Lect17-KR - Anaerobic respiration PMB/MCB 112 Respiration...

Info icon This preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Anaerobic respiration PMB/MCB 112 October 11, 2010
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Respiration , in the molecular sense, means passing electrons down an ETC and reducing an exogenous electron acceptor For almost all eukaryotes, that electron acceptor is oxygen But many bacteria can use alternative electron acceptors at the end of their electron transport chains This allows them to grow using respiration in the absence of oxygen
Image of page 2
Assimilative vs. dissimilative reduction In assimilative reduction , compounds are reduced for the purpose of building cellular macromolecules, and the cell only reduces the amount needed for growth Ex: NO 3 - reduced to –NH 2 groups SO 4 2- reduced to –SH groups In dissimilative reduction , compounds are reduced for the purpose of energy conservation, large amounts are reduced, and the cell excretes the reduced product into the environment Ex: NO 3 - reduced to NO 2 - , N 2 O or N 2 SO 4 2- reduced to HS-
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Anaerobic respiration systems 3) Methanogenesis CO 2 /CH 4 (-.23) 2) Ferric iron reduction 1) Nitrate reduction and denitrification 4) Perchlorate reduction ClO 4 - /Cl - E 0 ’ = 1.29 V
Image of page 4
Populations of microbes with different metabolic capacity occupy different regions of lakes and wetlands
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Denitrification is the conversion of nitrite into gaseous compounds that are lost from the soil and water Nitrate reduction denitrification
Image of page 6
E. coli can use O 2 or NO 3 - as an electron acceptor Some ETC components are shared by both pathways. Nitrate is only reduced to nitrite by E. coli . This process is called nitrate reduction . Fewer protons are transferred out of the cell during nitrate reduction than during oxygen reduction. Fewer protons are also transferred out of the cell during nitrate reduction than during full denitrification (next slide).
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Paracoccus denitrificans and Pseudomonas stutzeri reduce nitrate to nitrogen gas (nitrate reduction plus denitrification) This pathway pumps more protons than nitrate reduction to nitrite, since protons are also extruded by the nitric oxide reductase
Image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern