how does light intensity affect the rate of photosynthesis?
An alternative to linear electron flow
It uses a short circuit of the linear electron flow by cycling the excited electrons back to their original starting point in Photosystem I
It only uses Photosystem I with P700 chlorophyll
NO water is split, NO O2 is formed and NO NADPH is generated
ONLY GENERATES ATP - when the concentration of NADPH gets high relative the the concentration of ATP
ATP produced by a process called cyclic photophosphorylation Cyclic Electron Flow Photorespiration 3 Phases Alternate modes of carbon fixation have evolved that minimize photorespiration and optimize the Calvin cycle.
These are the
CAM plants C4 Plants C4 plants live in hot, dry, sunny climates and are adapted to minimize photorespiration
Examples - sugarcane and corn.
They have specially adapted leaves with two kinds of photosynthetic cells
regular mesophyll cells
bundle sheath cells - tightly packed around the leaf vein
In mesophyll cells - CO2 is added to PEP (phosphoenolpyruvate) by the enzyme PEP carboxylase which forms a 4 carbon compound
PEP carboxylase does not bind O2 like rubisco - only CO2
4 carbon compound is exported from mesophyll cell through plasmodesmata to the bundle sheath cell where CO2 is released and available to the Calvin Cycle
CAM Plants Include succulents like cacti and pineapples
They are exposed to hot, sunny, dry weather and are adapted to minimize photorespiration.
They open their stomata at night and close them during the day
During the night CO2 is taken up and incorporated into a variety of organic acids which are stored in vacuoles until daylight
the organic acids release the CO2 during the day when light is available for the light reactions
Chloroplasts have two membranes
Stroma = fluid inside the membranes surrounding the thylakoids
Suspended within the stroma are sacs called thylakoids
Stacked thylakoids are called granum (pl - grana)
Chlorophyll - green pigment that gives the leaves their colour - resides in a thylakoid membranes.
Carotenoids are groups of accessory pigments.
Effect of changing the temperature of reactants
Photosynthesis is the synthesis of organic molecules using the ..
Photosynthesis captures energy for life on Earth. Many chemicals are made to allow life processes to occur in plants. These chemicals can move in and out of cells by the process of diffusion. Osmosis is a specific type of diffusion.
In what parts of the chloroplast does photosynthesis take place?
Overall, it is the reverse reaction of photosynthesis, but chemically, the steps involved are very different.)