photosynthesis Flashcards
name 2 accessory pigments
chlorophyll b -broaden the light spectrum
carotenoids- absorb excessive light that would damage chlorophyll
what is the difference between chlorophyll a and b
differ in their absorbance and structure
a- CH3
b -CHO
both sensitive to long waves and to colour
most sensitive in the early mornings and late at day
what is a bi product of photosynthesis
oxygen
what is an afterglow
fluorescence, when excited el fall back to ground state and photons are given off
tell about Photosystem 2
- function first
- absorbs light at 680nm
- reaction centre called P680
tell about Photosystem 1
- reacts second
- absorbs light at 700
- reaction centre P700
how is water split
split in P2 at lower energy point, catalysed by manganese clusters ( catalytic core)
what is an Z scheme
when water splits, electrons are transferred to plastoquinol, then to cytochrome B6-F complex and to plastocyanin ( copper containing)
what enzyme is used in Ph1 and what is the role of it
ferredoxin
ferredoxin- NADP and reductase catalyse the transfer of el to NADP to produce NADPH ( plant store energy )
what is NADPH used for?
released into chloroplast stroma to generate glyceride 3 phosphate, fatty acids and protein
what is an alternative way to use electrons
ATP synthesis in thylakoid membrane uses el gradient to generate ATP
what is an Calvin cycle
is a chemically unfavourable reaction, driven by NADPH and ATP
how many CO2 is needed to produce 1 mol of glycerol aldehyde 3 phosphate
3 CO2 is needed
+ 9 ATP and 6 NADPH
what is the role of calvin cycle
to put the excess energy in storable form
what is cycling ( mitochondria)
during night mitochondria elongates, uses sorted glyceridealdehsyde 3 p
during day time - it shrinks
