Algae are a diverse group of photosynthetic eukaryotes in the kingdom Protoctista. Rhodomonas salina and Skeletonema costatum are two species of alga that live in seawater. Fig. 1.1 shows a scanning electron micrograph of $$\(R\)$$. salina, which is a unicellular organism. $$\(R\)$$. salina is red in colour. Fig. 1.1 Fig. 1.2 shows a scanning electron micrograph of $$\(S\)$$. costatum, which is also a unicellular organism. The individual cells can group together in a chain. S. costatum is yellow-brown in colour. Fig. 1.2 A student prepared extracts of the photosynthetic pigments from R. salina and S. costatum. The student carried out chromatography to identify and compare the pigments in the two species. The chromatograms are shown in Fig. 1.3. Fig. 1.3 (i) Use Fig. 1.3 to calculate the $$\(\mathrm{R}_{\mathrm{f}}\)$$ value of alloxanthin from $$\(R\)$$. salina. $$\(R_{f}\)$$ of alloxanthin = ..................................................... (ii) Table 1.1 shows the $$\(R_{f}\)$$ values of some photosynthetic pigments. Table 1.1 $$\(R\)$$. salina lacks two photosynthetic pigments that are present in S. costatum. Use Fig. 1.3 and Table 1.1 to identify the two photosynthetic pigments that are present in only S. costatum. ....................................................................................................................................... . .................................................................................................................................

Answer:

Knowledge points:

Solution: