Topic 8.3 - Photosynthesis Flashcards
Where do light-dependent reactions take place?
In the intermembrane space of the thylakoids
How long can the light-independent reactions carry on in darkness?
A few seconds
Why do the light-independent reactions carry on for a few seconds in the darkness
Because they depend on substances produced by the light-dependent reactions which rapidly run out
Briefly outline the structure of the chloroplast and the location of thylakoids
The chloroplast has an outer membrane and an inner membrane. The inner membrane encloses a third system of interconnected membranes called the thylakoid membranes. Within the thylakoid is a compartment called the thylakoid space.
Where do the light-dependent reactions take place?
In the thylakoid space and across the thylakoid membranes
What is produced in light-dependent reactions?
Light energy is converted into chemical energy in the form of ATP and reduced NADP
What does energy in the form of ATP and NADPH serve as?
Energy sources for the light-independent reactions
Where do the light-independent reactions take place in?
In the stroma
Outline details of the stroma
The inner membrane of the chloroplast encloses a compartment called the stroma.
- it is a thick medium
- protein rich
- contains enzymes for use in the light-independent reactions.
What is the Calvin cycle?
- an anabolic pathway
- requires endergonic reactions to be coupled to the hydrolysis of ATP and the oxidation of reduced NADP
Briefly outline the steps of the light-dependent reactions
- photolysis
- photoactivation
- electron transport
- chemiosmosis
- ATP synthesis
- reduction of NADP
Briefly outline the steps of the light-independent reactions
- carbon fixation
- carboxylation of RuBP
- production of triose phosphate
- ATP and NADPH as energy sources
- ATP used to regenerate RuBP
- ATP used to produce carbohydrates
What generates excited electrons in the light dependent reactions?
absorption of light by photosynthesis
What are photosystems?
They are light-harvesting arrays that contain chlorophyll and accessory pigments grouped together
Location of photosystems
In the thylakoids, an arrangement of membranes inside the chloroplast.
