Microbiology help please by midnight tonight!?

Question

You have isolated a bacterium that grows in a medium containing only inorganic nutrients. Ammonia is oxidized to nitrate ion. This bacterium is (blank)?
Please pick from choices below and why you picked that one.
Thanks in advance for your help.
a) gram-negative
b) using anaerobic respiration
c) a chemoautotroph
d) a photoautotroph
e) a photoheterotroph

Answer 1

This is discussed on the same website provided in your previous question:

http://helios.bto.ed.ac.uk/bto/microbes/nitrogen.htm

The site says: "The term nitrification refers to the conversion of ammonium to nitrate (pathway 3-4). This is brought about by the nitrifying bacteria, which are specialised to gain their energy by oxidising ammonium, while using CO2 as their source of carbon to synthesise organic compounds. Organisms of this sort are termed chemoautotrophs - they gain their energy by chemical oxidations (chemo-) and they are autotrophs (self-feeders) because they do not depend on pre-formed organic matter."

So it's C.

I'm telling you - if you have more nitrogen cycle questions, save your Yahoo question points and look on that site. It's easy to understand and seems to be pretty complete.

Answer 2

C but look at it another way. No organic molecules therefore no food. Therefore they must be an autotroph. Only cynobacteria (bluegreen algae)are phototrophic, and they would use nitrates or in the case of Nostoc convert Nitrogen gas to nitrates.

They can not be heterotrophic because no organic matter to eat.


You do not have enough clues to determine gram negative or positive and anaerobic respiration requires an organic compound to break down for energy.

That leaves C

Answer 3

agree with norcekri. take a look at the previously posted question and my reply there-
google and wikipedia are generally good places to start your searches, if your text books can't define things clearly. Good luck and remember you wont have us around to lend the answers on quizes or tests in a classroom setting- so even if this is a "take-home" version of such, in the long run you'll be better off knowing it yourself. God Bless and Peace.

Answer 4

I suggest that you look up the five terms and see which one describes an organism that needs only inorganic sustenance. That way, you'll know all five terms for the test.

Answer 5

b