Topics since the last exam. Note: only #1- #4 below are covered on this review. Disclaimer: the test may include questions and concepts not presented in this review (although this is a very good place to start.) 1. Starch/sucrose partitioning 2. The ecology of photosynthesis 3. Phloem translocation 4. Respiration 5. Nitrogen assimilation and N-fixing symbiosis 6. Secondary chemistry I, II, & III. 1. Starch - sucrose partitioning • • • What are the major storage and transport carbohydrates in plants? How is starch-sucrose partitioning regulated? Where does starch accumulate? 2. Ecology of photosynthesis •Define water use efficiency •Explain how WUE differs among C3, C4, and CAM •plants and why. • How do sun and shade leaves differ anatomically and physiologically? •How does the chlorophyll/rubisco ratio differ between sun and shade leaves? Explain in terms of the limiting factor for photosynthesis in each case. •Draw light response curves for sun and shade leaves and note key differences. 3. Phloem translocation •List four compounds that are translocated in the phloem. •Define “source” and “sink” as we’ve used the terms to understand the direction of phloem translocation. •How do sieve tube elements differ from tracheary elements? •Draw a figure that illustrates the Münch pressure-flow model of phloem translocation from a source to a sink. •Give representative values for the components of water potential in the phloem and xylem. •Where is energy involved in phloem translocation? •Be able to interpret 14C autoradiograms as we’ve used them for tracing the movement of photoassimilate. •How have aphids been used in understand phloem composition? 4. Plant respiration What are the major products of respiration? What is the major byproduct of respiration that is often measured to understand respiration rate? Write a balanced equation for the complete oxidation of one sucrose molecule. What are the major stages of respiration? Which can proceed in the absence of oxygen? Explain what the alternative oxidase is, how it affects respiratory energy production, and what its function may be in plants. Draw a figure illustrating how the p.m.f. and ATP production are oriented across the mitochondrial membrane system.