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Flashcards in Photosynthesis Deck (11):

Compensation point

The light intensity level in which the rate of photosynthesis exactly matches the rate of respiration


Photosynthetic pigments

Coloured substances that absorb the light energy needed for photosynthesis.

They are light harvesting


Example of photosynthetic pigment

Wavelengths of light absorbed in two photosytems

Chlorophyll A

PS1 700nm
PS2 680nm



It contains enzymes, sugars and organic acids


What does reductase do

Accepts protons from the atp synthase pump and joins them with NADP to produce reduced NADP


What does ferredoxin do

Accepts e- from PS1 and combines them with NADP in the stroma to make reduced NADP


What uses cyclic photophosphorylation

Guard cells

They produce ATP which brings potassium ions into the cells, lowering the water potential so that water follows by osmosis. Swell and opens stomata.


How many turns of the calvin cycle is needed for 1 hexose sugar

What can TP be made into


Carbohydrates, lipids and amino acids

Carbohydrates= two triose phosphate molecules form a hexose sugar

Lipids= glycerol and fatty acids. Glycerol synthesised from triose phosphate, where as fatty acids from glycerine 3 phosphate

amino acids= glycerine 3 phosphate


What colour sunlight does chlorophyll A and B absorb

Red and blue


What is the saturation point

Where a factor is no longer a limiting factor

For example, increasing light past this point makes no difference as something else has to be a limiting factor


What is a limiting factor

Variable that can slow down the rate of reaction