slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
The Proton Motive Force PowerPoint Presentation
Download Presentation
The Proton Motive Force

Loading in 2 Seconds...

play fullscreen
1 / 17

The Proton Motive Force - PowerPoint PPT Presentation


  • 306 Views
  • Uploaded on

The transfer of H + through a proton pump generates an electrochemical gradient of protons, called a proton motive force . The Proton Motive Force. - It drives the conversion of ADP to ATP through ATP synthase. - This process is known as the chemiosmotic theory. Figure 14.5.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'The Proton Motive Force' - booker


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide2
The transfer of H+ through a proton pump generates an electrochemical gradient of protons, called a proton motive force.

The Proton Motive Force

- It drives the conversion of ADP to ATP through ATP synthase.

- This process is known as the chemiosmotic theory.

Figure 14.5

slide3
When protons are pumped across the membrane, energy is stored in two different forms:

- The electrical potential (Dy) arises from the separation of charge between the cytoplasm and solution outside the cell membrane.

- The pH difference (DpH) is the log ratio of external to internal chemical concentration of H+.

The relationship between the two components of the proton potential Dp is given by:

Dp = Dy – 60DpH

The Proton Motive Force

slide5
Besides ATP synthesis, Dp drives many cell processes including: rotation of flagella, uptake of nutrients, and efflux of toxic drugs.

Dp Drives Many Cell Functions

Figure 14.9

slide6
ETS proteins such as cytochromes associate electron transfer with small energy transitions, which are mediated by cofactors.

Energy transitions typically involve these kinds of molecular structures:

- Metal ions, such as iron or copper,held in place with amino acid residues

- Conjugated double bonds and heteroaromatic rings, such as the nicotinamide ring of NAD+/NADH

The Respiratory ETS

slide10
Animation: A bacterial electron transfer system

ETS

Click box to launch animation

slide11
The F1Fo ATP synthase is a highly conserved protein complex, made of two parts:

The F1Fo ATP Synthase

- Fo: Embedded in the membrane

- Pumps protons

- F1: Protrudes in the cytoplasm

- Generates ATP

Figure 14.17

slide13
Animation: ATP Synthase Mechanism

The F1Fo ATP Synthase

Click box to launch animation

slide14
Oxidized forms of nitrogen

- Nitrate is successively reduced as follows:

NO3– → NO2– → NO → 1/2 N2O → 1/2 N2

nitric oxide

nitrous oxide

nitrogen gas

nitrate

nitrite

- In general, any given species can carry out only

one or two transformations in the series.

Oxidized forms of sulfur

- Sulfate is successively reduced by many bacteria as follows:

SO42– → SO32– → 1/2 S2O32– → S0 → H2S

sulfur

hydrogen sulfide

sulfate

sulfite

thiosulfate

slide15
Anaerobic environments, such as the bottom of a lake, offer a series of different electron acceptors.

- As each successive TEA is used up, its reduced form appears; the next best electron acceptor is then used, generally by a different microbe species.

Figure 14.20

slide16
Lithotrophy is the acquisition of energy by oxidation of inorganic electron donors.

A kind of lithotrophy of great importance in the environment is nitrogen oxidation.

Lithotrophy

1/2 O2

O2

1/2 O2

NH4+ → NH2OH → HNO2 → HNO3

ammonium

hydroxylamine

nitric acid

(nitrate)

nitrous acid

(nitrite)

Surprisingly, ammonium can also yield energy under anaerobic conditions through oxidation by nitrite produced from nitrate respiration.

slide17
Hydrogenotrophy is the use of molecular hydrogen (H2) as an electron donor.

Hydrogenotrophy

-H2 has sufficient reducing potential to donate e– to nearly all biological electron acceptors.

- Including chlorinated organic molecules, via dehalorespiration

- Which has potential for bioremediation

Figure 14.24