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1. Soya beans and beef produced on the land are good sources of protein. The table below shows the nutritional content of products made from soya and beef.
(i) using the data from the table, state and explain two reasons why soya sausages may be healthier than corned beef as a major item in the diet. 1 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 2 -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- (4) 2. A typical dicot leaf contains a number of different type of cells, including: guard cells, palisade mesophyll, spongy mesophyll and upper epidermal cells Using the type of cells listed above, complete the table by a) writing the types of cells in the order that sunlight passes through them, b) stating the proportion of chloroplasts in each of the types of cells. Use the terms none, some and many.
(3) Stomatal pores are surrounded by pairs of guard cells. When the stomata are closed the rate of photosynthesis is affected, due to a limiting factor. c i) Write a balanced equation, using chemical symbols, for the process of photosynthesis. ------------------------------------------------------------------------------------------------------(2) ii) Define the term limiting factor ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(2) iii) State the factor that limits photosynthesis when the stomata are closed. ------------------------------------------------------------------------------------------------------(1) d) vascular bundles, containing xylem and phloem tissue, are situated in the leaf. i) describe the structure of xylem tissue. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(3) ii) State the functions of xylem and phloem. Function of xylem --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Function of phloem -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(4) e) Some plants close their stomata during the hottest part of the day, despite the effect on photosynthesis. Suggest what benefit this might be to the plants. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------(1)
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