LIGHT REACTION AND DARK REACTION Flashcards
All the food
we eat and the fossil fuels we burn
are products of ________.
photosynthesis
turn solar energy into food
which is nice of them because
animals can’t eat sunshine.
Plants
When animals eat plants and other animals,
that original solar energy is passed along
the_______ .
food chain
is the process that converts solar energy
into chemical energy that is used by biological systems
(that means us).
Photosynthesis
Photosynthesis has 3 major events:
- Sunlight is converted into chemical energy
- Water (H2O) is split into oxygen (O2)
- Carbon dioxide (CO2
) is fixed into sugars (C6H12O6)
Photosynthesis is carried out by:
certain bacteria
plants
cyanobacteria
certain bacteria
most algae phytoplankton
These organisms are known as ______ or
producers meaning they
make their own food and
energy from the sun.
photoautotrophs
Consumers such as –_______ and _____depend on the products
of photosynthesis that producers
make to live.
herbivores and
carnivores
is a
sugar and its molecular
structure looks like this.
Glucose (C6H12O6
)
produce sugars as a source of food.
However, they produce way more than they
need to survive. This is a great benefit for all
the species that depend on glucose for energy.
Plants
All biological energy comes from_____.
glucose
During photosynthesis, plants
produce _____ when
they convert light energy into
chemical energy. The chemical
energy is stored in the _______.
glucose molecules
bonds of glucose.
Plants also use the
_____ they produce for
_____. When plants
produce excess glucose
they store it in their
_____.
glucose
energy
leaves
When ____
digest plants, they
are breaking down
the glucose bonds
to release stored
energy to power
their bodies.
animals
______can be broken
apart from energy to power reactions.
Glucose molecules
Plants can also make glucose into carbohydrate
chains called _____.
polysaccharides
poly =
saccharide =
poly = many
saccharide = carbohydrate
Glucose is a _____
monosaccharide.
mono =
saccharide =
mono= one
saccharide = glucose
is a simple sugar
because it is one of the smallest
units of carbohydrates.
Glucose
There are 2 polysaccharide chains in plants:
cellulose
starch
is the structural
component of cell walls.
Cellulose
is a long term energy store that
the plant can use later.
starch
_____are full of round flattened discs
called______.
Chloroplasts,
thylakoids
are a plastid or plant cell organelle
Chloroplasts
A stack of thylakoids is called a _____.
granum.
are where photosynthesis occurs.
Chloroplasts
is the
space inside
chloroplasts
Stroma
A very long time ago, plant cells were once ancient eukaryotic cells that had enveloped a______ .
cyanobacteria
Eventually, the cyanobacteria became a part of the cell and dependent upon it for life which in turn gave the cell the ability to ______.
photosynthesize
A very long time ago, plant cells were once ancient eukaryotic cells that had enveloped a cyanobacteria. Eventually, the cyanobacteria became
a part of the cell and dependent upon it for life which in turn gave the cell the ability to photosynthesize.
This is called the _______.
(endo =)
This is called the endosymbiotic theory.
(endo = inside
are also
believed to have been
engulfed by ancient
eukaryotic cells through
endosymbiosis.
Mitochondria
Cyan comes from the Greek word cyanin which
means aqua colored.
Cyanobacteria
Not all bacteria that undergo photosynthesis are
cyanobacteria but all cyanobacteria are
photosynthetic
bacteria
are not cyanobacteria but were
the first bacteria discovered that can photosynthesize
purple bacteria
undergo photosynthesis in lakes, ponds, and
oceans.
Cynobacteria
Cyanobacteria lack
chloroplasts
Photosynthesis in plants happens in the _____.
chloroplasts
chloroplasts are full of ___ stacked in _____.
thylakoids, granum
The ______
are lined by pigments such as
chlorophyll and cartenoids.
thylakoid membranes
The thylakoid membranes
are lined by pigments such as
_______and _____.
chlorophyll and cartenoid
is a green pigment
and is the most abundant.
Chlorophyll
____absorbs all wavelength colors
except green, which is reflected off giving plants their green appearance.
Chlorophyll
These pigments harvest
light energy packets or
______when they
absorb sunlight.
photons
capture light energy to power
photosynthesis.
Light reactions or
“light dependent reactions”
Light reactions occur during the
day time
light reactions takes place in
thylakoids
Pigments in the thylakoid membranes form protein complexes called
______ and ____.
Photosystem I and Photosystem II
These photosystems harvest _____to
charge up____carrying molecules that will power the dark reactions.
photons , energy
do not need light energy to power their reactions and can occur day or night.
Dark reactions or “light independent
Discovered by three scientists, the dark reactions are also called the _____ or just _____
Calvin-Bensen-Bassham cycle or just Calvin Cycle.
Dark reactions occur in the ______ of chloroplasts (the space that surrounds thylakoids) and fix carbon dioxide into
glucose.
stroma
Energy Carrying Molecules of Light Reactions
ATP AND NADP+
can hold excited electrons (e-) charged from the light energy harvested by chlorophyll to become ____.
NADP+, NADPH
passes the electron
it’s holding to power the dark reactions
and reverts back to NADP+.
NADPH
is called the “cellular currency”
because it is used to power all the
reactions that take place in the cells
of all living things
ATP
When ______ is
broken off it releases energy that
the cell can use.
ATP’s third phosphate
is made when a third
phosphate group is added to
ADP (diphosphate, di = two
ATP
The energy absorbed by the
chlorophyll during the light reactions is used to power ______that
breaks the bonds of water absorbed
through the plant’s roots.
photosystem II
When water molecules break apart, the remaining two hydrogen atoms have a positive charge and are called .
protons
When water molecules break apart, the remaining two hydrogen atoms have a positive charge and are called protons. These protons are kept inside the ___by the_____.
thylakoid, thylakoid membrane
When there are more protons inside the thylakoid than in the stroma outside, protons
want to leave the ______thylakoid.
crowded
When the protons (H+) cross the membrane to leave, a_____ uses their passage to power ATP production
protein
The protein ____ attaches a phosphate group
to ADP (D = di or two) making it ATP (T = tri or three).
ATP synthase
The light energy absorbed by
chlorophyll also powers
_____that charges up
the energy carrier molecule
NADP+ into NADPH.
photosystem I
are absorbed by the pigments to
power photosystem I and photosystem II.
Photons
splits water molecules into
two protons (H+) and oxygen atoms are expelled as O2
gas through the stomata.
Photosystem II
______ cross the thylakoid membrane and D
power protein complex ATP synthase to make
_____
Protons, ATP
____ is powered up by photosystem I to
make _____ to be used in the dark reactions
NADP+, NADPH
_____finish with
charged NADPH, ATP, and released O2.
Light dependent reactions
_____Also called the Calvin Cycle, the_____ start and end with the same products hence “cycle”.
dark reactions, dark reactions
All the dark reactions take place in the_____ of the chloroplast.
stroma
The Calvin Cycle starts with ______ and_____. An enzyme
called ______ combines them into an unstable intermediate.
RuBP molecules and carbon dioxide molecules.
Rubisco
is the starting molecule and ending molecule of
the Calvin Cycle. It will be remade at the end of the
cycle so that the cycle can begin again
RuBP
Since the intermediate of
combined RuBP and CO2
is unstable it quickly splits in
half and form_____ which are stable.
2 molecules of 3-PGA
The_____ and _____ from the light reactions provide the energy to convert the two molecules of 3-PGA into their final form G3P
ATP and NADPH
are joined to make a glucose molecule.
2 G3P
The left overs are
reused in the light
reactions to remake
_____and___
ATP and NADPH
Not all____ is made into glucose.
G3P
The______ occurs in every stroma in every chloroplast in every plant cell every second of every day.
Calvin Cycle
____converts the
carbon from carbon dioxide
into glucose in the stroma. This
is called_____
because carbon is fixed into
another form.
The calvin Cycle
carbon fixation
is carried out in two steps.
Photosynthesis
are the producers of the biosphere creating the oxygen
and glucose needed for most organisms.
Plants
are the site of photosynthesis in plants
Chloroplasts
contain thylakoids where the light reactions take
place.
Chloroplasts
convert sunlight into ATP and NADPH.
Light reactions
The _____uses ATP and NADPH to
convert CO2
into sugar
dark reactions or Calvin Cycle
cooperate to
convert light energy into chemical energy housed in glucose.
The light reactions and the dark reaction
use glucose to power metabolic processes.
Plants and animals
The ____ provides the energy for the reaction
sunlight
Freed oxygen atoms bind with each other to form the __.
gas 02
_____is a by product of photosynthesis not used by the plant so it is released through the stomata of plants.
O2
_____ (Greek for mouth) are little pores in leaves that open and close to let oxygen out and carbon dioxide in.
Stomata
