c1.3- photosynthesis Flashcards
where does oxygen come from in the process of photosynthesis
photolysis
photolysis
using energy from light to split water
what plants would have to separate the two processes
desert plants, CAM plants
y do some plants have to separate the two processes
would have to open stomata in light independent reaction since they need co2 and will transpire away too much water
chemical store of energy in plant
starch
polysaccharide molecules found in plants
starch and cellulose
what bond is made during hydrolysis
glycosidic bond
y need boil before testing for starch
break down cell wall
preparation before testing for starch
- de-starch
- boil
- boil in ethanol
use of ethanol when testing for starch
remove chlorophyll- observe colour change
high frequency radiation
many waves per unit so a lot of energy
red
low frequency radiation → low energy → too low to be used in most living organisms
what types of lights are harmful [3]
uv
x rays
gamma rays
why are uv, x rays and gamma waves harmful to living organisms
encourage cell and dna damage
- skin cancer and tumours
purpose of pigments in photosynthetic organisms
- absorb useful wavelengths of light (those that contain energy appropriate for photolysis)
- absorb different colours of lights
dominant pigment in leaves
chlorophyll
why are leaves green
green wavelength is not absorbed, only red and blue is absorbed
white wavelengths
reflects all wavelengths
absorption spectrum
range of wavelengths that are absorbed by chlorophyll
x and y axis of absorption spectra
x- wavelength (nm)
y- absorption (Abs)
x and y axis of action spectrum
x- wavelength (nm)
y- rate of photosynthesis (or smth else)
y do leaves change colour in the fall
less sunlight → chlorophyll breaks down so reveal other pigments in leaves
more than one pigment in leaves
action spectrum
range of wavelengths of light which can be used in the light dependent reactions
purpose of sodium hydrogen carbonate in experiment
generate co2
how to control light intensity
change distance from lightbulb
why need to stop chromatography
every colour will go to the top
3 living organisms that do photosynthesis
- plant
- algae
- cyanobacteria
role of PQ
accept electron and carry it to the proton pump
where is the proton pump
thylakoid membrane
photosystem I
give energy using light energy → electron in excited state
role of ferredoxin
- use electron to convert NaDP+ -> NaDPH + H+
- reduction
photosynthesis reaction steps [6]
- photolysis
- oxidises water -> hydrogen and oxygen
- electron excited state bc of light - Pq carries electron to proton pump
- concentration gradient of hydrogen ions created
- Pc carries electron to photosystem I
- feeredoxin: NADP+ reduced
- atp synthase
- chemiosmosis
photosystem I
non-cyclic photophosphorylation
not enough NaDP+
- excited electrons go back from photosystem I back to proton pump
- process stops at ferredoxin
problem with too much light
- reduced all of NaDP+
- cant waste the light
loop of photosystem I
excited back to pump → lose energy → stuck
- while hydrogen go through from the pump
where does the light independent reaction occur
stroma
where is chlorophyll found
thylakoid in chloroplast
what happens to an electron when its excited by photons of light
photoactivated
increases in energy level as it travels to different chlorophylls
eventually released from the photosystem from the reaction centre
name of the 5-carbon compound present in the Calvin cycle
RuBP
when does carbon fixation occur
RuBP reacts with carbon dioxide to form a 6-carbon compound, which is then broken down into two glycerate-3-phosphate
enzyme responsible for fixing co2
rubisco
what does the structure of cellulose allow it to do
allow bundles to form using hydrogen bonds (polar)
products of light dependent reactions which are carried through to the light independent reactions
NADPH
H+
ATP
reactants and products of rubisco
from RuBP + CO2, make glycerate-3-phosphate
co2 conc- result on rate of photosynthesis
more substrate for rubisco to form RuBP to make glycerate-3-phosphate
rate
speed of which reactants are converted to products
higher temperature- result on rate of photosynthesis
- more kinetic energy, more collisions between enzymes and substrates involved in photosynthesis
- higher rate of photosynthesis until past the optimum temperature
more light- result on rate of photosynthesis
- more energy for photoactivation and photolysis
- higher rate of light dependent reaction
absorption spectrum
shows the wavelength of light that is absorbed by plants
waste product from photosynthesis + why its considered to be a waste product
oxygen, not needed for the rest of the photosynthesis process
energy of wavelengths of light form low to high
infra-red → ultraviolet
frequency of wavelengths of light from low to high
infra-red → ultraviolet
y photosynthesis consumes energy
- photon will be used to generate atp in light dependent reaction
- required to form triose phosphate from glycerate-3-phosphate in the light dependent reaction
photosynthesis
production of carbon compounds in cells using light energy
2 main uses of glucose produced in photosynthesis
respiration, growth
y light independent reaction make glucose phosphate and not glucose
glucose phosphate can stay in long enough to be converted to starch + doesnt affect water potential
what happens when there is too much glucose
lost right away → cant make starch
where does calvin cycle occur
stroma
why NADP+ reduced
generate high energy electrons
what is also needed during carbon fixation in calvin cycle
atp
y does cyclic phosphorylation occur
when theres not enough NADP+
wavelength of red light comparatively to blue
longer
- lower energy
what happens to water in photolysis
oxidised
what does ferredoxin use
electron
photosystem I
cyclic photophosphorylation
reaction of carbon fixation
6RuBP + 6CO2 -> 12 glycerate-3-phosphate
function of rubisco
fixes co2
photosynthesis
production of carbon compounds in cells using light energy
what is glucose used for
respiration and growth
role of NADH + H+ in aerobic cell respiration?
to transfer hydrogen to the electron transport chain
advantage of having a small volume inside the thylakoids of the chloroplast?
high proton concentrations are rapidly developed
role of ATP in photosynthesis
provides the energy to make carbohydrate molecules
which molecule would first contain 14C if the alga Chlorella was grown in the presence of light and radioactive CO2?
glycerate 3-phosphate
which technological advance enabled Calvin to perform his lollipop experiment on the light-independent reactions of photosynthesis in 1949?
methods for tracing radioactive carbon incorporated in molecules produced by the alga Chlorella
what explains that oxidative dephosphorylation in krebs cycle enables energy to be converted into a usable form?
chemical energy stored in the C6 compound is used to reduce NAD+ allowing ATP production
what is produced during the light-dependent reaction of photosynthesis?
atp
co2
what process occurs during the light-independent reactions of photosynthesis?
RuBP is carboxylated then regenerated in the Calvin cycle
during photosynthesis, what happens in the chloroplast at the lumen?
protons accumulate
in the light-dependent reactions of photosynthesis what supplies low energy electrons to photosystem II?
photolysis of water
what is energy released in a cell?
atp releases inorganic phosphate
what occurs during oxidative phosphorylation?
coupling of ATP synthesis to electron transport
