Mod. 5 Photosynthesis Flashcards
What is the purpose of photosynthesis?
Plants use the energy from light to form bonds to make organic molecules like glucose.
What is photosynthesis?
The process by which energy. in the form of light, is used to build complex organic molecules such as glucose. The light energy is transformed into chemical energy trapped in the bonds of these complex molecules.
What is the basic equation of photosynthesis?
6CO2 + 6H2O –> C6H12O6 + 6O2
Where does photosynthesis take place?
In the thylakoids of the chloroplasts.
How have chloroplasts adapted for maximum effect of their function?
- large network of membranes provides a large surface area to maximise absorption of light.
- Thylakoids are flat, and stacked on top of each other in gramum, maximising the available space.
- packed full of photopigments to absorb a large range of light energy.
Name some photopigments.
Chlorophyll a (primary pigment)
chlorophyll b
xanthophylls
carotenoids
Name some photopigments.
Chlorophyll a (primary pigment)
chlorophyll b
xanthophylls
carotenoids
What colours are most absorbed by plants?
Chlorophyll contains mostly red and blue pigments, and reflects green.
What forms the light harvesting system?
Proteins in the thylakoid membrane such as chlorophyll a and b, as well as other pigments. They absorb light energy from different wavelengths and transfer it to the reaction centre, where chlorophyll a is located.
What happens in the light dependent reactions?
Energy from sunlight is absorbed and used to form ATP and split water by photolysis The H from water is used to reduce NADP.
Light is absorbed by photosystem 2, water is split, and the Hs are split into 2e- and 2H+. The light energy excites the electrons and they are moved along the electron transport chain, and as they reduce each protein, their energy level drops. This allows protons to be pumped into the thylakoid, which diffuse out by chemiosmosis, producing ATP. At the end of the electron transport chain, the 2e-s are re-energised at photosystem 1 by light energy, which then, along with the 2H+, reduce NADP to form NADPH.
The NADP and ATP are then used in the light independent reactions.
What happens in the light independent reactions?
Hydrogen from reduced NADP and CO2 is used to build organic molecules such as glucose. ATP supplies the required energy.
In the stroma, the calvin cycle takes place. CO2 from the air is attached to RuBP (rubisco bisphosphate), forming GP. GP is then reduced by NADPH and ATP, becoming TP. TP has 3Cs and can be used to make biological molecules such as sucrose, glucose, lipids and proteins. The remaining TP is turned back into RuBP to continue the cycle.
What happens in the light independent reactions?
Hydrogen from reduced NADP and CO2 is used to build organic molecules such as glucose. ATP supplies the required energy.
In the stroma, the calvin cycle takes place. CO2 from the light
What are the limiting factors on photosynthesis?
light intensity
CO2 concentration
temperature
What is the result of a change in CO2 concentration on the process of photosynthesis?
CO2 is needed as a source of carbon. Increasing the CO2 concentration increases the rate of carbon fixation in the Calvin cycle, and TP production is increased.
What is the result of a change in CO2 concentration?
CO2 is needed as a source of carbon. Increasing the CO2 concentration increases the rate of carbon fixation in the Calvin cycle, and TP production is increased.
