Biology 0610 · IGCSE · Photosynthesis

Photosynthesis — practice question

A student carried out an investigation into how the concentration of carbon dioxide affects the rate of photosynthesis in an aquatic plant. Sodium hydrogencarbonate was used to create different carbon dioxide concentrations in the water. The students counted the number of gas bubbles given off in one minute at different carbon dioxide concentrations. Fig. 2.1 shows the apparatus that was used. Table 2.1 presents the results.
(a)[5]

Complete the sentences to describe and explain the results shown in Table 2.1. As the carbon dioxide concentration increases, the number of gas bubbles released in one minute ............ and then levels off. This happens because carbon dioxide is a ............ material needed for photosynthesis. The number of gas bubbles released stays unchanged between the carbon dioxide concentrations of ............ and ............ arbitrary units. Photosynthesis produces ............ gas which is released as bubbles. The distance between the lamp and the aquatic plant is kept constant during the investigation so that the light ............ stays the same.

(b)[4]

Explain the role of the green pigment in plant nutrition.

(c)[1]

State the process in plants that releases carbon dioxide.

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