Question 1: How do actryloside and bongkrekic acid affect mitochondrial respiration? What is the target of these molcules and how does it do what you think it does? Question 2: Why can proton ionophores be marketed as diet drugs and is it a good idea to take them?

When muscle cells run out of oxygen, what happens to the potential for energy extraction from sugars and what pathways do the cell use?

Figure 4.15 Cyanide inhibits cytochrome c oxidase, a component of the electron transport chain. If cyanide poisoning occurs, would you expect the pH of the intermembrane space to increase or decrease? What affect would cyanide have on ATP synthesis? Figure 4.15 (a) The electron transport chain is a set of molecules that supports a series of oxidation-reduction reactions. (b) ATP synthase is a complex, molecular machine that uses an H+ gradient to regenerate ATP from ADP. (c) Chemiosmosis relies on the potential energy provided by the H+ gradient across the membrane.

How Do Vitamin-Derived Coenzymes Aid Metabolism? What chemical functionality is provided to enzyme reactions by pyridoxal phosphate (we Chapter 13)? By coenzyme A (see Chapter I9)? By vitamin B12 (see Chapter 23)? By thiamine pyrophosphate (see Chapter 19)?

The Relative Efficiency of ATP Synthesis in Noncyclic versus Cyclic Photophosphorylation If noncyclic photosynthetic electron transport leads to the translocation of 7 H+/2e- and cyclic photosynthetic electron transport leads to the translocation of 2 H+/e-, what is the relative photosynthetic efficiency of ATP synthesis (expressed as the number of photons absorbed per ATP synthesized) for noncyclic versus cyclic photophosphorylation? (Assume that the CF1CF0-ATP synthase yields 3 ATP/14 H+.)

Figure 27.3 illustrates the response of R (ATP-regenerating) and U (ATP-utilizing) enzymes to energy charge. a. Would hexokinase be an R enzyme or a U enzyme? Would glutamine: PRPP amidotransferase, the second enzyme in purine biosynthesis, be an R enzyme or a U enzyme? b. If energy charge = 0.5: Is the activity of hexokinase high or low? Is ribose-5-P pyrophosphokinase activity high or low? c. If energy charge = 0.95: Is the activity of hexokinase high or low? Is ribose-5-P pyrophosphokinase activity high or low?

Which of the following reaction pathways is not part of the second stage of aerobic respiration? a. electron transfer phosphorylation b. acetyl-CoA formation c. Krebs cycle d. glycolysis e. a and d

The Overall Free Energy Change for Photosynthetic NADP+ Reduction What is the overall free energy change (G) for noncyclic photosynthetic electron transport? 4 (700-nm photons) + 4 (680-nm photons) + 2 H2O + 2 NADP+O2 + 2 NADPH + 2H+

Understanding the Mechanism of Hemolytic Anemia Genetic defects in glycolytic enzymes can have serious consequences for humans For example, defects in the gene for pyruvate kinase can result in a condition known as hemolytic anemia. Consult a reference to learn about hemolytic anemia, and discuss why such genetic defects lead to this condition.

Which of the following comparisons or contrasts between endergonic and exergonic reactions is false? Endergonic reactions have a positive ?G and exergonic reactions have a negative ?G Endergonic reactions consume energy and exergonic reactions release energy Both endergonic and exergonic reactions require a small amount of energy to overcome an activation barrier Endergonic reactions take place slowly and exergonic reactions take place quickly.