• Some molecules act as energy carrier molecules (receive energy in the form of electrons and transfer them to some other part of the cell) Phosphate groups commonly serve as energy carriers (they resemble hydrogen ions in this manner) Phosphorylation is the addition of a phosphate group to a molecule, thereby reducing the target molecule (increasing its energy) and reducing the original carrier of the phosphate group (decreasing its energy) Energy in Cells Phosphate group
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Some molecules act as energy carrier molecules (receive energy in the form of electrons and transfer them to some other part of the cell) Phosphate groups.
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• Some molecules act as energy carrier molecules (receive energy in the form of electrons and transfer them to some other part of the cell)
Phosphate groups commonly serve as energy carriers (they resemble hydrogen ions in this manner)
Phosphorylation is the addition of a phosphate group to a molecule, thereby reducing the target molecule (increasing its energy) and reducing the original carrier of the phosphate group (decreasing its energy)
Energy in Cells
Phosphate group
• Common Energy Carrier Molecules:
ATP ADP + Pi + energy (e-) ADP + Pi + e- ATP
FADH2 FAD + 2H+ + 2e- FAD + 2H + 2e- FADH2
NADH NAD+ + H+ + 2e- NAD+ + H + 2e- NADH
Energy in Cells
Photosynthesis is the conversion of energy from light into chemical energy stored in glycosidic bonds
6H20 + 6CO2 + light C6H12O6 + 6O2
Light-independent (dark) reactions
glucose
Granum
oxygencarbon dioxidewater
Photosynthesis KNOW THIS SLIDE!
• Have double membrane (inner and outer)• Grana (stacks of thylakoids) – membrane
of these is where light reactions of photosynthesis occur
• Chlorophyll – light-absorbing pigment in thylakoids• Stroma – fluid that fills chloroplasts
surrounding the grana – where light independent reactions occur (also known as the Dark Reactions or Calvin Cycle)
PhotosynthesisChloroplasts (plant cells and photosynthetic protists)
(Calvin Cycle)
Thylakoid Stroma
energy carrier
molecules
Light-Dependent Reactions of Photosynthesis(Occur in the grana via proteins embedded in the thylakoid membranes)
1. Photosystem II: Energy from light is absorbed by chlorophyll molecules in the Photosystem II
protein complex embedded in the membrane of the thylakoids the energy is transferred to electrons taken from breaking water (H2O) into 2 H+ ions
plus one oxygen atom two of these oxygen atoms later combine to form O2 gas which is then released into
Light-Dependent Reactions of Photosynthesis(Occur in the grana via proteins embedded in the thylakoid membranes)
4. ATP Synthase: H+ ions trapped inside the positively charged thylakoid want to get away ATP Synthase proteins embedded in the membrane provide a passage for the H+
ions to escape, and as they do, they cause an inner part of the protein to spin Energy from this spinning protein is used to add phosphate groups to ADP
molecules in order to create the energy carrier molecules ATP (much in the same way that water or wind turns turbines to create energy)
Light-Dependent Reactions of Photosynthesis(Occur in the grana via proteins embedded in the thylakoid membranes)
1. Light excites the electrons in chlorophyll (photons are converted into chemical energy)2. Excited electrons are passed down electron transport chain (ETC)
(e- are replaced with e- from splitting water, which is why O2 is released)3. Electron transport chain pumps protons (H+) into thylakoid - H+ ions from splitting water
are also released into thylakoid – results in concentration gradient (+ charge on one side) 4. Energy is captured in carrier molecules:
NADPH is synthesized at third ETC protein using energy from the excited e- passed down the Electron Transport Chain in addition to another photon from light)
ATP is synthesized using energy from H+ leaving thylakoid through ATP synthase 5. Carrier molecules (NADPH and ATP) move to stroma to power carbohydrate synthesis
(building sugars) via the Calvin cycle (dark reactions)