unit 3: photosynthesis(1b) Flashcards
how is light energy absorbed and what does it generate?
Light energy is absorbed by
photosynthetic pigments to generate ATP
and for photolysis
what happens to the light which is not absorbed?
it is reflected or trasmitted
what is the role of chlorophyll a in photosynthesis?
only pigment which can convert light to chemical energy, which can then be used by the plant
what regions of the spectrum does chlorophyll a absorb light?
red and blue
what do carotenoids extend?
Carotenoids extend the range of wavelengths
absorbed and pass the energy to
chlorophyll for photosynthesis.
(makes more wavelengths which can be used)
what pigments are know as ‘accessory’ pigments?
chloropyhll b and carotenoids
what does an absorption spectrum show?
the extend to which different colours/wavelengths of light are absorbed by a pigment.
what colour of light is mostly reflected in chlorophll a and b?
green
shows the rate of photosythesis carried out in different colours/wavelengths of light.
action or absorption spectra?
action
on the action spectrum what area does most photosynthesis occur in?
red and blue
dip in middle at green
Each pigment absorbs a ____________ range of
wavelengths of light.
different
when chlorophyll absrobs light energy what happens?
the electrons inside the pigment molecule become excited
what happens after the elctrons become excited?
they are tranferred through the electron transport (in membranes of grana) chain which releases energy to generate ATP by ATP synthase.
what else can this energy (h+: high energy elctrons) be used for?
photolysis: water is split into
oxygen, which is evolved, and hydrogen
ions, which are transferred to the
coenzyme NADP.
what increases the range of wavelengths of light that the plant can absorb?
having multiple photosynthetic pigments
name a limiting factor for photosynthesis.
some wavelengths of light are absorbed more than others
what coenzyme does hydrogen bind with during photolysis and where does this go to?
NADP»_space; NADPH
taken to the calvin cycle with ATP
what do granum(stack of thylakoids) contain?
the photosynthetic pigments e.g. chlorophyll
what part of the chloroplast is fluid filled containing enzymes?
stroma
where does stage 1 and 2 of photosynthesis occur?
1- thylakoids
2- stroma
stage 2 of photosynthesis is ………. and does not require ……….
results in the production of ………
carbon fixation
light
glucose
how does CO2 enter the stroma?
through diffusion
firstly what does the enzyme RuBisCO do and what does this then form?
fixes carbon dioxide by attaching it to ribulose bisphosphate (RuBP) to form 3-phosphoglycerate (3PG)
what happens to the 3PG produced?
it is phosphorylated by ATP and combined with hydrogen ions from NADPH»_space; forming glyceraldehyde-3-phosphate (G3P)
