B explain how gas exchange affects transpiration c

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(b) Explain how gas exchange affects transpiration. (c) Describe TWO adaptations that affect the rate of transpiration in desert plants. 2006 In many ways, all organisms in a food web can be said to be solar-powered. The producer level of the food web is responsible for the transformation of solar energy into a form that can be used by other living organisms. (a) Discuss the role of green plants in transforming the Sun’s energy into a form that can be used by heterotrophs. (b) Discuss the flow of energy from producers through top carnivores in a food web in terms of the laws of thermodynamics. 2005:
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AP BIOLOGY 4 A controlled experiment was conducted to analyze the effects of darkness and boiling on the photosynthetic rate of incubated chloroplast suspensions. The dye reduction technique was used. Each chloroplast suspension was mixed with DPIP, an electron acceptor that changes from blue to clear when it is reduced. Each sample was placed individually in a spectrophotometer and the percent transmittance was recorded. The tree samples used were prepared as follows. *Sample 1 – chloroplast suspension + DPIP *Sample 2 – chloroplast suspension surrounded by foil wrap to provide a dark environment + DPIP *Sample 3 – chloroplast suspension that has been boiled + DPIP Percent Transmittance in Three Samples Time (min) Light, Unboiled % Transmittance Sample 1 Dark, Unboiled % Transmittance Sample 2 Light, Boiled % Transmittance Sample 3 0 28.8 29.2 28.8 5 48.7 30.1 29.2 10 57.8 31.2 29.4 15 62.5 32.4 28.7 20 66.7 31.8 28.5 (a) On the axis provided, construct and label a graph showing the results for the three samples. (b) Identify and explain the control or controls for this experiment. (c) The differences in the curves of the graphed data indicate that there were differences in the number of electrons produced in the three samples during the experiment. Discuss how electrons are generated in photosynthesis and why the three samples gave different transmittance results. 2006 In many ways, all organisms in a food web can be said to be solar-powered. The producer level of the food web is responsible for the transformation of the solar energy into a form that can be used by other living organisms. (a) Discuss the role of green plants in transforming the Sun’s energy into a form that can ultimately be used by heterotrophs. (b) Discuss the flow of energy from producers to top carnivores in a food web in terms of the laws of thermodynamics. 2009: Water is essential to all living things. (a) Discuss THREE properties of water (b) Explain each of the following in terms of the properties of water. You are not limited to the three properties discussed in part (a): The role of water as a medium for the metabolic processes of cells The ability of water to moderate temperature within living organism and in organisms’ environments The movement of water from the roots to the leaves of plants 2010 Biological molecules can be separated by using chromatographic techniques. The diagram above shows the separation of several spinach leaf pigments by paper chromatography. Using the diagram above: (a) Explain how paper chromatography can be used to separate pigments based on their chemical and physical properties. (b) Discuss the role of pigments both in capturing light energy and in converting it to the chemical energy of ATP and NADPH. (c) Use the ruler above to determine the R f value of xanthophylls. Show your calculations.
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b Explain how gas exchange affects transpiration c Describe...

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