Save
Students also studied
INBDE Orthodontics NBDE II Review - Prosthodontics Perio Study
201 terms 69 terms Teacher 78 terms
dong_lee82 Preview melissa_jarvis7 Preview Hunter_Charters
Terms in this set (254)
Organisms that depend on an external source of organic
Heterotrophs
compounds
Organisms capable of surviving on CO2 as their principal carbon
Autotroph
source.
Use energy from inorganic molecules (such as ammonia,
Chemotrophs
hydrogen sulfide, or nitrites) to convert into organic compounds.
use radiant energy to make organic compounds.
Phototrophs - Plants and eukaryotic algae, various flagellated protists, and
members of several groups of prokaryotes.
Photosynthesis Conversion of light energy from the sun into chemical energy.
Utilized hydrogen sulfide (H2S) as their source of electrons for
photosynthesis.
What did the first groups of lightCO2 + 2H2S → (CH2O) + 2S where (CH2O) represents a unit
photoautotrops used for of carbohydrate
energy? ▪ Nowadays, H2S is neither abundant nor widespread, so green
sulfur bacteria are restricted to sulfur springs and deep-sea
vents.
Cytoplasmic organelle located in the mesophyll of cells of
Chloroplasts leaves.
There 20-40 per cell
By fission from preexisting chloroplasts, or their nonpigmented
How did the chloroplast arise?
precursos (proplastids)
membranes of chloroplast and outer envelope: several different porins
what they contain inner: highly impermeable; a variety of transporters
thylakoid: an internal membrane system separated from the
double-layered envelope, organized into flattened membranous
sacs when arranged in orderly stacks called grana.
Internal membrane system of
-It contains photosynthetic machinery such as pigments, electron
chloroplast
carriers, and ATP synthesizing apparatus
-The thylakoid membranes have a high content of galactose-
containing glycolipids
Where is chlorophyll found? thylakoid membrane
lumen
What is the space inside the
thylakoid sac called?
,What is the space outside of the Stroma, contains the enzymes responsible for carbohydrate
thylakoid but within the synthesis
chloroplast envelope called?
tRNAs, rRNAs, ribosomal proteins, or genes involved in
What does chloroplast DNA
photosynthesis
contain?
It is a relic of the genome of an ancient bacterial endosymbiont
What does membrane fluidity Lateral diffusion of protein complexes through the mebrane
facilitate? during photosynthesis
What are the components of the Small, double stranded circular DNA molecules and prokaryotic
stroma? like ribosomes.
a redox reaction, H2O is oxidized, CO2
What type of reaction is is reduced
photosynthesis? -Transfers an electron from water to
carbon dioxide
Where is O2 derived in From the breakdown of two H2O molecules by the absorption of
photosynthesis? light
light dependent: sunlight is absorbed and converts ATP and
NADPH
two stages of photosynthesis
light independent: use the energy stored in ATP and NADPh to
yield carbohydrates
Absorption of light particles o from the ground state to the
What happens to the state when
excited state. Here an electron becomes sufficiently energetic to
a photon is absorbed?
be pushed from an inner to an outer orbital
1. porphyrin ring that absorbs light
structure of chlorophyll 2. hydrophobic tail embedding it to the photosynthetic
membrane
Pigments are substances that absorb visible light of different
What are photosynthetic
wavelengths
pigments?
• Energy in the photon depends on the wavelength of light
chlorophyll a: present in all O2-producing photosynthetic
Types of chlorophylls and organisms but missing from sulfur bacteria
where are they present chlorophyll b: in all higher plants and green algae
bacteriochlorophyll: only in green and purple bacteria
In the side groups attached to the porphyrin ring
How do chlorophylls differ from -The alternating single and double bonds along the ring forms a
each other structurally? cloud making it a conjugated system which allows absorption of
a range of wavelengths
Accessory pigments that absorb light in the blue-green region of
the spectrum
Carotenoids -Produce the characteristic color of carrots, oranges, and leaves
of some plants during fall
-Act as secondary light collectors during photosynthesis
degraded and aging chloroplast that are seen during senescing
Gerontoplast
of plant foliage
amyloplast
What is the plastid that lack -Synthesisses and stores starch
pigment? -For ex.: potatoes can turn green when they get too much sun
because amyloplast is turning into the chloroplast
Some types types of plastids chloroplasts, chromoplasts, amyloplasts, gerontoplast
include:
Antenna pigments
two large pigment-protein complexes act in series to raise
Photosystems
electrons from H2O to NADP+
Photosystem II boosts electrons from below energy level of water to a midpoint
, Photosystems I boosts electrons to level above NADP+
What is the flow of electrons Z scheme
from H2O to NADP+ called?
Photosystem II, a chlorophyll dimer that absorbs light most
P680
strongly at wavelength of 680 nm
Photosystem I, a chlorophyll dimer that absorbs light most
P700
strongly at wavelength of 700 nm
Where are electrons transferred primary electron acceptor
to in the reaction center?
-from water to PSII
What are the three legs of
-from PSII to PSI
electron flow?
-from PSI to NADP+
the reaction centers become positively charged and attracts
What happens to the reaction
electrons.
center when electrons leave PSI
-P680+ and P700+
and PSII?
-The primary electron acceptor becomes positive
thylakoid membrane
Where does photosystem II
-uses absorbed light energy to generate a protein gradient
occur?
across the membrane
Absorption of light by an antenna pigment.
-these pigments residue within a separate pigment protein called
What are the steps in PSII
the light-harvesting complex II
activation?
Then light energy is passed from LHCII to inner antenna
molecules. The reaction center of P680 is chlorophyll a
Excited P680 transfers energy to an electron acceptor
pheophytin molecule (Pheo); the first electron acceptor
What is the first step of
▪ This first electron transfer generates a separation of charge in
Photosystem II?
PSII which is P680+ positively charged donor and Pheo-
negatively charged acceptor
Pheo- is transferred to opposite sides of the thylakoid
membrane, where Pheo- passes an electron to plastoquinone
(PQ).
What is the second step of -the acceptance of two electrons from water and two protons
Photosystem II? from +H from stroma reduces plastoquinone to PQH2
(plastoquinol). Then this reduced molecule dissociates from the
D1 protein into the lipid bilayer
D1 and D2 proteins are associated with this step.
Where does Photosystem II step Near the stroma side of the membrane
2 occur?
Plastiquinone (PQ) lipid-soluble molecule similar in structure to ubiquinone
The redox potential of P680+ pulls electrons from water
(photolysis)
-Formation of O2 requires four electrons from H2O
How do electrons flow from
-Protons produced in photolysis are retained in the thylakoid
water to PSII?
lumen
-Oxygen produced is released as a waste product into the
environment
1. Production of O2 leads to the formation of two molecules of
PQH2.
2. Reduced PQH2 then diffuses through the thylakoid membrane,
What are the 4 transition steps binds cytochrome b6f, and releases protons to the lumen of the
from PSII to PSI? thylakoid.
3. Electrons from cytochrome b6fare passed to another carrier,
peripheral membrane protein, plastocyanin (PC).
4. Plastocyanin transfers electrons to P700+