Cellular Biology

Question 1

A fresh wastewater sample containing nitrate ions, sulfate ions, and dissolved oxygen is taken and placed into a sealed jar absent of air. What is the sequence of oxidation of the compounds?

Answer 1

Dissolved oxygen, nitrate, and then sulfate

Question 2

Obnoxious odors will:

Answer 2

Appear in the sample when the dissolved oxygen and nitrate are exhausted

Question 3

Bacteria will convert ammonia to nitrate if the bacteria are:

Answer 3

Autotrophic

Question 4

Bacteria will generally reduce nitrate to nitrogen gas only if the bacteria are:

Answer 4

Facultative heterotrophic

Question 5

A bacteriophage is a

Answer 5

Virus that infects bacteria

Question 6

Algal growth in the wastewater:

Answer 6

Will be inhibited when the dissolved oxygen is exhausted and will be inhibited when toxins are found in the solution.

Question 7

In the presence of nitrifying bacteria, nontoxic inorganic compounds and sunlight, algal growth in the wastewater sample will be:

Answer 7

Inhibited

Question 8

The addition of protozoa to the wastewater will:

Answer 8

Decrease the growth of algae and bacteria in the wastewater

Question 9

Coliform bacteria in wastewater from human, animal, or soil sources

Answer 9

Can be categorized into only two groups: human/animal and soil

Question 10

The major pathways of exposure to toxic agents are:

Answer 10

Inhalation, ingestion, and skin absorption

Question 11

LD50 means the dose in

Answer 11

mg/kg body mass at which 50% of the test animals died

Question 12

Chemical A has an LD50 of 3 mg/kg. Chemical B has an LD50 of 9 mg/kg. Chemical A is

Answer 12

Three times as toxic as chemical B

Question 13

The law of additive effects

Answer 13

Applies only when the effects from the components gases and vapors occur within the same organs.