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