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Photosynthesis is a process that releases energy by capturing sunlight. As a byproduct, it
releases oxygen, which most organisms use to respire.

Light energy is used to synthesise organic molecules such as glucose. The reactions are a
series of enzymecontrolled reactions and anything that affects the rate of enzyme…

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The LightDependent Reactions
The LDRs occur in the thylakoid membranes, which contain many tightly packed
chlorophyll molecules and in this light is captured by the chlorophyll, which is used to:
Provide energy to produce one molecule of ATP
Split water into two protons, two electrons and half an oxygen molecule…

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1. Light strikes chlorophyll and a pair of electrons become excited (gain energy) and
become so energetic they leave chlorophyll and are picked up by an electron
2. Now the electrons are passed down an electron transport chain across the thylakoid
membranes generating a molecule of ATP from the…

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N.B. Whilst the diagram above does not depict the different photosystems and the true
nature of photosynthesis, it is all that is required by the AQA specification.

LightIndependent Reactions
The lightindependent reactions do not require light, however they do need the products of
the lightdependent reactions, the ATP and…

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CO2 combines with a 5carbon molecule known as ribulose bisphosphate (RUBP)
to form two molecules of gylcerate3phosphate (GP).
The ATP and reduced NADP produced in the lightdependent reaction reduce GP
to triose phosphate (TP). The ATP provides the energy and the reduced NADP
provides the hydrogen.
NADP is reformed and…

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The lightindependent reaction occurs in the stroma, which contains the necessary enzymes
for the reactions to occur.

The chloroplast also contains DNA and ribosomes that allow it to carry out protein

Remember, AQA like to ask where certain reactions occur, so make sure you know
which occurs in the…

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As temperature increases, the rate of
photosynthesis increases as it is the
limiting factor and the enzymes that
control photosynthesis will have more
kinetic energy and hence more
enzymesubstrate complexes form.

At the peak this is the optimum

Temperatures beyond the optimum
temperature cause the enzymes to

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Commercial Glasshouses
The limiting factors of photosynthesis can be controlled to:
Achieve higher yields.
Grow crops out of season.
Grow crops that wouldn't usually be able to survive in a certain climate.

The faster the rates of photosynthesis, the more carbohydrates the plants make and hence
the more energy is…

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There are however costs involved when controlling the environment and hence it is
only worth doing if the increase in yield outweighs the costs.





Thanks, these notes are really good :)

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