Photosynthesis title, definition and equation.

Why does a leaf look green?

Laminaria saccharina uses carotenoids as accessory pigments Laminaria saccharina uses carotenoids as accessory pigments. Light is limited underwater.

Methods of measuring the rate of photosynthesis.

CO2 affects rate of photosynthesis CO2 affects rate of photosynthesis. CO2 is the substrate in carbon fixation (Calvin cycle) – rubisco is the enzyme.

Light intensity affects rate of photosynthesis.

Temperature affects the rate of photosynthesis. Remember enzyme theory. Enzymes used in respiration: rubisco is the main one. ATP synthase can also be denatured.

Chloroplast: colour TEM, parts and functions.

Image source unknown. Question from the IBO. Chloroplast: structure’s relationship with function Image source unknown. Question from the IBO.

Light Dependent Reactions title and brief overview.

Photoactivation of chlorophyll – electrons are excited and return to their original state, releasing oxygen. e-

Photolysis of water produces high-energy electrons, H+ protons and oxygen.

Protons are pumped into stroma using energy from electrons

Photosystem I is activated

Non-cyclic phosphorylation produces ATP.

Reduction of NADP+ by ferredoxin.

Light Independent Reactions title – quick overview.

Carbon fixcation using CO2 and rubisco

Reduction of glycerate 3-phosphate

Carbohydrate formation and re-generation of RuBP

Calvin cycle overview.

Calvin cycle animation links.

Team analogy for the limiting factors theory Team analogy for the limiting factors theory. Time to vote off the weakest link.

Explain the effects of limiting each of the three factors on the process of photosynthesis. It’s not enough to just say “it slows down.”

This graph suggests that CO2 is more important than temperature. Why?

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Iron is limiting – seeding algae with iron stimulates algal blooms. Iron is used in ferroxidase – responsible for reduction of NADP+ in the light dependent reactions. Results with CO2 were short-term. Levels dropped in the immediate area, but the seeding is too expensive to work. Pros: possible reduced CO2 levels, algal blooms provide food for grazers and thus fisheries. Cons: large blooms block light to lower levels, may cause eutrophication; Diatoms block gills of some species; iron seeding may encourage blooms of toxic algae; who owns the ocean?