Photosynthesis Flashcards
What two reactions are forms of photosynthesis
Light dependent
Light independent
Name two types of photosynthetic pigments
Chlorophylls
Carotenoids
Why is it beneficial to a plant to have more types of photosynthetic pigments
Different pigments absorb different wavelengths of light and so the more different types of pigments the greater range of the wavelengths they are able to absorb.
What is chlorophyll A known as
The primary pigment
What are all types of pigments other than chlorophyll A known as
Accessory pigments
What is a photosystem
a collection of accessory pigments which pick up light at various wavelengths and funnel this energy to the reaction centre, a chlorophyll A molecule
Which mineral ion is a key component of chlorophyll
Magnesium
What is photolysis
The splitting of water molecules into 2H+ and 1/2O2
What is photophosphorylation
Adding phosphate using light
What is the role of NADP in photosynthesis
Acts as a hydrogen carrier and is reduced to become red.NADP
Where do the electrons come from which replace those lost from photosystem 2 during non-cyclic phosphorylation
The photolysis of water
Where do the electrons come from which replace those lost in photosystem during non-cyclic phosphorylation
From photosystem 2
Where do the electrons and hydrogens come from which enable NADP to be reduced
The electrons come from photosystem 1 and the hydrogens come from the photolysis of water
What is done with the oxygen produced from non-cyclic phosphorylation
It is released as a waste product
What is cyclic phosphorylation
This only involves photosystem 1. The electrons released return back to the photosystem they were promoted from
What drives the light independent reaction
Enzyme called RuBISCO
How is CO2 used in the light independent reaction
It is fixed to RuBP
List the molecules formed in the Calvin Cycle
RuBP Unstable Intermediate Glycerate 3-phosphate Triose Phosphate RuBP etc...
Where is ATP used in the Calvin Cycle
Between Glycerate 3-phosphate and Triose phosphate, and between Triose Phosphate and RuBP
Where is glucose produced in the Calvin Cycle
The synthesis of Triose Phosphate
What happens to the ADP + Pi and NADP after the Calvin Cycle
It returns to the light dependent reaction to be used there
What is an absorption spectrum
how much light a particular pigment absorbs at each wavelength
What is an action spectrum
The rate of photosynthesis at different wavelengths of light
How did Englemann’s Experiment work
He used respiring bacteria that had the ability to move and noted that they moved to areas of oxygen density to identify that photosynthesis takes place in the chloroplasts
Name factors that limit photosynthesis
Light intensity Carbon Dioxide Water Minerals Temperature Chlorophyll
What is the light compensation point
The light intensity at which a plant has no net gas exchange as the volume gases used and produced
What is the light saturation point
Any increase in the light intensity striking the leaf does not cause an increase in the rate of photosynthesis
What is the light saturation point indicated by
The level of O2 being evolved levels off
Name some adaptations that sun plants have
Smaller surface area Leaf blade is thicker Palisade layer is thicker Fewer Chloroplasts Less accessory pigments
Name some adaptations that shade plants have
Bigger surface area Thinner leaf blade Thinner Palisade layer More chloroplasts More accessory pigments
How is nitrogen deficiency shown in plants
Plants with low levels of nitrates have older leaves that turn yellow and die. Their growth is also stunted.
How is magnesium deficiency shown in plants
A lack of magnesium causes both old and new leaves to turn to yellow and growth to slow down
