Photosynthesis Flashcards
what is the equation for photosynthesis
6CO2 + 6H2O + (energy?) > C6H12O6 + 6O2
Van Helmont
held an experiment where he planted a willow sapling in a weighted amount of soil and added nothing but add water. After five years, the tree gained 74kg in weight but the soil lost only 52g. He concluded the tree gained all its weight with water itself
- His experiment proved the plant’s food DID NOT come from the soil. he overlooked the fact that air was also available to the water
How do plants make their food
they combine CO2 from the air and H2O (+ dissolved salts?) from the soil
Carnivore vs Herbivore
carnivore: eats other animals
herbivore: eats plants
what is the first stage by which plants make food called
photosynthesis
how is O2 produced in photosynthesis
because O2 is broken down
Photosynthesis definitiom (3)
- the process by which plants and some bacteria use chlorophyll, a green pigment, to trap sunlight energy
- endergonic
- anabolic
- a carbon dioxide requiring process that uses light energy (photons) and water to produce organic macromolecules (glucose)
what is the sunlight energy used for after it is trapped by chlorophyll
it is used to synthesize (create) carbohydrates (carbon, hydrogen, oxygen)
what do plants make when they combine co2 and h2o
they make sugar (glucose (c6h12o6))
what is the byproduct of photosynthesis
oxygen, molecules of atp, and some heat
what does it take to combine co2 and h2o? where does it come from? What is it absorbed and used by? (+2)
energy
- this energy comes from sunlight
- this energy is absorbed and used by a substance called chlorophyll
chlorophyll. where is it present
- a green coloured chemical
- present in the leaves of green plants
where is chlorophyll located
- the chlorophyll in the cells is packaged into tiny packaged called chloroplasts
- on the thylakoid membrane
chloroplast– double membrane
- evidence for endosymbiosis (independent origin)
chloroplast- lamella
connects and separates thylakoid stacks (grana)
chloroplast- stroma
has appropriate enzymes and a suitable pH for the calvin cycle (light INdependent rxn)
chloroplast- thylakoid
has ETC and ATP synthase for photophosphorylation
- photophosphorylation is the process of utilizing light energy from photosynthesis to convert ADP (+P) to ATP
- is where light DEpendent rxn happens
chloroplast- granum (3)
- stack of thylakoids
- their function is to increase SA of the thylakoids so more light can be absorbed into the chlorophyll
- ^flat membrane stacks increase SA:Vol ratio and small internal volumes quickly accumulate ions
what does the chloroplast use to do everything
photons
photon definition
: a tiny particle or bundle of electromagnetic radiation (sunlight)
where do all the reactions to combine h2o and co2 take place
chloroplast
In where, does h2o and co2 combine? what do they produce as a result
- in the chloroplast
- produced sugar (glucose)
(h2o, sunlight, and co2 go in)
leaf cell structure- highest to lowest
- cuticle
- epidermis (kinda thick layer)
- palisade cells (uppermost layers of the leaf)
- vessel (kinda middle of epidermis and spongy parenchyma but mostly spongy
- spongy parenchyma (airy thing, lower layer)
- lower epidermis
- stoma (hole made by guard cells)
- guard cells (opening of stoma)
- cuticle
function of palisade
photosynthesis
- is the top layer and tightly packed together for sunlight to come on it
function of vessel
carries water
function of stoma
gas exchange
reactants and products of light dependent rxn
reactants
- h2o
- sunlight
- (adp and nadp?)
products
- o2
- atp
- nadph
reactants and products of light independent rxn
reactants
- co2
- atp
- nadph
products
- glucose
- adp
- nadp+
what is an electron carrier
nadph
carbohydrates (4)
- what are some examples of carbohydrates
- what do carbohydrates contain
- what can living organisms do with carbohydrates
- GLUCOSE is an example of a carbohydrate
- other examples of are sucrose, starch, and cellulose (in cells)
- carbohydrate molecules contain the element hydrogen, carbon, and oxygen
- living organisms can easily change one carbohydrate into another
what happens to the glucose made by the chloroplast (3)
it is either…
- used to provide energy for the chemical processes in the cell (by respiration)
- turned into SUCROSE and transported to other parts of the plant
- turned into STARCH and STORED in the cell as starch grains
what happens to the starch in the cell in the dark?
in darkness, the starch is changed back into glucose and transported out of the cell
different uses for glucose (5)
- ENERGY (eg. seed germination)
- other sugars (fruits)
- protein (cytoplasm)
- cellulose (cell walls)
- starch (storage (eg. starch in potato))
how to plants make glucose
they combine combine co2 from air and h2o from soil (+ dissolved salts?)
what is the energy needed for photosynthesis
sunlight
what is the purpose for photosyntehsis
to convert sunlight energy and convert it to chemical energy for future use
what is sunlight absorbed by
by the chlorophyll contained in the chloroplast of the leaf
what must glucose be combines with to make other substances
must be combines with other chemical elements, such as nitrogen and potassium.
- these chemical elements are present as ions in the soil and are taken up in solution by the roots
___ from the sun is composed of all ___
white light from the sun is composed of all colors
what colored light does chlorophyll reflect? what does it absorb
reflects green light
absorbs blue and red ends of the spectrum
- absorbs yellow and blue wavelengths
what does chlorophyll a absorb
absorbs violet-blue and orange-red
(violet and orange)
(blue and red)
what does chlorophyll b absorb
blue and yellow
pigments are organized into what?
clusters called photosystems
what are the purpose of pigments
to absorb light energy
what happens when light is captured (by pigments)
the electrons from chlorophyll move to a higher energy level
how are the wavelength and energy of a photon related
as the wavelength gets longer, the energy in a photon decreases. as the wavelength gets shorter, the energy in a photon increases.
between red and green light, which has a higher energy value?
green light possessed a higher energy value than red light because it has a shorter wavelength
how is the color of light related to its energy
the color of light is DETERMINED by its wavelength. a higher wavelength has lower energy
- red light is 750nm while violet is 380nm
what pigments are present in green leaves
chlorophyll a, chlorophyll b, carotenoids, xanthophylls, and anthocyanins
why are yellow colored pigments visible in autumn
the chlorophyll pigment masks the yellow colored pigments the rest of the year besides autumn. In the autumn, chlorophyll stops being produced, so the yellow, red, and brown colors are revealed and visible
they stop producing chlorophyll because temoeratures change
what do all photosynthetic organisms have in common
they all contain the molecule chlorophyll to capture electromagnetic radiation.
- also all contain chlorophyll a?
carotenoids color
red, orange, or yellow
chlorophyll b color
blue-green. accessory pigment
xanthophyll color
yellow. accessory pigment
what is chlorophyll
the primary pigment in plants
what does atp stand for
adenosine triphosphate
what is atp composed of? (+2 more)
- atp is composed of the nitrogen base ADENINE, the pentose (5C) sugar RIBOSE, and 3 phosphate groups
- the last phosphate group (the one on the outside) is bonded with a higher energy chemical bond
- this bond can be broken to release ENERGY for CELLS to use
What happens when a phosphate group is removed from atp
- releases energy for cells to use
- forms adp
- produces free phosphate group
ATP form thing
P+P+P—- Ribose—- Adenine//Adenine
Phosphorylation
a process where
- a free phosphate (inorganic phosphate?) can be re-attached to ADP, reforming ATP
- (?) needs energy from sunlight or food
NADP+
- what does it stand for
- what does it form and do
- stands for Nicotinamide dinucleotide phosphate
- NADP+ accepts one hydrogen ion (H+) and two electrons to form NADPH
- Can then donate electrons to other molecules
Anabolic
- small molecules combined
- a process where simple molecules combine to generate complex molecules
- photosynthesis is anabolic because photosynthetic organisms use sunlight energy to convert carbon and water to form glucose and oxygen
Endergonic
- stores energy
- basically saying it needs energy to proceed.
- a reaction where energy is absorbed
- photosynthesis is an endergonic process because it uses sunlight to do its stuff
where does photosynthesis mainly occur in the leaf
in the palisade cell and stoma (pores)
- + chloroplast??
what are plants and how do they relate to food
plants are autotrophs, meaning they produce their own food. The food being glucose
draw a labelled diagram of:
- leaf cell structure
- chloroplast
- light in/dependent rxn
- palisade cell of a leaf
a
stomata
pores in a plant’s cuticle through which water vapour and gases (CO2 and O2) are exchanged between the plant and the atmosphere
chloroplast
organelle where photosynthesis takes place
- double membrane
thylakoid- grana
grana make up the inner membrane
how is the sun related to energy for all life on earth
sun is the ultimate energy for all life on earth
where do plants store energy (+1)
in the chemical bonds of sugars
- chemical energy is released as ATP during cellular respiration
what two reactions make up photosynthesis
light rxn/light dependent rxn and calvin cycle/light dependent rxn
light dependent rxn use
produces energy from photons in the form of ATP and NADPH
calvin cycle/light independent rxn
- also called carbon fixation or C3 fixation
- uses energy (ATP and NADPH) from light r xn to make sugar (glucose)
Where does light rxn and light dependent rxn occur
light rxn
- thylakoid membrane
light dependent
- stroma
steps to light rxn (9)
- light strikes PSII and it is absorbed. This excites the electrons in the chlorophyll, which is in each PS (photosystem)
- The chlorophyll loses its electrons, which flow INTO the PQ but THROUGH the electron transport chain (ETC). Lost energy from the electrons is used to pump H+ into the lumen (from stroma). These hydrogen ions are used to produce ATP using the ATP synthase
- In regard to PSII losing electrons, it needs to replenish the lost electrons. It does this by taking the electrons from water and oxidizes it into oxygen gas. One h2o molecule makes one oxygen atom (1/2 o2) and gives off 2 hydrogen ions (H+). So basically, water loses 2 electrons to PSII with one oxygen atom as a product
- Anyways, the electrons move through another protein called Cyt and this protein pumps H+ into the lumen from the stroma
- The electrons flowing through ETC are moved to another photosystem (PSI). By now, the elctrons have lost its energy so PSI is struck by other photon of light in PSI
- Electrons move through another ETC, into another protein (Fd) which carries the electrons to NADP+ reductase
- NADP+ reductase is an enzyme that REDUCES NADP+. The electrons leave and meet up with NADP+. the NADP+ accepts the electrons (2) along with a hydrogen ion and is reduced into NADPH. this reaction also reduces H+ concentration in the STROMA
- The H+ in the stroma move down its concentration gradient and flow through the ATP synthase (enzyme).
- As the H+ floats through the enzyme, the protein rotates in a way that it combines ADP and phosphate to make ATP. the H+ plays a role in this procedure because it is the energy source to produce ATP
- the NADPH and ATP go to the light independent rxn in the stroma
PSII vs PSI
h2o is split in PSII and atp is made
the energy carrier NADPH is made is PSI
chemiosmosis
- the process of the diffusion of H+ protons through a selectively - permeable membrane
- powers ATP synthase
- takes place across the thylakoid membrane
- uses ETC and ATP synthase complex (enzyme)
- H+ move down their concentration gradient through channels of ATP synthase, forming ATP from ADP
If the light keeps on striking PSII, ejecting high energy electrons, wont the chlorophyll eventually run out of electrons?
yes, except that the electrons are replaced by using some from h2o
photolysis
- photo=light
- lysis=break
- photolysis: the breaking of a water molecule using light energy
- occurs in the lumen of the thylakoid
what goes in and out of photolysis
in:
- light photons
out:
- 2 electrons
- 2 hydrogens
- one oxygen molecule (1/2 O2)
for the 1 molecule of oxygen, it waits for another oxygen to make O2 and then leaves the plant
Calvin cycle steps
occurs in the stroma // C3 plants– 80% of all plants on earth
1. Enter RuBisCO and 3 molecules of CO2. Starting materials: CO2, RuBP (5 Carbons)
2. RuBisCO holds 1 carbon atom from CO2 molecule with RuBP to make C6. This is called carbon fixation because carbon is “fixed” by RuBP. fixed meaning to be incorporated into an organic molecule
3. C6 is so unstable that it quickly splits into 2 molecules of C3, which is called phosphoglycerates (PGA)
4. Uses ATP and NADPH from light reaction as energy: PGA USES ATP to remove the hydrogen from NADPH and affixes1 hydrogen to each of the PGA chains (the 2 C3’s). So essentially, NADPH loses 2 electrons
4.5. The way the cycle used ATP and NADPH turned them both into ADP and NADP+
5. The added hydrogen to PGA turns it into molecules called PGAL, AKA G3P (aka phosphoglyceraldehyde)
6. In 6 carbon cycles, 12 PGAL’s are formed. 2 are used to make glucose (because 1 molecule of PGAL has 3 carbons(C3)) while the 10 left are used to recycle into RuBP (needs 5 carbons). (10x 3 = 30. 6 calvin cycles = 5. matches perfectly)
what goes in and out of the calvin cycle
in:
- 3 (18?) atp
- 2 nadph
- co2
out:
- glucose
- co2 must be readily available in the stroma so it can diffuse directly into the leaves from the stroma
how many turns of the calvin cycle does it need to make one glucose
it takes 6 turns.
- 18 atp and 12 nadph are used
- 12 PGALs are produced
after PGAL is produced from calvin cycle, where does it go?
after 6 turns of calvin cycle (needed to make 1 glucose), 12 PGAL is produced.
- 2 PGALs are used to make glucose (6 carbon because PGAL has 3 carbon each and glucose needs 6 carbon)
- 10 are to go recycle RuBP (5 carbon needed for RuBP, each PGAL has 3 carbon, so 10x3=30. 30/6 (6 calvin cycles). so its enough for it do do it again.
- ^ the 30 leftover carbon is a by-product
Pgal can be used as an energy source in cell respiration
it can also be modified to produce fat or protein
what is the enzym that converrs h20 into o2 gas
PSII
splitting of water, creating waste oxygen
photolysis
what is the energy currency of cells
atp cus they b spending it
organisms use photosynthesis to make food
autotrophs
first stage of photosynthesis
light dependent rxn
how is atp generated
adp + free phosphate grp.
this process requires energy, while the splitting of atp, making adp, release energy
conversion of light energy to chemicala bond energy of organic materials
photosynthesis
hydrogen acceptor
nadp+
rubp acts as a…
carbon acceptor
- carbon + rubp = c6
process by which energy is released to support cellular activities
cr
rxns during photosynthesis in which carbon is fixed
- light independent rxn
or rubp
rxns not inovlving co2 but involves water, light, and chlorophyll
light dependent rxn
COMBINES w co2
rubp
molecules combined to form glucose
PGAL
which color of light is LEAST effective in photosynthesis
green cus green plants reflect green light
the red, orange, and yellow color in leaves are caused by light reflected from
carotenoids cus they are yellow, red, and orange
what is the source of protons for the proton gradient within a chloroplast
h2o cus it has hydrogen and it is oxidized by PSII in light rxn
how many carbon atoms are there in a molecule of RuBP
5
plants STORE glucose as…
starch
what is synthesized in the light independent rxn of photosynthesis
carbohydrated
when a photon of _____ is absorbed vy a pigment, one of the pigment’s electrons is elevated to a state in which it has more _____
when a photon of LIGHT is absorbed vy a pigment, one of the pigment’s electrons is elevated to a state in which it has more ENERGY
in light dependent rxns, ____ enegry is absorbed and briefly stored in the molecules ____ and _____
light
atp
nadph
in light dependent rxn, energy stored in ____ and ____ is used to build ____
atp
nadph
carbohydrates/pgal/g3p
