What is a photo system
A light capturing complex
Located in thylakoid membrane IN A CHLOROPLAST
Contains different pigments- each pigment absorbs a different wavelength of light
What is the antennae complex in photosystems
Contains chlorophyll a, chlorophyll b and the carotenoids (xanthophylll and beta carotene)
Light energy is absorbed by antennae complex’s and passed to reaction centre
What is the reaction centre in a photosystem
Contains 2 molecules of chlorophyll a
Electrons in these molecules are excited by the light energy passed down through antennae complex
What is a chloroplast
A transducer
Converts light energy into chemical energy
What is chromatography used for in photosynthesis
To observe and identify different pigments involved in photosynthesis
Rf value equation
Distance travelled by pigment divided by distance travelled by solvent front
What is the explanation for the action spectrum and absorption spectrum graphs following the same trend
Gives evidence that the light absorbing pigments are responsible for photosynthesis
What does an absorbance spectra show
Absorbances of the different wavelengths of light for each pigment
What does the action spectra show
Rate of photosynthesis at different wavelengths of light
Function of nitrogen as nitrates or as ammonium and what would a deficiency cause
Synthesis of proteins, nucleic acids and chlorophylls
Deficiency results in reduced growth of all organs and yellowing of leaves (chlorosis)
Function of magnesium and what would Mg deficiency cause
Chlorophyll production
Deficiency results in chlorosis
What would happen to pH if rate of photosynthesis is high
- pH will increase as more CO2 is removed for photosynthesis
Why is rate of photosynthesis low between 500 and 600nm wavelength
- less absorption of these wavelengths by plant
- light is required for light dependent reaction
- 500-600 is green light which is reflected by plants
what wavelengths have the highest rate of light absorption
short and long
what wavelengths have the lowest rate of light absorption
500nm
green
What is the final electron acceptor
Oxygen
Predict the effect of crops with an enhanced uptake of carbon dioxide might have on the carbon cycle and the impact this might have on endangered species
- more CO2 absorbed by plant
- will improve prospects for endangered species
- because less CO2 results in less global warming leading to less habitat destruction
When investigating the effect of light intensity on rate of photosynthesis why might the expected volume of gas collected be higher than the actual volume of gas collected at the highest light intensity
- light is not limiting as it is at the highest intensity
- so temperature/ CO2 level is limiting
Given this equation
6CO2 + 6H2O → C6H12O6 + 6O2
Why might it be correct that all of the oxygen released came from carbon dioxide
12 atoms of o2 reacted
12 atoms of o2 produced
How do describe an absorption spectra
Peaks at ……
Minimal/ less absorbable between ….. and ….
