Bio 4: Photosynthesis Flashcards
Autotrophs
Organisms that use light or chemical energy and inorganic molecules to synthesise complex organic molecules.
Heterotrophs
Organisms that ingest and digest complex organic molecules releasing chemical potential energy stored in them.
Chloroplasts
\+Disc shaped \+2-10um long \+Double membrane \+Intermembrane space 10-20nm wide \+Folded into lamellae (stack: granum) \+Stroma - fluid filled matrix \+Thylakoids
Photosynthetic pigments
Molecules that absorb light energy. Each pigment absorbs a range of wavelengths in the visible region and has its own distinct peak of absorption.
Chlorophyll
Magnesium iron in it Chlorophyll a has two forms - 680 and 700 680 is in PSII, 680nm 700 is in PSI, 700nm a absorbs blue light
Carotenoids
Carotene - orange
Xanthophyll - yellow
Light dependent stage
In the thylakoid membrane
Water (in LDS)
+ source of hydrogen ions for chemiosmosis
+ source of electrons
Photophosphorylation
Making of ATP from ADP and P in the presence of light.
Electron carriers
Molecules that transfer electrons.
Electron acceptors
Chemicals that accept electrons from another compound. They are reduced while acting as oxidising agents.
Cyclic photophosphorylation
+Only PSI
+No redNADP made
+No photolysis of water
+Small amount of ATP made
Non-cyclic photophosphorylation
+PSI & PSII
+ATP is made
+Photolysis of water
+redNADP is made
Light independent stage
Takes place in the stroma, also called the Calvin cycle. carbon dioxide is fixed and used to build complex organic molecules.
Calvin Cycle
CO2 combines with RuBP, makes GP
GP is reduced and phosphorylated making TP (+ NADP and ADP + P)
TP is phosphorylated
5/6 TP becomes RuBP
