Ch. 13: Biogeochemical Cycles

Question 1

Select the correct choice for the abundances of elements found in cells, from lowest to highest.

* sulfur, phosphorus, nitrogen, and oxygen
* carbon, nitrogen, oxygenm a

Answer 1

sulfur, phosphorus, nitrogen, and oxygen

Question 2

Select the correct choice for the abundances of elements found in cells, from highest to lowest.

* carbon, nitrogen, oxygen, and sulfur
* carbon, potassium, and phosphor

Answer 2

carbon, oxygen, nitrogen, and sulfur

Question 3

Elemental movement between reservoirs is termed:

* flux
* reduction
* sink
* source
* oxidation

Answer 3

flux

Question 4

Why is CO2 considered a greenhouse gas?

* it absorbs heat attempting to escape the atmosphere
* it is used by su

Answer 4

it absorbs heat attempting to escape the atmosphere

Question 5

Which of these statements is TRUE regarding methanogenesis?

* it is an anaerobic process carried out by Eukarya
* it is an aerobic p

Answer 5

it is an anaerobic process carried out by Archaea

Question 6

In methane-producing environments large polymers are broken down by a consortium fo microbes. This consortium includes:

* sulfate-reducing microbes and methanogens
* obligate aerobic bacteria

Answer 6

polymer hydrolyzing microbes, fermenters, and methanogens

Question 7

Whihc is the major nitrogen reservoir on Earth?

* the atmosphere
* plants
* organic matter in soil
* ocean biomass
* mci

Answer 7

the atmosphere

Question 8

Which of these summarizes the overall process of nitrogen fixation?

* ammonia -> NO3-
* ammonia -> N2
* NO3- -> biomass
* NO3- -> N2
* N2 ->

Answer 8

N2 -> biomass

Question 9

Which of these summarizes the over reaction for nitrification?

* NO3- -> NO2-
* NO2- -> NO3-
* ammonia -> NO3-
* NO3- -> N2
* NO3- -> a

Answer 9

ammonia -> NO3-

Question 10

Which of these summarizes the overall process of denitrification?

* N2 -> NH3
* NO3- -> N2
* NO3- -> ammonia -> biomass
* biomass -> ammon

Answer 10

NO3- -> N2

Question 11

Whihc one of the following is NOT a reservoir for oxygen?

* water
* nitrate
* ammonia
* carbon dioxide
* the atmosphere

Answer 11

ammonia

Question 12

Atmospheric sulfur is primarily present as

* elemental sulfur
* H2S
* dimethylsulfoniopropionate
* the amino acid c

Answer 12

H2S

Question 13

Aquatic sulfur is primarily present as

* sulfate
* dimethylsuloniopropionate
* H2S
* the amino acid cysteine
*

Answer 13

sulfate

Question 14

Which microbes are directly responsible for methane production? (select ALL that apply)

* hydrogenotrophic methanogens
* homoacetogens
* secondary fermenters
*

Answer 14

hydrogenotropic methanogens and acetotrophic methanogens

Question 15

T/F:

CO2 is a greenhouse gas.

Answer 15

True

Question 16

T/F:

Methanogenesis helps drive a number of other microbial processes in anaerobic environments through the removal of hydrogen gas.

Answer 16

True

Question 17

T/F:

The process of denitrification is an anaerobic process.

Answer 17

True

Question 18

An interacting community of interdependent organisms is called a/an __.

Answer 18

consortium

Question 19

The chemoautotrophic process that results in the oxidation of ammonia to nitrate is called __.

Answer 19

nitrification