Bke2 Biochemistry Exercises

Group exercise: Plant biochemistry

Explain the role of plants in the carbon cycle.
Where are the light- and dark-reactions of photosynthesis taking place?
The redox potential is a key concept for the understanding of what drives electron transport in biological membranes. Describe this.
a) What are the main components of light-driven photosynthesis? b) The Z scheme is often used to describe how the main components of the light driven photosynthetic electron transfer work together to create redox energy. Draw this scheme as simple as possible, i.e. organise the main components relative to each other and with respect to the redox potential.
What is the major difference between antenna pigments (chlorophylls) and the reaction centre?
How is light energy used to produce ATP? What is the role of the membrane? Differentiate between cyclic and noncyclic photophosporylation in green plants and describe how photosystems I and II are involved in each process.
What is the main purpose of the dark reaction?
Triose-phosphate is an important intermediate in the photosynthetic dark reaction. a) What are the steps leading to triose-phosphate? b) What is the fate of triose-phosphate (inside the Calvin cycle, as well as outside)?
What is the name of the CO₂-fixing enzyme? What other reaction(s) are catalysed by this enzyme? What consequences does this have for net carbon fixation?
Compare and contrast CO₂ fixation in C3 and C4 plants.

Reading material: Horton, Chapter 16 in 2nd Ed; Chapter 15 in 3rd Ed.

Lectures:
Plant biochemistry
Photosynthesis dark reactions
Photosynthesis light reactions

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