What process is producing the pressure?

Common baker’s yeast cells, Saccharomyces cerevisiae, were suspended in 5.0 mL of a 1 percent glucose solution in a 15-mL test tube (identified as tube A). A second identical tube was also prepared, but without the cells (tube B), and a third tube in which the cells were initially suspended in distilled water (tube C). After 3 minutes’ time, 2.0 mL of a 3 percent hydrogen peroxide solution was added to all three tubes, which were then sealed with a pressure sensor. Pressure data were collected at 30-s intervals for 5 min, at which time the tubes were unsealed and 2.0 mL of a 2N HCl solution... Show more

Common baker’s yeast cells, Saccharomyces cerevisiae, were suspended in 5.0 mL of a 1 percent glucose solution in a 15-mL test tube (identified as tube A). A second identical tube was also prepared, but without the cells (tube B), and a third tube in which the cells were initially suspended in distilled water (tube C). After 3 minutes’ time, 2.0 mL of a 3 percent hydrogen peroxide solution was added to all three tubes, which were then sealed with a pressure sensor. Pressure data were collected at 30-s intervals for 5 min, at which time the tubes were unsealed and 2.0 mL of a 2N HCl solution was added to all three tubes. The tubes were immediately resealed, and pressure data were again collected for 5 min. The pressure, as measured in kPa, is presented below with tubes A, B, and C in sequence from top to bottom. 

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