Chapter 6: Photosynthesis Flashcards
Earliest living organisms were ______
heterotrophs
chemoautotrophs
use energy from inorganic molecules
photoautotrophs
use radiant energy to make organic compounds
electron source of first autotrophs
H2S
Photosynthesis reaction
6CO2 + 6H2O –> C6H1206 + 6O2
Photosynthesis in eukaryotes takes place in the ________
chloroplast
T/F: the inner membrane of the chloroplast is permeable to large molecules.
False. The OUTER membrane of the chloroplast contains PORINS and is permeable to large molecules.
The inner membrane of the chloroplast is folded into flattened sacs called ________, arranged in stacks called __________
The inner membrane of the chloroplast is folded into flattened sacs called THYLAKOIDS, arranged in stacks called GRANA.
Do chloroplasts contain their own DNA?
yes. Chloroplasts are self-replicating organelles.
What makes the thylakoid membrane highly fluid for diffusion of protein complexes?
The large percentage of glycolipids in thylakoid membrane.
Matrix is to mitochondria as _______ is to chloroplasts.
STROMA
Where is ATPase located in the chloroplast?
The thylakoid membrane
Photosynthesis oxidizes _____ to _______
Photosynthesis oxidized WATER to OXYGEN.
In the light-dependent reactions, sunlight is absorbed and converted into _______ and _________
ATP and NADPH
In the light-independent reactions, ATP and NADPH are used to produce ____________
carbohydrates
What are photosynthetic pigments?
molecules that absorb light of particular wavelengths
Purpose of rign and tail on chlorophyll
- PORPHYRIN RING absorbs light.
- Hydrophobic tail is embedding chlorophyll to the photosynthetic membrane.
Conjugated system in porphyrin ring
Conjugated system = alternating single and double bonds along the porphyrin ring form a cloud. These systems absorb energy of a range of wavelengths.
Carotenoids
accessory pigments which absorb blue-green spectrum of light.
Antenna pigment
Pigments that do not directly participate in the conversion of light energy.
Responsible for light ABSORPTION.
The reaction center of PSII is referred to as ____ because…
The reaction center of PSII is referred to as P680 because it is the wavelength where ABSORPTION is STRONGEST.
The reaction center of PSI is referred to as ____
P700
The flow of electrons from H2O to NADP+ is referred to as _________
the Z Scheme
Two proteins that bind to P680 are called ____ and ______.
D1 and D2
What is LHCII?
“Light Harvesting Complex II”
- A pigment-protein complex OUTSIDE of PSII
- LHCII proteins bind both chlorophylls and carotenoids
- excitation energy is passed from the outer-antenna pigments of LHCII to inner-antenna chlorophyll molecules in PSII and then to P680. The excited reaction center pigment then responds by transferring a single excited electron to the primary electron acceptor (pheophytin)
What is the primary electron acceptor of P680 reaction center?
Pheophytin
Pheo- transfers its electron to ________
Pheo- transfers its electron to Plastoquinone (PQa)
T/F: plastoquinone is lipid-soluble
true
3 states of plastoquinone
- Plastoquinone: fully oxidized (0 e-)
- Plastosemiquinone: 1 e-
- Plastoquinol: Fully reduced (2e-)