细胞能量转换

Japan researcher, Nature 386: 300, 1997.
❖ The ATP synthase is a reversible coupling device
❖ Other roles for the proton-motive force in addition to ATP synthase
F1: 5 subunits in the ratio 3:3:1:1:1
F0: 1a：2b：12c
❖F1 particles have ATP synthase activity
❖ Proton translocation through F0 drives ATP synthesis by F1: Binding Change Model and rotational catalysis
Electron transport Oxidative phosphorylation Metabolite transport
Maห้องสมุดไป่ตู้rix
Intermembrane space
Pyruvate oxidation TCA cycle ßoxidation of fats
Nucleotide phosphorylation
B. Molecular basis of phosphorylation: ATP synthase
❖ The structure of the ATP synthase
F1 particle is the catalytic subunit; The F0 particle attaches to F1 and is embedded in the inner membrane.
三羧酸循环：底物水平的磷酸化产生（线粒体）2ATP； 产生 6NADH（线粒体），生成 18ATP； 产生 2FADH2（线粒体），生成 4 ATP
总计生成 36或38 ATP
3. Chloroplast and photosynthesis
A. Comparison of a mitochondrion and a chloroplast.
As electrons move through the electron-transport chain, H+ are pumped out across the inner membrane, and form Proton motive force;
Electrons move through the inner membrane via a series of carriers of decreasing redox potential
More than 21026 molecules (>160kg) of ATP per day in our bodies.
Electrons pass from NADH or FADH2 to O2, the terminal electron acceptor, through a chain of carriers in the inner membrane (FMN, Fe-S center, Heme group Fe, CoQ);
Chapter 7
Energy Generation in Mitochondria and Chloroplasts
(1) Mitochondria: in all eukaryotic cells The relationship between the structure and function of mit.
DNA replication, RNA transcription,
Protein translation
2. Molecular basis of oxidative phosphorylation
A. Molecular basis of oxidation: Electrontransport chain
生物氧化产生ATP的统计
一个葡萄糖分子经过细胞呼吸全过程产生多少ATP？
糖酵解：底物水平磷酸化产生 4 ATP（细胞质） 己糖分子活化消耗 2 ATP（细胞质） 产生 2NADH，经电子传递产生 4或 6 ATP
（线粒体）净积累 6或8 ATP
丙酮酸氧化脱羧：产生 2NADH（线粒体），生成 6ATP
Figure 7-26 An experiment demonstrating that the ATP synthase is driven by proton flow. By combining a lightdriven bacterial proton pump (bacteriorhodopsin), an ATP synthase purified from ox heart mitochondria, and phospholipids, vesicles were produced that synthesized ATP in response to light.
Figure 14-6 Fractionation of purified mitochondria into separate components. These techniques have made
it possible to study the different proteins in each mitochondrial compartment. The method shown, which allows the processing of large numbers of mitochondria at the same time, takes advantage of the fact that in media of low osmotic strength water flows into mitochondria and greatly expands the matrix space (yellow). While the cristae of the inner membrane allow it to unfold to accommodate the expansion, the outer membranewhich has no folds to begin withbreaks, releasing a structure composed of only the inner membrane and the matrix.
Figure 7-4 Relationship between mitochondria and microtubules.
Figure 7-3 Mitochondrial plasticity. Rapid changes of shape are observed when a mitochondrion is visualized in a living cell.
Localization of metabolic functions within the mitochondrion
Outer membrane:
Phospholipid synthesis fatty acid desaturation Fatty acid elongation
Inner membrane:
Figure 7-5 Localization of mitochondria near sites of high ATP utilization in cardiac muscle and a sperm tail.
❖Inner and outer mitochondrial membranes enclose two spaces: the matrix and intermembrane space.
C. Mithchell’s Chemiosmotic theory (1961)
❖The pH and electrical gradient resulting from transport of protons links oxidation to phosphorylation. ❖When electrons are passed to carriers only able to accept electrons, the H+ is translocated across the inner membrane.
(1) Electron-transport chain: Carry out oxidation reactions; (2) ATP synthase: Makes ATP in the matrix; (3) Transport proteins: Allow the passage of metabolites
1. Mitochondria and oxidative phosphorylation A. Mitochondrial structure and function
❖The size and number of mitochondria reflect the energy requirements of the cell.
Figure 14-39 The chloroplast. This photosynthetic organelle contains three
distinct membranes (the outer membrane, the inner membrane, and the thylakoid membrane) that define three separate internal compartments (the intermembrane space, the stroma, and the thylakoid space). The thylakoid membrane contains all of the energy-generating systems of the chloroplast. In electron micrographs this membrane appears to be broken up into separate units that enclose individual flattened vesicles (see Figure 14-40), but these are probably joined into a single, highly folded membrane in each chloroplast. As indicated, the individual thylakoids are interconnected, and they tend to stack to form aggregates called grana.