chloroplast - lecture 12 Flashcards
What are the main structures of chloroplasts?
- stroma
- Thylakoid
- Granum
- Intermembrane space
- inner and outer membranes
Why is light needed in the chloroplast ETC?
The electrons that get passed along the ETC in chloroplasts come from water. Water is a poor donor of electrons and a lot of energy is required to extract the electrons from water. The energy source to do this is light
How is sunlight utilised in chloroplast molecules?
-Sunlight is absorbed by chlorophyll molecules and electrons interact with photons of light raising them to a higher energy level
What are photosystems and what are they made up of?
- consist of an antenna complex and a reaction centre
What does the antenna complex do?
collects the energy from sunlight and channels energy to a pair of electrons in the reaction centre
What are the 3 mobile electron carriers?
- plastoquinone
- Plastocyanin
- Ferredoxin
What is plastoquinone like?
closely resembles ubiquinone of mitochondria)
Description of plastocyanin
a small copper containing protein
What is Ferredoxin?
a small protein contains an iron - sulphur centre
How is H plus generated in photosynthesis?
The splitting of water
What are the high energy electrons passed onto in the end?
NADPH
What is ATP and NADPH used for?
- carbon fixation
- for every 3 carbon sugar produced 9 molecules of ATP and 6 NADPHs are required
What does Rubisco do?
catalyses the initial reaction in carbon fixation .
Very slow enzyme .
What is Ribulose bisphosphate (RuBP)?
a 5 carbon molecule in which a carbon is added to
What happens in the thylakoid / thylakoid membrane?
Photosystems I and II,
ATP synthase, NADP reductase
What happens in the stroma?
ATP synthesised, NADPH
Synthesised, carbon fixation, DNA
What are the similarities between mitochondria and chloroplasts?
Both use proton gradients across membranes to produce ATP using ATP synthase
Electron transport along an electron transport chain drives proton pump
Similarities between some of the components of electron transport ch
What are individual characteristics about mitochondria?
High energy electrons come from NADH
Ultimate electron acceptor is O2
Chemical bond energy used in cellular processes
What are individual characteristics about chloroplasts?
Low energy electrons come from H2O but are excited to higher energy by light
Ultimate electron acceptor is NADP+
Chemical bond energy and reducing power utilised in carbon fixation
