Photosynthesis Part 2

PHOTOSYNTHESIS PART 2

Lo: Describe the light dependant and light independent stage of photosynthesis​

Open Ended

Identify A-C in the figure.

Open Ended

Carotenoids absorb light in the 500 nm wavelength range. Why does this not show as a high peak in the action spectrum?

Open Ended

Suggest why chloroplast contain more than one different photosynthetic pigments.

​Recall the chemical equation in photosynthesis

6CO₂ + 6H₂0 --> C₆H₁₂O₆ + 6O₂ ​

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​LIGHT- INDEPENDANT REACTION (Stroma)

-carbon fixation

-production of glucose​

​LIGHT- DEPENDANT REACTION

(Thylakoid)

-photolysis

-photoionisation​ / photoactivation of chlorophyll(loss of e)

-​ATP and NADPH production

-chemiosmosis

PHOTOSYNTHESIS

Photosystem II (P680)- absorbs 680nm wavelength of light. Contains oxygen-evolving complex (enzymes in photolysis) ​

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Photosystem I (P700) -absorbs 700 nm wavelength of light​

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​Photosystems

​H₂0 --> 1/2 O₂ + 2e^- + 2H⁺

Photolysis - photo (light) , lysis (split)

​Energy from light is used to split ​water molecules into hydrogen and oxygen...PHOTOLYSIS

H+ is picked up by NADP , e- are passed along the electron carrier proteins

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Predominant in bacteria

Energy is absorbed

​by photosystem 1, exciting chlorophyll in the reaction centre.

​Energy is emitted from chlorophyll a ---photoactivation, accepted by electron carriers, passed along electron carriers.

​​Cyclic photophosphorylation

Predominant in green plants

Energy are absorbed by both photosystems and excited electrons are emitted, absorbed by electron acceptor and passed along electron carriers.

Non-cyclic photophosphorylation

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Multiple Select

What are the products of light dependant reaction? More than one answer

• NADPH

• NADH

• ATP

• glucose

Open Ended

Describe how light energy is used by crop plants during the light dependant reaction [5]

Open Ended

In both mitochondria and chloroplasts, an energetic electron passes along a chain of carriers and the energy released is used to synthesise ATP by chemiosmosis. Suggest why this is referred to as oxidative phosphorylation in mitochondria and photophosphorylation in chloroplast.

Open Ended

What are the differences between cyclic and non cyclic photophosphorylation

Open Ended

Can we say that photosynthesis converts carbon dioxide to oxygen?

Reaction between RuBP and CO2 by the enzyme Rubisco --> 2 GP​

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GP is reduced to 2 x ​TP

5/6 TP are used to regenerate RuBP, 1/6 to make glucose, amino acids, starch ​

GP to make Fatty acids and glycerol​

​Calvin Cycle.

Open Ended

What are the roles of RuBP, NADPH and ATP in the Calvin cycle?

Open Ended

Describe and explain these results.