Photosynthesis (Unit 2) Flashcards
What are the two main stages of photosynthesis?
The two main stages of photosynthesis are the light-dependent reactions (‘photo’) and the Calvin cycle (‘synthesis’).
Where do light-dependent reactions occur and what do they require?
Light-dependent reactions occur in the thylakoid membranes of chloroplasts and require chlorophyll and pigments.
What is the main purpose of light-dependent reactions?
The main purpose of light-dependent reactions is to capture light energy to make ATP and reduce NADP+ to NADPH.
Where does the Calvin cycle occur and what does it use?
The Calvin cycle occurs in the stroma of chloroplasts and uses the free energy in ATP and the reducing power of NADPH to create organic compounds.
What is the overall equation for photosynthesis?
The overall equation for photosynthesis is: 6CO₂ + 6H₂O + light energy = C₆H₁₂O₆ (glucose) + 6O₂.
What is the structure of a chloroplast?
A chloroplast has an outer and inner membrane, thylakoids that form grana (stacks), lamellae (unstacked thylakoids), and stroma (protein-rich semi-liquid material).
How does the structure of the thylakoid system within chloroplasts aid photosynthesis?
The structure of the thylakoid system increases surface area, amplifying photosynthesis by containing light-gathering pigment molecules and the electron transport chain (ETC).
What is chlorophyll and what are its two forms?
Chlorophyll is a pigment that absorbs light energy, with two forms: chlorophyll a (blue/green) and chlorophyll b (yellow/green).
How do chlorophyll a and chlorophyll b differ in function?
Chlorophyll a becomes oxidized and donates electrons to the primary electron acceptor, while chlorophyll b transfers electrons to chlorophyll a.
Describe the structure of chlorophyll molecules.
Chlorophyll molecules have an H-C tail and a ring with alternating single and double bonds, containing delocalized electrons that can absorb light energy
What are pigments and photosystems?
Pigments are organized into large photosystems, each containing an antenna complex (transfers energy to the reaction center) and a reaction center (where chlorophyll a gets its electrons excited and donates them to the primary electron acceptor).
What does the antenna complex in a photosystem do?
The antenna complex in a photosystem is a web of chlorophyll and other pigments that transfer energy to the reaction center by capturing light photons.
What role does the reaction center in a photosystem play?
In the reaction center, chlorophyll a gets its electrons excited and donates them to the primary electron acceptor.
