2.2.4 Maximising Photosynthesis Flashcards
What is C4 photosynthesis?
A type of photosynthesis where carbon fixation occurs in two different cells separated by space.
What is CAM photosynthesis?
A type of photosynthesis where carbon fixation occurs at different times, allowing stomata to remain closed during the day.
What is photorespiration?
A process that occurs when Rubisco uses oxygen instead of carbon dioxide, reducing the efficiency of photosynthesis.
What enzyme catalyzes carbon fixation in plants?
Rubisco
What happens when Rubisco binds with O2?
It leads to photorespiration.
What happens when Rubisco binds with CO2?
It leads to carbon fixation.
How does photorespiration affect the Calvin Cycle?
It reduces the efficiency by about 25%.
What are the two main types of cells involved in C4 photosynthesis?
Mesophyll cells and bundle sheath cells.
What is the role of PEP carboxylase in C4 photosynthesis?
It fixes CO2 at the start without competition from O2.
What are some advantages of C4 photosynthesis?
- High concentration of CO2 in bundle sheath cells
- Decreased rates of photorespiration
- Advantageous in hot environments
What are some disadvantages of C4 photosynthesis?
- Requires ATP to convert pyruvate to PEP
- Uses more energy than C3 photosynthesis
What are some advantages of CAM photosynthesis?
- Stomata do not have to open during the day
- High concentration of malate in vacuoles
- Minimizes photorespiration
What is a disadvantage of CAM photosynthesis?
ATP is required to regenerate PEP carboxylase.
Which type of photosynthesis minimizes photorespiration?
C4 and CAM
When are stomata open in C3 photosynthesis?
During the day.
When are stomata open in CAM photosynthesis?
At night.
What types of environments are C4 plants best adapted to?
Hot and sunny environments.
What types of environments are CAM plants best adapted to?
Very hot, dry habitats.
Give examples of C3 plants.
- Wheat
- Rice
- All trees
Give examples of C4 plants.
- Corn
- Sugarcane
- Switchgrass
Give examples of CAM plants.
- Cacti
- Pineapples
- Orchids
What is the main difference in separation between C4 and CAM photosynthesis?
C4 separates by space, while CAM separates by time.
True or False: C3 photosynthesis uses extra energy compared to C4 and CAM.
False
Fill in the blank: C4 photosynthesis helps to minimize _______.
photorespiration
