photosynthesis 3 Flashcards
(20 cards)
What is photorespiration?
A process where Rubisco binds to O2 instead of CO2, leading to the production of phosphoglycolate and a loss of CO2.
What happens when temperature is less than 25°C concerning Rubisco?
Rubisco binds CO2 and produces 2 molecules of 3-PGA.
What happens when temperature is greater than 25°C concerning Rubisco?
Rubisco binds to O2, producing 1 molecule of 3-PGA and 1 molecule of phosphoglycolate.
What is the first product formed when phosphoglycolate is converted?
Glycolate.
Where does glycolate travel after being formed?
To the peroxisome.
What is the final product of glycolate conversion in the mitochondria?
Serine.
What is the significance of photorespiration for C3 plants?
It results in the loss of ¼ to ½ of CO2, massively reducing glucose availability.
What is the first step in the C4 photosynthesis pathway?
CO2 combines with PEP to form oxaloacetate.
What does oxaloacetate convert into in C4 plants?
Malate.
Where does malate diffuse after being formed in C4 plants?
Into the bundle sheath cells.
What is the advantage of PEP in C4 plants?
PEP has a higher affinity for CO2 than O2, reducing photorespiration.
What does CAM stand for?
Crassulacean acid metabolism.
How is the Calvin cycle separated in CAM plants?
The Calvin cycle and C4 cycle are separated in time.
What occurs at night in CAM plants?
Stomata open to release O2 and allow CO2 to enter, which is fixed into malate.
What happens to malate during the day in CAM plants?
Malate is converted into pyruvate, releasing CO2.
What is a key factor that allows Rubisco to favor photosynthesis over photorespiration in CAM plants?
High concentration of CO2.
Fill in the blank: C4 plants produce a 4-carbon molecule called _______.
oxaloacetate.
What are the two main types of plants that utilize alternative carbon fixation methods?
- C4 Plants
- CAM Plants
True or False: Photorespiration occurs in all plants.
False.
What are factors that affect photosynthesis?
Light intensity, carbon dioxide concentration, temperature, and water availability.
