For your methods, copy and paste the following paragraph into the Methods of your report, but insert the correct word into the blanks provided.

“Seven spectrophotometer tubes were numbered and solutions A-D were added according to the volumes shown in Table 1. Tube 1 was capped and inverted several times. The was calibrated using Tube 1, which contained chloroplasts and sucrose only, as the blank, to ensure that any changes in ____________ for the other treatments could be attributed to the ___________ of the dye DCPIP. At time zero (mins), absorbance was recorded for all treatments immediately after addition of __________ and mixing of contents. Immediately following the time zero reading, tube 2 was wrapped in foil and tubes 6 and 7 were placed into larger tubes covered in red and green cellophane respectively. Tubes 1-5 were also placed into larger tubes. All tubes were then placed horizontally on ice, under lights. At fifteen minute intervals, readings of absorbance were taken for all treatments, except for the dark tube which was kept wrapped in foil for 60 minutes, after which its absorbance was measured.”

Table 1. Experimental design for the electron transport experiment. | | | | | | TREATMENT | | | | | BLANK 1 | DARK 2 | LIGHT 3 | BOILED 4 | DCMU 5 | RED 6 | GREEN 7 | A | chloroplast suspension (ml) | 1.5 | 1.5 | 1.5 | - | 1.5 | 1.5 | 1.5 | B | buffered sucrose (ml) | 5.5 | 5.3 | 5.3 | 5.3 | 5.2 | 5.3 | 5.3 | C | boiled chloroplast suspension (ml) | - | - | - | 1.5 | - | - | - | D | 0.01 M DCMU (ml) | - | - | - | - | 0.10 | - | - | E | DCPIP (ml) (add this last) | - | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20