photosynthesis C4 and CAM Flashcards
What is the most important enzyme for an light independent stage
Rubisco
Is Rubisco a teritiary or quatenary protien
Quataneray Protien
What does the Rubsico ENzyme do? (role)
The Rubsico undergoes Carbon Fixation converts inorganic carbon dioxide gas to an organic compound called- **3-PGA*
What does carbon fixation mean
The turning of inorganic carbon in organic compounds like glucose
What is the slight problem with Rubsico in light independent reactions and why would it be bad.
Rubsico also can bind to oygen as an substrate which causes photorespiration leading to less glucose.
What is photorespiration
and how it is bad
When oxygen binds to Rubisco and prevents the production of glucose.
1.A waste of energy
2.And essentially disrupts photosyntheisis.
What are the two reasons for more photorespiration in hot and dry conditions
Just list the two dot points
- Substrate Concentration
- Tempreature
Explain substrate concentration affect on photorespiration IN HOT AND dry enviorment
When there is high water loss, the stomata closes and stays closed, trapping all the Oxygen made from light dependant reactions and preventing carbon dioxide from entering. This increases the oygen concentration near rubisco, increasing the chance of binding with the rubsico and oxygen.
Explain temperature affect on photorespiration IN HOT AND dry enviorment
A higher tempreature causes a higher affinity for rubsico to bind with Oxygen
What type of plants are majority of plants, C3 C4 OR CAM
c3 plants
What cells undergo the light independent stage in C3 plants
JUST the mesophyll cell
What adaptations do C3 plants have to prevent photorespiration
NONE they posses no adaptations to prevent photorespiration
What is different about the light independent stage in c4 plants compared to C3 plants
Inital Carbon fixation happens in the mesophyll cell, wheras the rest of the calvin cycle occys in the bundle sheath cell.
How does seperating the light independent stage in C4 plants prevent photorespiration?
As there is a constant pump of C02 from the mesophyll cell to the bundle sheath cell, the calvin cycle will continue with a higher concentration than O2 for binding with RUBISCO. This is because Oxygen produced in the light dependent stage is produced and kept in the mesophyl cell, seperated from the calvin cycle stage.
What is an example of an C4 plant?
Corn or weed
What is one bad thing about C4 plants compared to c3 platns
C4 plants requires more energy for photosynthesis
What does CAM plants have as an adaptation to minimise photorespiration
Seperates light- independent stage over time, Night and Daytime.
What happens at night time for CAM plants
CAM plants open their stomata at night as it cooler and intakes carbon dioxide and converts it into malate that is stored inside the vacuoles in mesophyll cells.
What happens at daytime for CAM plants
At daytime, the stomata closes to prevent water loss as it is warmer.
It then releases malate to be broken down back to carbon dioxide and be used in the Calvin Cycle
How does CAM plants even maximise photosynthesis and minimises photorespiration
The controlled release of malate ensures there is a high concentration of C02 near rubisco.
Does CAM plants take more energy than C3
Yes
