魅影直播

Calculate the change in free energy for the transit of two electrons from the quinone pool to cytochrome c₂ in purple bacterial photosynthetic electron transport. Assume that the reduction potential of cytochromec₂is similar to those of other c-type cytochromes.

What chloroplast protein is the functional counterpart of mitochondrial cytochrome c?

Estimate the change in free energy whenundergoes photooxidation.

Calculate $\mathit{螖}{\mathit{蔚}}^{\mathbf{0}\mathbf{\text{'}}}$and $\mathit{螖}{\mathit{G}}^{\mathbf{0}\mathbf{\text{'}}}$for the light reactions in plants, that is, the four-electron oxidation of H₂O by NADP⁺.

Compare and contrast photophosphorylation and oxidative phosphorylation.

Although the net equation for photosynthesis indicates that the process can be measured in terms of either ${\mathbf{O}}_{\mathbf{2}}$produced or ${\mathbf{CO}}_{\mathbf{2}}$ fixed, in practice, these measurements are not necessarily equivalent. Explain.

Why is it possible for chloroplasts to absorb much more than 8鈥�10 photons per ${\mathbf{O}}_{\mathbf{2}}$ molecule evolved?

Predict the effect of adding myxothiazol, an inhibitor of electron transport in mitochondrial Complex III, to a suspension of chloroplasts exposed to light. Would either $\mathbf{ATP}$or$\mathbf{NADPH}$ production be affected?

Explain the relationship between the light and dark reactions.

Why would 鈥渒nocking out鈥� a gene for a chloroplast fatty acid desaturase (an enzyme involved in synthesizing fatty acids containing threedouble bonds) increase the rate of photosynthesis at $\mathbf{40}\mathbf{掳}\mathbf{C}\mathbf{,}$ a temperatureat which photosynthesis is normally impaired?