Term
|
Definition
Peroxisomes
◦ Single membrane
◦ Break down fatty acids
◦ Detoxify harmful compounds |
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Term
| Describe how peroxisomes detoxify harmful compunds |
|
Definition
Contains dense grid of crystalline enzymes that modify
compounds by transferring hydrogens from detoxified
compounds to O2
to form H2O2
(HOOH), then a separate
enzyme converts this to H2O
Compartmentalization is critical
Often found near mitochondria and chloroplasts |
|
|
Term
| What occurs during photosynthesis? |
|
Definition
Converts light energy into chemical energy
6 CO2 + 6 H2O + light → C6H12O6 + 6 O2
◦ Carried out by a range of organisms |
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|
Term
| What does the stomata do in photosynthesis in plants? |
|
Definition
Pores on the surface of leaf
for gas exchange |
|
|
Term
| What does the mesophyll do during photosynthesis in plants? |
|
Definition
Tissue inside the leaf where
photosynthesis takes place |
|
|
Term
| What do chloroplasts do during the photosynthesis in plants? |
|
Definition
Photosynthetic organelle in
the mesophyll |
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|
Term
|
Definition
◦ Electromagnetic (EM) energy
Waves (and particles)
◦ Wavelength
Distance from one crest to the next
◦ Visible light: 380-750 nm
Important for life |
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|
Term
|
Definition
| It absorbs all colors except for green. |
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|
Term
| Light can be ____(three things) |
|
Definition
Absorbed
Transmitted
Reflected |
|
|
Term
| How do you evaluate absorption? |
|
Definition
| white light is put into a refracting prison, then light is sent through a chlorophyll solution and sent to a laptop |
|
|
Term
| What are three kinds of chloroplast pigments? |
|
Definition
Chlorophyll a
Chlorophyll b
Carotenoids |
|
|
Term
| What does chlorophyll a do? |
|
Definition
Directly participates in light
reactions
Blue-green |
|
|
Term
| What does chlorophyll b do? |
|
Definition
Indirectly participates in light
reactions (harvests light and passes
it to chlorophyll a
Olive-green |
|
|
Term
|
Definition
Photoprotection
Yellow and orange |
|
|
Term
| Why do leaves change color? |
|
Definition
◦ In summer, green pigments predominate, masking
yellow-orange pigments
◦ In autumn, leaves stop making chlorophyll, leaving
only carotenoids |
|
|
Term
|
Definition
◦ Pigments absorb
light to capture
energy
◦ Convert light
energy into
chemical energy |
|
|
Term
| What are the two parts of photosynthesis? |
|
Definition
| Light reactions and Calvin cycle |
|
|
Term
| What occurs during the light reactions? |
|
Definition
| – use light to generate ATP and harvest electrons from water |
|
|
Term
| What occurs during the calvin cycle? |
|
Definition
| – use the ATP and electrons to make complex sugars |
|
|
Term
| Where do light reactions occur, what kind of energy do they convert, and what does it form? |
|
Definition
◦ Occur in thylakoid membrane
◦ Convert light energy to chemical energy
Form ATP and NADPH |
|
|
Term
| Describe the light reactions |
|
Definition
| Light and water enter the chloroplast and occur in the thylakoid membrane, there NADP and ADP meet up with the light and H2O to form ATP and NADPH and release only O2 from the chloroplast |
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|
Term
|
Definition
◦ A photon of light is absorbed
◦ An electron is kicked to an orbital with more potential
energy
Ground state to excited state
◦ Electron rapidly returns to ground state |
|
|
Term
| Describe what happens to the energy that occurs in excitation |
|
Definition
Given off as heat
Given off as photon
(fluorescence)
Transferred to another
molecule |
|
|
Term
| What happens in photosystems and what are the two parts? |
|
Definition
◦ Capture excited electrons
◦ Two parts:
Light harvesting
Reaction center complex |
|
|
Term
| Describe light-harvesting complexes |
|
Definition
◦ Cluster of proteins and pigment molecules
◦ Transfer energy from excited electrons to reaction-center complex
◦ Converts light energy into potential energy in the form of excited electrons |
|
|
Term
| Describe the reaction-center complex |
|
Definition
| ◦ Converts potential energy in the form of excited electrons into potential energy in the form of chemical energy – electrons |
|
|
Term
| What does light harvesting complex harvest across the molecule? Where does it pass to? |
|
Definition
◦ Harvest light from across the molecule
◦ Pass it to the Reaction Center |
|
|
Term
| What does the reaction center complex include? |
|
Definition
◦ Complex includes:
2 ‘special’ chlorophylls
4 Manganese
1 Calcium
1 Chlorine
1 Tyrosine
1 Water
Pheophytin is initial
electron acceptor
Plastoquinone is
ultimate electron
acceptor
◦ Plastoquinone transfers
electrons to electron
transport chain |
|
|
Term
|
Definition
| The initial electron acceptor in the reaction center complex |
|
|
Term
|
Definition
| The ultimate electron acceptor |
|
|
Term
| What do plastoquinones transfer? |
|
Definition
| electrons to the electron transport chain |
|
|
Term
| Describe the Linear electron flow |
|
Definition
1. Initial absorption of light by PSII
2. Passing of electrons to primary acceptor (plastoquinone [Pq] is ultimate electron acceptor of PSII)
3. Extraction of electrons from water to restore Reaction Center Complex
4. Electron transport chain
5. Passage of protons across membrane, resulting indirectly in the generation of ATP
6. Energy from light excites an electron in PS I, which is
passed to electron acceptor (ferredoxin [Fd] is ultimate
acceptor)/ Replaced by electron from PS II
7. Second electron transport chain passes electrons reduce
NADP+ into NADPH by NADP+ reductase |
|
|
Term
| What is the problem that occurs in the linear electron flow and how do we solve it? |
|
Definition
Problem: we have a free pair of free electrons on plastoquinone and we want to add them to NADP+ to produce NADPH but the free energy of activated plastoquinone is less than that of NADPH
Solution: Use 2 steps to build enough energy to reduce NADP +..Photon goes up Photosystem 2..then goes to photosystem I to reach the NADPH |
|
|
Term
| How many photosystems do chloroplasts contain? |
|
Definition
|
|
Term
| Describe the 2 photosystems that chloroplasts contain |
|
Definition
Photosystem II:absorbance max at 680 nm
Photosystem I: absorbance max at 700 nm
Function in sequence |
|
|
Term
| Describe the geometry of linear electron flow |
|
Definition
Geometry of Linear Electron Flow
• electrons are stripped from H2O in thylakoid space, leaving protons
• electrons are passed to stroma side of membrane by PS II
• reduced plastoquinone picks up protons from stroma side
• re-oxidized plastoquinone releases protons into thylakoid space
• electrons from electron transport chain are passed to PS I on
thylakoid-space side
• electrons are passed to stroma side by PS I
• NADP+ is reduced on stroma side, taking up protons
• Net effect is production of NADPH, plus a gradient with elevated
proton levels in the thylakoid space |
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|
Term
|
Definition
|
|
Term
| describe the generation of ATP |
|
Definition
◦ Electron Transport Chain
establishes a proton gradient
◦ ATP synthase harvests the energy
to make ATP |
|
|
Term
|
Definition
◦ Multi-protein complex
in thylakoid membrane
◦ Protons move down their
gradient (high to low)
◦ Catalytic domain uses energy
to form ATP from ADP and Pi
Conversion of potential energy
(proton gradient) into kinetic
energy (rotation of enzyme
complex) and back into
potential energy (ATP) |
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