Photorespiration Flashcards
How do plants prevent excessive water loss while still having the ability to perform phtosynthesis?
Photorespiration
Also known as the C3 Cycle
Photosynthesis
What is the first product of carbon fixation?
A 3-C compound
Examples of 3-C compounds
Wheat
Soy beans
The entry way of gases, mostly involved in the process of photorespiration wherin it allows the intake of CO2
Stomata
What happens to the stomata during hot days and dry environments
Closes
Temporarily stops the intake of CO2
What happens when the stomata closes and does not allow carbon to pass through?
Levels of O2 inside of the leaves build-up
If the stomata closes, and the levels of CO2 decreases, would the process of photosynthesis be affected?
Yes, due to the lack of supply of CO2, O2 build-up occurs causing increased toxicity
If the stomata closes, and the levels of CO2 decreases, would the process of photosynthesis stop entirely?
It does not stop entirely, yet it would undergo other processes that would require more energy
Does RuBisCO only catalyze the binding of CO2 and RuBP
No, can RuBP mistakenly bind with O2
Why can O2 bind with RuBP?
Due to it being an evolutionary baggage
Why is Photorespiration considered an evolutionary baggage?
The greater pressence of CO2 compared to O2 in the atmosphere before made the process of photosynthesis reliant on it. That does not mean it couldn’t use up O2. Therefore it did not necessarily adapt the ability to repel O2.
Why is using O2 for the cycle harmful?
The products are relatively toxic to plants
Inhibits distinct reactions in the Calvin Cycle
What process decreases photosynthetic output?
Photorespiration
In a general sense, does the pros outweigh the cons in photorespiration?
No, it is relatively toxic
The benefits of Photorespiration
Photoprotection
Help maintain redox balance
Support plant immune defense via peroxisomes
The disadvantages of Photorespiration
Uses more ATP
No sugar is produced
50% of CO2 is lost rather than fixed
Which plants counteract Photoresipiration in its disadvantages
C4 & CAM Plants
Plants that avoid the process of Photorespiration?
Why is C4 Photosynthesis named this way?
Where are C4 Plants common?
Which enzyme catalyzes the fixation of CO2 to form Oxalacetate
What does PEP Carboxylase bind?
What occurs after the fixation of Oxalacetate
How is Malate formed?
An adaptation that allowed C4 Plants to thrive in dry and humid conditions.
In Kranz Anatomy, _______ cells are clustered around bundle-sheath cells which contain more chloroplasts
In C4 plants, the C4 pathway is located in the _______ and connected to the C3 pathway via ______
What happens after Malate enters the bundled-sheat cells?
Why can RuBisCO avoid contact with Oxygen after fixation occurs?
Malate releases CO2 for the Calvin Cycle to use in the C3 pathway, the rest would be converted into _____
PEP is formed with energy from _______, catalyzed via the enzyme _______
How much ATP is expensed after a cycle from C4 Phtosynthesis
The main difference between C4 photosynthesis and CAM Photosynthesis?
During the day, CAM plants….
During the night, CAM plants….
Doe C4 and CAM photosynthesis essentially function the same?
