The process of C3 photosynthesis Flashcards
The purpose of photosynthesis is to
produce usable chemical energy in the form of glucose from light energy.
the simplified equation of photosynthesis
6 CO2 + 6 H2O –> C6 H12 O2 + 6 O2
The inputs of the light-dependent stage of photosynthesis are: (4)
NADP+, H2O, ADP + Pi, light energy
The outputs of the light-dependent stage of photosynthesis are: (3)
O2, NADPH, and ATP
The inputs of the light-independent stage are: (3)
CO2, NADPH, ATP
What are the outputs of the light-independent stage? (3)
Glucose (or G3P), ADP + Pi, and NADP⁺.
Where does the light-dependent and light-independent stage occur?
light-dependent stage- Thylakoid Membrane and light-independent- Stoma
What is the main purpose of the light-dependent stage?
To convert light energy into chemical energy (ATP and NADPH)
Do the light-dependent and light-independent stages happen at the same time?
Yes — they can happen at the same time, but only when light is available.
Photolysis
The splitting of water using light energy to produce oxygen, electrons, and hydrogen ions.
What are the products of photolysis?
O₂, electrons (e⁻), and H⁺ ions.
What role does chlorophyll play?
It absorbs light energy and excites electrons.
What is the purpose of Light-independent reactions?
To produce glucose (C₆H₁₂O₆) from carbon dioxide.
Other Names for the Light-independent reaction :
Calvin Cycle
Dark reactions (Note: It doesn’t mean they only happen in the dark — just that they don’t directly require light)
Carbon fixation cycle
C₃ cycle (because the first stable product is a 3-carbon compound – 3-PGA)
What happens during carbon fixation?
CO₂ is fixed into an organic molecule using the enzyme RuBisCO.
What provides energy for the Calvin Cycle?
ATP and NADPH from the light-dependent stage.
Is light directly required for the Calvin Cycle?
No, but it depends on the products of the light-dependent reactions.
What is the correct order of steps in photosynthesis?
- Light energy is absorbed by chlorophyll
- Water molecules are split into H⁺, O₂, and electrons
- H⁺ binds to NADP⁺ to form NADPH
- Oxygen is released or used in respiration
- Carbon dioxide enters the Calvin cycle
- Glucose is produced
Plants are considered ‘bottom of the food chain’ as
they produce their own food which allows for animals to eat plants and therefore animals to eat other animals.
What do Phytoplankton do?
turn sunlight into glucose.
Photosynthesis can’t occur in the deep ocean because
water cannot be split and electrons cannot be excited in the light-dependent stage because light is not available in this habitat to provide the necessary energy for the reactions.
Chemosynthesis is similar to photosynthesis as both processes
allow for the conversion of an otherwise unusable form of energy into a usable food source.
primary function of a chloroplast?
light energy is converted into chemical energy
A molecule that plays a role in many biochemical reactions is
ATP
