4.1/4.2 Flashcards
Overall Reaction for Photosynthesis
6 CO2 + 6 H20 + energy —> C6H12O6 + 6 O2
What organelle does photosynthesis require?
Chloroplasts
What organisms carry out photosynthesis?
A) Some Bacteria
B) Protists (algae provide 67% of Earth’s oxygen)
C) plants
What are the two sets of reactions in photosynthesis?
- Light-Dependent (photo)
- Light-Independent (synthesis)
Light-Dependent Reactions
In photosynthesis, the reaction that traps solar energy and uses it to generate ATP and NADPH.
Light-Independent Reaction
In photosynthesis, the reaction that assimilates carbon dioxide to produce an organic molecule that can be used to produce biologically important molecules such as carbohydrates.
Stages that Make Up The Light Dependent Reaction
1) photoexcitation
2) electron transport and chemiosmosis
Photoexcitation
Absorption of a photon to “excite” an electron in chlorophyll
Electron Transport Chain and Chemiosmosis
Series of membrane bound electron carriers pumping H+ through the membrane creating an H+ gradient and NADPH; chemiosmosis: production of ATP
Grana
Stack of Thylakoids (approx. 60 chloroplasts)
Lamellae
Unstacked thylakoids between grana.
Thylakoids Membrane
A photosynthetic membrane within a chloroplast that contains light-gathering pigment molecules and electron transport chains.
Thylakoid Lumen
The fluid filled space inside a thylakoid.
Thylakoid
One of many interconnected sac-like membranous disks within the chloroplast, containing the molecules that absorb energy from the Sun.
Photon
Package of light.
Longer-wavelength photons have _________ amounts of energy and shorter wavelength photons have ________ amounts of energy.
Smaller; Larger
Pigment
A compound that absorbs certain wavelengths of visible light while reflecting others.
Photosynthetic Pigment
A compound that traps light energy and passes it on to other compounds.
Chlorophyll b and carotenoids
Act as accessory pigments.
Chlorophyll a
Only pigment that can transfer the light energy.
What two types of chlorophyll are contained in chloroplasts?
Chlorophyll a
Chlorophyll b
What happens during photoexcitation?
- Chlorophylls a and b absorb photons with energies in blue-violet and red regions of spectrum and reflect the green light.
- The photon of light striking the chlorophyll a molecule gives an electron energy and raises it to a higher potential energy level.
- Excited Electron is captured by primary electron acceptor (a compound embedded in the thylakoid membrane)