Yes - photosynthesis in plants is carried out mainly by three pigments: chlorophyll a (teal), chlorophyll b (green), and beta carotene (yellow). Any other colored pigment reflects light that might otherwise be used by the photosynthetic pigments (keep in mind, this is blue or red light - chlorophylls reflect away the teal through yellow!). If there red pigment on the underside of a leaf, then that will reflect red light back through the leaf, which increases efficiency; otherwise, it will decrease it.

That's an interesting question. Chlorophyll-a is the main photosynthetic pigment. Others are chlorophyll-b, beta-carotene, and other carotenoid pigments, in land plants. They absorb light in different parts of the visible spectrum.

So the efficiency of photosynthesis would depend on what all photosynthetic pigments a plant had - the short answer to your question is 'Yes.'

You might like to look at this website to learn more, or search for yourself on google.