Photosynthesis- Factors that affect the rate of Photosynthesis Flashcards
How does light intensity affect the rate of photosynthesis?
Light intensity affects the light dependent reactions, the splitting of water and the excitation of electrons in the photosystems. Therefore, low light intensity affects the production of ATP and reduced NADP. Ultimately, the rate of photosynthesis will be low. Higher light intensities Result in a higher rate of photosynthesis
How does carbon dioxide concentration affect the rate of photosynthesis?
CO2 concentration affects the light independent reactions since the quantity of CO2 fixed will determine the amount of triose phosphate that is made and the amount of carbohydrates that are synthesized. Less carbon dioxide is fixed when CO2 concentrations are low. When CO2 concentrations are high more CO2 is fixed, and more carbohydrate is produced.
How does water availability affect the rate of photosynthesis?
If water is in low supply, then less water will be split to supply electrons to PSII. Non-cyclic photophosphorylation will be affected and less ATP and reduced NADP will be produced.
How does the wavelength of light affect the rate of photosynthesis?
The blue and red wavelengths of light are absorbed by photosynthetic pigments to the greatest extent and result in the greatest amount of photosynthetic activity in the plant. The least amount of light is absorbed in the green wavelengths.
How does temperature affect the rate of photosynthesis?
Enzyme controlled stages are sensitive to temperature. At low temps there is less kinetic energy, and the rate of photosynthesis is low; at higher temps there is more kinetic energy so the rate is higher; at very high temps enzymes are denatured and enzyme-controlled reactions are stopped.
How does pH affect the rate of photosynthesis?
pH affects the activity of enzymes, and this will affect the rate.
How does oxygen concentration affect the rate of photosynthesis?
O2 and CO2 both compete for the active site of RUBISCO. Depending on the concentrations of these gases, oxygen successfully enters the active site, and a different reaction takes place. RUBISCO catalyzes a reaction between RUBP and CO2 and also RUBP and O2.
High light intensity and high CO2 concentration (low O2 conc) with low temps, RUBP+CO2 —-> 2GP (fixation of CO2 favored).
High light intensity, high O2 conc (low CO2 conc), high temps,
RUBP + O2——> 1GP+ phosphoglycolate.
Photorespiration reactions result in less GP being produced and the problem of phosphoglycolate which enters mitochondria and is used in respiration to produce CO2.
Photorespiration results in less CO2 being fixed and less carbohydrate being produced in the plant.
It makes photosynthesis 30-40% less efficient.
