Exam 14: Energy Generation in Mitochondria and Chloroplasts

Which of the following is not an electron carrier that participates in the electron-transport chain?

What are the major molecules that need to be transported into and out of the mitochondrion to keep the citric acid cycle, electron-transport chain, and ATP synthesis going?

Which of the following statements describes the mitochondrial intermembrane space?

Osmosis describes the movement of water across a biological membrane and down its concentration gradient.In chemiosmosis, useful energy is harnessed by the cell from the movement of __________ across the inner mitochondrial membrane into the matrix __________ a concentration gradient.

Based upon what you know about metabolism, explain how electrons are stripped from food molecules and used to drive the electron-transport chain.

The enzyme ribulose bisphosphate carboxylase (Rubisco) normally adds carbon dioxide to ribulose 1,5-bisphosphate.However, it will also catalyze a competing reaction in which O₂ is added to ribulose 1,5-bisphosphate to form 3-phosphoglycerate and phosphoglycolate.Assume that phosphoglycolate is a compound that cannot be used in any further reactions.If O₂ and CO₂ have the same affinity for Rubisco, which of the following is the lowest ratio of CO₂ to O₂ at which a net synthesis of sugar can occur?

Modern eukaryotes depend on mitochondria to generate most of the cell's ATP.How many molecules of ATP can a single molecule of glucose generate?

The respiratory chain is relatively inaccessible in the experimental manipulation of intact mitochondria.After disrupting mitochondria with ultrasound, however, it is possible to isolate functional submitochondrial particles, which consist of broken cristae that have resealed inside-out into small, closed vesicles.In these vesicles, the components that originally faced the matrix are now exposed to the surrounding medium. A.How might such an arrangement aid in the study of electron transport and ATP synthesis? B.Consider an anaerobic preparation of such submitochondrial particles.If a small amount of oxygen is added, do you predict that the preparation will consume oxygen in respiration reactions? Will the medium outside the particles become more acidic or more basic? What, if anything, will change if the flow of protons through ATP synthase is blocked by an inhibitor? Explain your answer.

Oxidative phosphorylation, as it occurs in modern eukaryotes, is a complex process that probably arose in simple stages in primitive bacteria.Which mechanism is proposed to have arisen first as this complex system evolved?

Electron transport is coupled to ATP synthesis in mitochondria, in chloroplasts, and in the thermophilic bacterium Methanococcus.Which of the following is likely to affect the coupling of electron transport to ATP synthesis in ALL of these systems?

If you shine light on chloroplasts and measure the rate of photosynthesis as a function of light intensity, you get a curve that reaches a plateau at a fixed rate of photosynthesis, x, as shown in Figure 14-41. Figure 14-41 Which of the following conditions will increase the value of x?

Experimental evidence supporting the chemiosmotic hypothesis was gathered by using artificial vesicles containing a protein that can pump protons in one direction across the vesicle membrane to create a proton gradient.Which protein was used to generate the gradient in a highly controlled manner?