Topic 8.3

Essential idea: Light energy is converted into chemical energy


Where does photosynthesis take place in a leaf?

Photosynthesis consists of light dependent and light independent reactions. Light dependent reactions take place in the chloroplasts of the leaf which is shown below. Placing the mouse pointer on the diagram will reveal a labelled diagram of the chloroplast. Also the location of the thylakoids within the chloroplast and the position of PSII which contains chlorophyll P680), PSI (which contains chlorophyll P700) and ATP Synthase within the thylakoid membrane.

Placing your mouse pointer on the electron micrograph below will reveal a labelled diagram of the chloroplast.

Chloroplast Structure

8.3.U1 Light-dependent reactions take place in the intermembrane space of the thylakoid

Light dependent reactions in the thylakoid

8.3.U2 Light-independent reactions take place in the stroma

Light independent reactions in the stroma

8.3.U3 Reduced and NADP and ATP are produced in the light-dependent reactions

Production of ATP and NADPH

8.3.U4 Absorption of light by photosystems generates excited electrons

Diagram of absorption of light in chloroplasts

8.3.U5 Photolysis of water generates electrons for use in the light-dependent reactions

Splitting of water in the chloroplast

8.3.U6 Transfer of excite electrons occurs between carriers and thylakoid membranes

Transfer of electrons in the thylakoid membrane

8.3.U7 Excited electrons from Photosystem II are used to contribute to generate a proton gradient

Establishing a proton gradient in the thylakoid

8.3.U8 ATP synthase in thylakoid generates ATP using the proton gradient

ATP production in the thylakoid

8.3.U9 Excited electrons from Photosystem I are used to reduce an ADP

Production of NADPH in thylakoid

8.3.U10 In the light-independent reactions a carboxylase catalyzes the carboxylation of ribose bisphosphonate

Fixation of carbon dioxide

8.3.U11 Glycerate 3-phosphate is reduced to triose phosphate using reduced NADP and ATP

Reduction of glycerate-3-phosphate

8.3.U12 Triose phosphate is used to regenerate RUBP and produce carbohydrates

Triose used for RUBP and carbohydrate production

8.3.U13 Ribulose bisphosphate is formed using ATP

Diagram of regeneration of RUBP

8.3.U14 The structure of the chloroplast adapted to its function in photosynthesis

Chloroplast structure and function


8.3.A1 Calvin's experiment to elucidate the carboxylation of RUBP

Place your mouse pointer on the experiment set-up to view results

Chloroplast Structure

Place your mouse pointer on the question to view the conclusion

Conclusion of Benson and Calvin experiments

Place your mouse pointer on the question to view the answer

Next question asked by Calvin and colleagues


8.3.S1 Annotation of a diagram to indicate the adaptations of a chloroplasts to its function

Place your mouse pointer on the diagram to view labelled structures and functions.

Diagram of unannotated chloroplast
Back to top of page

Valid XHTML 1.0 Strict Valid CSS!