Photosynthesis

Label the parts of the chloroplast

What is the simplified equation for photosynthesis?

The Light Dependent stage of photosynthesis takes place in the thylakoids of chloroplasts

Light energy is captured by Photosystem I and Photosystem II. When light reached PSII electrons are excited and [blank_start]photolysis[blank_end] occurs whereby [blank_start]H2O[blank_end] is broken down into electrons, protons and oxygen, the [blank_start]electrons[blank_end] move into PSII to replace those being lost. The excited electrons provide 1 [blank_start]ATP[blank_end] and eventually move to PSI in [blank_start]non-cyclic photophosphorylation[blank_end]. At PSI more light is captured, exciting more electrons to undergo both; cyclic photophosphorylation and release another [blank_start]ATP[blank_end] molecule, and non-cyclic photophosphorylation. The [blank_start]H+[blank_end] from photolysis and the e- in non-cyclic photophosphorylation move to reduce [blank_start]NADP[blank_end] to NADPH by [blank_start]NADP reductase[blank_end]. [blank_start]ATP[blank_end] and [blank_start]NADPH[blank_end] from the LDS are used in the LIS

In the light independent reaction [blank_start]carbon dioxide[blank_end] is fixed by [blank_start]RuBP (ribulose bisphosphate)[blank_end] using an enzyme called [blank_start]Rubisco[blank_end]. This generates 2 molecules of [blank_start]GP (glycerate-3-phosphate)[blank_end]. ATP and NADPH from the light-dependent reaction are used to convert GP to [blank_start]TP (triose phosphate)[blank_end], this can then be used to regenerate RuBP (5/6) or be converted to [blank_start]carbohydrates[blank_end] (1/6). The light-independent reaction occurs in the [blank_start]stroma[blank_end].

The three rate limiting factors are l[blank_start]ight intensity[blank_end], carbon dioxide [blank_start]concentration[blank_end] and [blank_start]temperature[blank_end]