Chapter Questions
Respiration contains the Latin word root spiro, which means "to breathe." Why is the process described in this chapter called cellular respiration? What might your answer indicate about what scientists already knew when they first observed cellular respiration?
All steps of cellular respiration are closely connected. Describe the problems that would occur if glycolysis, the Krebs cycle, or the electron transport chain were not working.
How does aerobic respiration yield so much ATP from each glucose molecule, compared with glycolysis alone?
How might a mitochondrion's double membrane make cellular respiration more efficient than if it had a single membrane?
Health-food stores sell a product called "pyruvate plus," which supposedly boosts energy. Why is this product unnecessary? What would be a much less expensive substitute that would accomplish the same thing?
you apply one or more poisons described in this chapter's Apply It Now box, how does your answer change?In a properly functioning mitochondrion, is the pH in the matrix lower than, higher than, or the same as the pH in the intermembrane space? If
Describe the energy pathways that are available for cells living in the absence of $\mathrm{O}_{2}$
A chemical works as a disinfectant by poking holes in bacterial cell membranes. Why would this stop the cells from making ATP? Why would the inability to make ATP kill a cell?
Some types of beer are bottled with yeast. These beers are not carbonated at bottling, but if you open them a few weeks later they will bubble. Explain the source of this carbonation.
Describe how aerobic respiration occurs in bacteria. How does this relate to how aerobic respiration occurs in mitochondria? Explain the relationship between bacteria and mitochondria.
Under what conditions might your cells shift from aerobic respiration to fermentation? In what habitats might an organism rely solely on fermentation?
Compare the number of ATP molecules required to produce one glucose molecule in photosynthesis (see figure 5.9 ) with the number of ATP molecules generated per glucose in aerobic respiration (see figure 6.8 ). How do these numbers compare to the ATP yield from fermentation?