11

12. Scientific Skills Exercises
Sugar beet seeds were planted in separate pots, with 32 seeds in each of five soil treatments. The pots were inoculated with Rhizoctonia solani and placed in greenhouses kept at 20°C with a 16-hour light: 8-hour dark cycle. After 20 days, the percentage of infected sugar beet seedlings was determined for each soil treatment. The results of the experiment are shown in the table.

13. What hypothesis were the researchers testing in this study?
Growth is due to signaling molecules recruiting cells.
Cells secrete sticky proteins and polysaccharides.
Damage to industrial equipment costs billions.
Nutrients and wastes travel through channels.
They are uncommon in nature.
Answer: d

14. What hypothesis were the researchers testing in this study?
Growth is due to signaling molecules recruiting cells.
Cells secrete sticky proteins and polysaccharides.
Damage to industrial equipment costs billions.
Nutrients and wastes travel through channels.
They are uncommon in nature.

15. What is the independent variable in this study?
soil treatment
percentage of seedlings with fungal disease
number of seeds in each soil treatment
Answer: a

16. What is the independent variable in this study?
soil treatment
percentage of seedlings with fungal disease
number of seeds in each soil treatment

17. What is the dependent variable in this study?
soil treatment
percentage of seedlings with fungal disease
number of seeds in each soil treatment
Answer: b

18. What is the dependent variable in this study?
soil treatment
percentage of seedlings with fungal disease
number of seeds in each soil treatment

19. How did the researchers provide replication within this experiment?
After they obtained the results described above, they asked other scientists to repeat the experiment two more times.
They planted 32 sugar beet seeds for each soil treatment.
They set up five different soil treatments.
Answer: b

20. How did the researchers provide replication within this experiment?
After they obtained the results described above, they asked other scientists to repeat the experiment two more times.
They planted 32 sugar beet seeds for each soil treatment.
They set up five different soil treatments.

21. Which is a controlled variable from the experiment?
the amount of light the plants were exposed to
the number of plants per treatment
percentage of seedlings with fungal disease
the amount of disease-suppressive soil the plants were grown in
Answer: a

22. Which is a controlled variable from the experiment?
the amount of light the plants were exposed to
the number of plants per treatment
percentage of seedlings with fungal disease
the amount of disease-suppressive soil the plants were grown in

23. A graphical representation of the data is shown
A graphical representation of the data is shown. The researchers concluded that microorganisms were responsible for the disease-suppressive properties of the soil.

24. How do the results shown in the figure on the previous slide support this conclusion?
The lowest rate of fungal infection was found in seedlings grown in disease-suppressive soil.
A high rate of fungal infection was found in seedlings grown in soil from the margin of the field.
Fungal infection rate increased in seedlings grown in disease-suppressive soil that had been heated.
Fungal infection rate decreased in seedlings grown in soil from the margin of the field mixed with disease- suppressive soil.
Answer: c

25. How do the results shown in the figure on the previous slide support this conclusion?
The lowest rate of fungal infection was found in seedlings grown in disease-suppressive soil.
A high rate of fungal infection was found in seedlings grown in soil from the margin of the field.
Fungal infection rate increased in seedlings grown in disease-suppressive soil that had been heated.
Fungal infection rate decreased in seedlings grown in soil from the margin of the field mixed with disease- suppressive soil.

26. Which of the following results would have disproved the hypothesis that microorganisms are responsible for the disease-suppressive properties of soils?
if seedlings had similar fungal infection rates when grown in heated and unheated disease-suppressive soil
if seedlings had similar fungal infection rates when grown in disease-suppressive soil and soil from the margin of the field
if seedlings had similar fungal infection rates when grown in 100% and 10% disease-suppressive soil
No results could have disproved the hypothesis that microorganisms are responsible for the disease- suppressive properties of soil.
Answer: a

27. Which of the following results would have disproved the hypothesis that microorganisms are responsible for the disease-suppressive properties of soils?
if seedlings had similar fungal infection rates when grown in heated and unheated disease-suppressive soil
if seedlings had similar fungal infection rates when grown in disease-suppressive soil and soil from the margin of the field
if seedlings had similar fungal infection rates when grown in 100% and 10% disease-suppressive soil
No results could have disproved the hypothesis that microorganisms are responsible for the disease- suppressive properties of soil.