Photosynthesis (L9) Flashcards
This is the synthesis of energy/food using light in plants.
Photosynthesis
Where does photosynthesis occur in plants?
Chloroplasts
- more specifically, light reactions take place in the thylakoid membrane
- carbon fixation occurs in the stroma
These reactions use chlorophyll (pigment) to capture light energy and convert it to chemical energy using protein complexes embedded in the thylakoid membrane.
Light reactions
Remember: these take place in the stroma (which is far more exposed than the thylakoids and thylakoid membrane)
What does PETC stand for? What is its function?
Photosynthetic Electron Transport Chain.
A pathway that electrons travel through to produce a concentration gradient.
Like as the electrons go through, protons are pumped into the opposite side of the membrane to establish a concentration gradient.
What are the sequence of events in the PETC?
Where does it occur?
Remember: photosystems are protein complexes that produce high energy electrons (green picture LTH - PETC concept)
- in the thylakoid membrane
Photosystem II — Cytochrome Complex — Photosystem I — ATP synthase
(Poodle Crouches to Poop Allday) — essentially the poop is like the energy produced
Electrons come in with high energy and leave with low energy in this complex. There’s only one in the PETC (of use at least)
Cytochrome complex
What is the name of the high energy electron carrier?
NADPH
- formed from (NADP+) + (H+)
How is ATP formed?
By breaking down ADP + Pi (like in cellular respiration) through the ATP synthase.
- just that it occurs in the mitochondria for animal cells and it occurs in the chloroplast for plant cells
What is the concentration gradient between stroma and thylakoid space (space within the thylakoid where protons are pumped.
Thylakoid space = High H+ (because thylakoid membrane has more electrons)
Stroma = Low H+
This is the process of fixating (splitting) carbon to produce carbohydrates/glucose (which is the plant’s food source)
- fixation is done through the formation of NADPH and ATP
Calvin Cycle *occurs in the stroma
- also known as Dark Reaction as no need for light
What are the sequence of events in the Carbon Cycle?
Fixation — Reduction — Regeneration
- poodle becomes FRREe!
What are the inputs and outputs of photosynthesis?
Inputs = carbon, light, water
Outputs = glucose, oxygen
What protein is responsible for ATP generation in plant and animal cells?
ATP Synthase - which requires a proton gradient across a membrane
Origin of Chloroplasts and Mitochondria is linked to what?
Theory of Endosymbiosis. Which states that two key organelles in eukaryotes: the mitochondria and chloroplast actually came from an ancestral eukaryote DERIVED from bacteria.
- mitochondria: proteobacteria
- chloroplast: Cyanobacteria
Where do light reactions take place?
In the thylakoid membrane
Where does carbon fixation occur?
In the stroma
What are the three compartments of the chloroplast?
Thylakoid space, intermembrane space, and stroma
These reactions capture light energy and convert it into chemical energy.
Light reactions.
What do light reactions use to convert light into chemical energy? (2)
Pigment (chlorophyll) and protein complexes (like cytochromes and enzyme ATP synthase)
What are the 3 membranes of the chloroplast?
Outer membrane, inner membrane, thylakoid membrane
These are protein complexes that contain chlorophyll to absorb the light energy and produce high energy electrons.
Photosystems
High energy electrons travel through?
Photosynthetic Electron Transport Chain
High energy electrons in the mitochondria travel through?
Electron Transport Chain
What is produced in light reactions?
Oxygen and ATP and NADPH
