Photosynthesis Flashcards
two different stages?
Light dependent and light independent/Calvin’s cycle
Place that dependent reaction takes place?
Thylakoid membrane
Place independent reaction takes place?
Stroma
What is photlysis?
Splitting of water with light
What is a heterophobic organism?
Obtain complex organisms by eating other organisms
What is a autotrophic?
An organism that photosynthesize
Equation for photosynthesis?
6CO2 + 6H2O –> C6H12O6 + 6O2
What is a thylakoid?
Flattened sacs formed by the membrane where photosynthesis takes place
A stack of thylakoids is called a?
Grana (singular = granum)
Colors that chlorophyll absorbs?
Red and blue, reflects green making the leaves that color
Chlorophyll A?
The primary pigment, at the bottom of the photosystem
Photosystem I?
Happens second has a wavelength of 700nm
Photosystem II?
Happens first, has a wavelength of 680nm
Chlorophyll B?
Accessory pigments, get excited by the light and vibrate creating kinetic energy
Adaptations of the waxy cuticle?
Transparent for light to pass through, prevents water loss to the plant
Palisade adaptations?
Close together = shorter diffusion pathways, contains loads of chloroplasts to absorb more light, close to top of leaf, columnar to fit more near the top
Explain how the light dependent stage happens?
PSII occurs with sunlight, fires electrons slowly losing energy to get to an electron transport chain, photolysis of water happens to replenish the lost electrons, and producing hydrogen for NADP and oxygen as a byproduct. The electron transport chain produces ATP and the electrons go to PSI here’s where the electrons can either go cyclic or non-cyclic, back to the ETC or provide energy to NADP to make NADPH for the independent stage
Products of the light dependent stage?
ATP, NADPH and O2
First stage of the Calvin cycle?
RuBP combines with CO2 and is catalyzed by Rubisco to make a 6C compound
2nd stage of Calvin’s cycle?
The 6C compound breaks down and makes GP and in the process makes carbon dioxide fixated, GP is converted into TP using NADPH and ATP energy
What happens with TP in the Calvin’s cycle?
TP can be converted into hexose sugars such as glucose or glycerol, fatty acids and lipids. Or it will get recycled into RuBP to restart the cycle again
Three overall steps of the Calvin’s cycle?
Fixation of CO2, Reduction of GP to TP and Regeneration of RuBP from recycled TP
What is photorespiration?
When oxygen inhibits the enzyme Rubisco, reducing production of GP. Phosphoglycerate is formed, needs to be removed as toxic to the plant.
Percentage of products lost during photorespiration?
25%
The affinity of Rubisco?
High affinity for carbon dioxide compared to oxygen
Why is the most critical enzyme in photosynthesis inhibited by a common molecule such as oxygen?
When plants evolved to respire in the beginning of time there was no oxygen present in the atmosphere, only CO2 and nitrogen. As time passed more oxygen came into the atmosphere, plants haven’t evolved to counter the increase in oxygen
3 types of limiting factors?
Temperature, light intensity and CO2 concentration
What happens as light intensity increases?
ATP and NADP are produced at a quicker rate so photosynthesis all together is performed quicker.
What happens if light intensity is decreased?
Light dependent reaction will slow down, less ATP and NADP. Increase in GP concentration as less is being converted into TP as less ATP and NADP. As there is less TP that means less being recycled into RuBP
What happens if temperature is increased?
The enzyme such as NADP and Rubisco are affected. Temp increase = more kinetic energy and successful collisions = more enzyme activity. Enzymes eventually denature which will slow down the process of photosynthesis.
