What is part of photosynthesis called that uses light directly?
What is part of photosynthesis called that does not use light directly?
What are light independent reactions dependent on?
can work in dark but only shortly, need substances produced by light dependent reactions
what does the inner membrane of a chloroplast enclose?
third system of interconnected membranes called thyla koid membranes
What are thylakoid membranes?
third system of interconnected membranes enclosed by inner membrane of chloroplast
What is within thylakoid?
compartment called thylakoid space
What are the products of light dependent reactions
light energy converted into chemical energy in form of ATP and reduced NADP
What do ATP and NADP serve as for light independent reactions?
What is a stroma
compartment which inner membrane of the chloroplast encloses; protein rich with enzymes to use for calvin cycle (light independent reactions)
What is the calvin cycle?
anabolic pathway for light independent reactions that require endergonic reactions so that ATP is hydrolised and reduced NADP is oxidized
What are photosystems?
chlorohyll and accessory pigments grouped together in large light harvesting arrays (contain chlorophyll)
Where are photosystems located?
in thylakoids, an arranment of membranes inside chloroplast
What do photosystems I and II have?
light harvesting arrays (with chlorophyll), reaction centres and many chlorophyll molecules that absorb light energy
What happens when chlorophylls in the reaction centre absorb energy?
when energy is absorbed from photon of light an electron within molecule gets excited. which makes chlorophyll photoactivated
How can a chlorophyll get photoactivated?
chlorophyll absorbs energy from photon of light, electron gets excited
What is a special property of chlorophylls in the reaction centre?
can donate excited electrons to electron acceptor
What is the electron acceptor of photosystem II called?
What does plastoquinon do?
collects to excited electrons from photosystem II, then moved to another position in the membrane
Describe a property of plastoquinone
Hydrophobic; has no fixed position but remains within mmbrane
what does the absorption of two photons of light cause?
produces one reduced plastoquinone, where chlorophyll at reaction centre lost 2 electrons to plastoquinone
Can photosystem II repeat the process of producing a new plastoquinone?
Yes it can repeat the process and produce a second reduced plastoquinone
What does photo phosphorylation produce?
ATP using energy from light
Who carries out phosphorylation?
What does a thylakoid membrane include?
photosystem II; chain of electron carriers; photosystem I; ATP synthase
How are electrons carried from reaction centre of photosystem II to chain of electron carriers?
reduced plaetoquinone is needed
What happens once plastoquinone transfers its electrons?
electrons are passed from carrier to carrier in chain
What happens when electrons pass through the electron carrier chain?
energy is released from excited electrons from photosystem II which provides protein pumps to pump H+ across thylakoid membrane the lumen of the thylakoid; concentration gradient developed;
How is a concentration gradient created across the thylakoid membrane?
excited electrons from photosystem II is passed along electron carrier chain (cytochrome complex) which releases energy that actively transports H+ across membrane into lumen; photolysis also increases H+ concentration
How is ATP generated in thylakoids?
High concentration of H+ in thylakoid space is reduced by passing them through the enzyme ATP synthase; energy is released through the passive transport of H+ (down concentration gradient) synthesizes ATP from ADP +Pi
What is the process called when H+ passes through ATP synthase from high concentration to low, to convert ADP to ATP