Lecture 8 Flashcards
What are photosynthetic challenge
Challenges to the efficiency of photosynthesis
What is important about the evolution of Photosynth?
It had a profound impact on the life of earth
What connects both photo systems
The photosynthetic electron transfer chain connects both photos systems one and two
What is the Z scheme?
One electrons from water goes to photo system two and they enter the photo synthetic electron transfers chain
What does photo system two do
Supplies electrons to the beginning of the electron transfer chain
What does photo system one do?
It energize electrons with second light energy to reduce NADP plus while cytochrome B6F helps transfer electrons
What are the two sources of protons for photosynthetic and electron transfer chain?
Protons get pumped through cytochrome or water produces it
What happens in the cyclic electron transport?
To increase ATP electrons are shunted to different paths by ferredoxin
As ATP increases, what happens to NADPH?
NADPH decreases
What’s a challenge for cyclic electron transport?
If the light density increases electrons have nowhere to go and increases the chance of ROS
What happens when NADP plus is in short supply
Light energy/electron energy converts to O2, which results in ROS
What are the two things body does in order to fight ROS
Antioxidants neutralize ROS AND xanthophylls are orange – yellow pigments that slow ROS formation
What is photorespiration?
The combination of photosynthesis and respiration where RuBisCO adds O2 and not CO2 to RUBP
How much of the sun’s output is not available for photosynthesis
60% of the sun’s output is not available
What did photosynthesis evolve from?
From either horizontal gene transfer or photosystem one/2 duplicating itself and then evolving
