Photosynthesis PS 1 PS 2 Flashcards
Phases of Photosynthesis (5)
Light
Light Absorption
Electron Transport
Chemiosmosis
Carbon Fixation
____ of most plants are differentiated into stacked (appressed) and unstacked (nonappressed) regions.
____and ATP synthase are located almost exclusively in unstacked regions,
whereas ____ is present mostly in stacked regions.
Thylakoid membranes
Photosystem I
Photosystem II
most active photosynthetic tissue in higher plants is the ____
of leaves
mesophyll
Non-Cyclic photophosporylation (4)
Photon of light hits PS II
Electrons are excited
Electrons transfer via ___to PSII
Light hits water and releasing oxygen as a byproduct and fill in electrons of the oxidised ____
Photon Hits Chlorophyll
protein complex (electron carrier)
P680 (PSI)
Photosynthetic apparatus in Higher Plants
____ = Reaction center of chlorophyll in PS II (Excited state) transfer into an Electron Transport Chain (The source of electrons is the water molecule which is ____)
PQ =
Cyt=
PC =
____ = Reaction center chlorophyll of pS I (excited state)
FD =
NADP+ becomes ____ because it is reduced
Chl*/P680
Photolyzed
Plastoquinone
Cytochrome complex
Plastocyanin
Chl*/P700
Ferrodoxin
NADPH
Electron Transport Pahtway during light reaction of photosynthesis
Energy derived during electron transport is coupled to transfer of protons from ____ into the ____, resulting in ____ which drives ATP synthesis similar to ATP synthesis in mitochondria.
Products of the light reactions, ____ and ____, are utilized subsequently during CO2 assimilation.
stroma
lumen
pH gradient
ATP and NADPH
Photosynthetic Apparatus in Bacteria
Unlike plants there is only one reaction center in the bacteria which carry ____.
Photosynthetic Apparatus in Algae
Scheme of the photosynthetic electron transport chain with PSII, ____, PSI and ATP synthase
anoxygenic photosynthesis
Cytb6f
Photosystem II (Splitting of Water)
There are other proteins bound with PSII toward the lumen of the
thylakoid which are involved in water oxidation (____).
The absorbed photons raise the molecule, i.e., P680, from the ground state to an excited state. It is now capable of ____ water by ____, resulting in ____ of water with simultaneous release of O2 and 4H+ in the thylakoid lumen
oxygen-evolving complex, OEC
oxidizing
removing electrons
photolysis
When a molecule is oxidized, it attains net positive or negative charge?
When a molecule is reduced is it gaining or losing electron?
Net Positive, you lose electrons and electrons are negatively charged
It gains electrons, it is the addition of hydrogen atoms
Photosystem II (Splitting of Water)
The core of The OEC or Oxygen-evolving complex has the following atoms (3)
-provide electrons to ____ which extracts electrons
– Facilitate combining of OEC with oxygen atoms of water molecule
If electrons are removed directly from water one by one, this would result in formation of ____.
4 Manganese atoms
A calcium Atom
A chlorine Atom
Tyrosine Z
Free Radicals
highly reactive and unstable molecules or atoms that have one or more ____ in their outermost electron shell - making them chemically active
unpaired electrons
capable of causing chemical reactions and damage to other molecules in the body.
conditions in which free radicals are associated.
Cancer by damaging DNA and uncontrolled growth of cells
Cardiovascular diseases
Neurodegenerative diseases
Light reactions in photosynthesis if Photons hits PS I
Excitation by a photon, absorbed and transferred by antenna chlorophylls, raises electrons in ____ from ground state to an excited state
Excited electron then passes through an electron transport chain. transfer occurs through the activity of an intermediate enzyme
_____.
The enzyme FNR catalyzes transfer of electrons to NADP+ reducing it to
P700
ferredoxin-NADP reductase (FNR)
NADPH
PHOTOSYSTEM I (PRODUCTION OF NADPH)
PS I is a multiprotein complex containing at least 11 polypeptide chains. It contains many antenna chlorophylls (LHCI) and reaction center ____ which can absorb light of 700 nm.
Photosystem I (PSI) is one of the key players in the process of oxygenic photosynthesis. This large membrane protein complex utilizes light energy to transfer electrons from the _____
plastocyanin or cytochrome b6 across the _____
the stromal/cytosolic electron carriers ferredoxin
The resulting proton gradient is used for adenosine triphosphate (ATP) production by the ATP synthase, while the electrons end up in carbon fixation.
chlorophyll P700
lumenal electron carriers
photosynthetic membrane
Proton gradient. Only available when the long wavelength 700 is vavailable
Steps (3)
1 ____ in the ____
2 Transport of H+ from the ___ to the ____ during ___
3 Utilization of H+ for reduction of ___ to ___
Cyclic Electron Transport
(1) photolysis of water in the lumen,
(2) transport of H+ from stroma to the lumen during Q-cycle,
(3) and utilization of H+ for reduction of NADP+ to NADPH at the stroma side.
