Chapter 10: Photosynthesis Flashcards
The energy in the food you eat was
“captured” by plants during what
photosynthesis
You extract the energy via what
cellular respiration.
“self-feeders” that sustain
themselves without eating anything derived
from other organisms
autotrophs
using the energy of sunlight to make organic
photoautotrophs
Researchers are exploring methods of using
the photosynthetic process to produce what
alternative fuels
obtain organic material from other
organisms
heterotrophs
are the consumers of the biosphere
heterotrophs
consume dead organic material or feces
decomposers
Almost all heterotrophs, including humans,
depend on what for food and Oxygen
photoautotrophs
make up the highest plant productivity
on earth!
Marine and aquatic algae
are the major locations of photosynthesis in
plants
leaves
the interior tissue of the leaf
mesophyll
CO2 enters and O2 exits the leaf through microscopic pores called
stomata
dense fluid
stroma
are connected sacs in the chloroplast
that compose a third membrane system
thylakoids
the pigment that gives leaves their
green color, resides in the thylakoid membranes
chlorophyll
what kind of process is photosynthesis
endergonic process
are substances that absorb visible light
pigments
Wavelengths that are not absorbed are
reflected or transmitted
measures a pigment’s ability to absorb various wavelengths
spectrophotometer
sends light through pigments and
measures the fraction of light transmitted at each
wavelength
spectrophotometer
radiant energy
light
what does light exist as
photons
The complete range of light
is called the
electromagnetic spectrum
What happens when photons hit
an object?
1) They are reflected
2) Or they are absorbed
3) Or they pass right through
what they hit! (transmitted)
the key light-capturing pigment
Chlorophyll a
an accessory pigment
Chlorophyll b
may broaden the spectrum of colors that drive
photosynthesis
caroteniods
type of Chlorophyll b
caroteniods
they
absorb excessive light that would damage
chlorophyll or react with oxygen
photoprotection
what happens when a pigment absorbs light?
it goes from a ground
state to an excited state, which is unstable
When excited electrons fall back to the ground state, excess energy is released as what?
heat
In isolation, some pigments also emit light, an
afterglow called what?
fluorecence
what are the two main phases of Photosynthesis?
Photosystems and Calvin Cycle
describe the light in photosystems
its dependent of RX
what is the job of photosystems
Convert solar energy to chemical energy
What are the products of photosystems
O2, ATP, NADPH
describe the light the Calvin Cycle
its independent of RX
where is the Calvin cycle located
Stroma (a dense fluid) in
Chloroplast
what does the Calvin Cycle do
Carbon fixation produces glucose
products of the Calvin cycle
glucose
input of Calvin cycle
CO2
NADPH
consists of a reaction-center
complex surrounded by light-harvesting complexes
photosystem
consists of pigment
molecules bound to proteins
light-harvesting complex
transfer the energy of
photons to the chlorophyll a molecules in the
reaction-center complex
light-harvesting complex
accepts excited electrons and is reduced as a result
primary electron acceptor
where is the primary electron acceptor located
the reaction center
the first step of the light reactions
Solar-powered transfer of an electron from a
chlorophyll a molecule to the primary electron
acceptor
two types of photosystems in the thylakoid
membrane
Photosystem II and Photosystem I
what photosystem functions first
Photosystem II
The reaction-center chlorophyll a of PS II is called what
P680
why is the reaction-center chlorophyll a of PS II is called P680
because it is best at absorbing a wavelength of
680 nm
reaction-center chlorophyll a of PS I is called what
P700
electrons excited by sunlight energy release energy as electrons passed down ETC
photophosphorylation
what does the linear equation electron flow use?
Utilizes both photosystem I & II
what does the linear equation electron flow produce
NADPH & ATP in equal amounts
what does the Cyclic Electron Flow use?
Only utilizes photosystem I
what does the linear equation electron flow produce
Produces ATP – makes up difference needed for
Calvin Cycle
what does the calvin cycle require more of?
ATP
Photons w/ wavelengths of
680 nm excite electrons in what
PS II
Produces additional ATP’s needed to
perform Calvin Cycle
Cyclic Electron Flow
how does the cyclic electron produces additional ATP’s needed to
perform Calvin Cycle
Excited electrons from PS I enter into
previous ETC, which releases ATP as it
is passed along
where is the calvin cycle located?
in the storma in chloroplast
what is the impute for calvin cycle
CO2 and NADPH
what is the calvin cycle output
glucose
regenerates its starting material after molecules
enter and leave the cycle
calvin cycle
how is the Calvin cycle anabolic?
its builds sugers from smaller molecules using ATP and NADPH
where are Dark or Light Independent
reactions located?
stroma of chloroplast
highly regulated enzyme pathway
enzymes use ATP and NADPH to produce glucose
occur in the presence or absence of light
three stages of calvin cycle
carbon fixation
reduction
regeneration of CO2 acceptor
CO2 fixed from atmosphere by RuBP
catalyzed by enzyme Rubisco
carbon fixation
ATP phosphorylation and NADPH reduction to form G3P (Glucose precursor)
Reduction
Some G3P is phosphorylated by ATP in
order to reform RuBP
Regeneration of CO2 acceptor
NAD+ & ADP reused by
photosystems I & II
At high temps or during droughts, stomata stay closed.
leads to Photorespiration and a loss of productivit
