Nitrogen cycling (lec 8)

Question 1

the main components of the nitrogen cycle

Answer 1

• be able to draw

-

Question 2

the different types of bac that play essential roles in each part of the cycle

Answer 2

-

Question 3

symbiotic relationships that allow for nitrogen cycling

Answer 3

• plants and bacteria ( protection for nitrogen ect)
• nitrogonase is oxygen sensitive ( must be in anaerobic environment) , bacteria uses it to fix nitrogen but has evolved to protect it from denaturing

Question 4

how is availability of nitrogen tied to carbon use

Answer 4

• it cant assimilate nitrogen if carbon is not around

Question 5

What forms of nitrogen are usable by living organisms

Answer 5

-nitrate or amnonium

Question 6

assimilation nitrate reduction

Answer 6

• formtion of organic nitrogen
• assimilation : mineralization ,
  ie Amino acids is an assimilated forms of nitrogen

Question 7

assimilation nitrate reduction

Answer 7

• formtion of organic nitrogen
• assimilation : mineralization
  ie Amino acids is an assimilated forms of nitrogen

Question 8

why is the nitrogen cycle so important?

Answer 8

see previous lecture

• bacteria are the only organism able to fix nitrogen
• alot of organism needs nucleic acids and amino acids which require nitrogen
• closely linked to the use of carbon

Question 9

how has earth maintained conditions favourable for life?

Answer 9

see previous lecture

Question 10

What are the main areas of study in the nitrogen cycle and what does each mean (why are each important) ?

Answer 10

• look in lab 5

Question 11

what is a potential problem with nitrification ?

Answer 11

-requires alot of energy –> the insensitive to do it must be high
-nh3–> no3—> n2 ( N2 can be lost seeing as it is a gas)
no3- –> no2- they both leach
removes usable form of nitrogen from plant use

Question 12

in a well fetilized agricultural soil environment where there is a limited number of nirogen fixing microbes. what specifically canbacteria do to ensure constant supplies of ammnoia, what are the products of this reaction., and what how do the bacteria utilize these products

Answer 12

• urea, ammonia and ammonuim,
• ## No3- reduced to ammonia

Question 13

what will bacteria due with nitrogen already found in the environment

Answer 13

-

Question 14

the use of oxygen as a terminal electron acceptor provides the most energy for bacterial growth, however, nitrogen fixation must be performed under anaerobic conditions. Explain carefully mwhy this is the case adn indicate how bacteria can get around this confusing situation.

Answer 14

-