Energy transfers in and between organisms Flashcards
Photosystems
structures that photosynthetic pigments are arranged in
where are photosystems found
thylakoid membranes
accessory pigments
absorb the wavelengths of light that are not easily absorbed by chlorophyll and are not directly involved in the light dependent reactions. They channel more captured light energy to chlorophyll so more electrons can be excited.
where is p680 chlorophyll a
photosystem 2
where is p700 chlorophyll b
photosystem 1
primary pigment centre
where chlorophyll a is at the base of the photosystem
p700 absorption peak
700nm
p680 absorption peak
680nm
how do photosystems work
The energy from absorbing light is passed from 1 accessory pigment to another
until it reaches the primary pigment. The energy is then used to excite pairs of electrons in the reaction centre
pigment. The electrons move up to a higher energy level, ready to be used in the
light dependent reactions
why is it useful for plants to have different pigments
so more wavelengths of light can be absorbed
Thylakoid adaptations for photosynthesis
contain photosynthetic pigments, large SA to increase absorption, contains ATP synthase to make ATP
Oxidation
loss of electrons, energy released
Reduction
gain of electrons, energy taken in
where does the light dependant reaction of photosynthesis take place
thylakoid membranes
light independant reaction
-CO2 combines with RUBP
-produces 2, 3GPs
-GP is reduced to form TP
-requires reduced NADP and energy from ATP
-TP is converted to glucose
light dependant reaction
-light energy breaks down water forming H+, e- and oxygen
-forms H+ gradient
-electrons travel through electron transport chain
-reduced NADP produced (NADP+H+)
-ATP produced by phospholyration
phospholyration equation
ADP + Pi = ATP
Photolysis equation
H2O = H+ + e- + O2
electron carriers
proteins which transfer electrons
Glycolysis
~Glucose phospholyrated to hexose biphosphate
~hexose biphosphate converted to 2 Triose Phosphates
~The TPs are oxidised to form pyruvate
~produces NADH
Link reaction
~Pyruvate enters mitochondria
~Pyruvate combines with coenzyme a to form acetylcoenzyme a
~CO2 and Hydrogen are removed from pyruvate
Krebs cycle
~acetylcoenzyme a combines with oxaloacetate to form a 6C compound
~CO2 released, hydrogen reduces NAD and FAD to NADH and FADH
~oxaloacetate regenerates to be used again
~2 ATP molecules produced
Electron Transport Chain (respiration)
~NADH and FADH oxidised to NAD and FAD
~ H removed splits into proton and e-
~electrons pass through electron carriers, releasing energy which is used to pump H+ ions from matrix to intermembrane space through ATPase
~converts ADP to ATP
~water is formed by combining of proton, e- and O2
What stages happen in anaerobic respiration
Just Glycolysis
Nitrogen cycle
~ammonification- nitrogen containing compounds broken down by saprobionts to produce ammonia
~nitrification- ammonia converted to nitrite then nitrate ions
~denitrification- bacteria convert nitrate ions to nitrogen gas
~nitrogen fixation- nitrogen gas converted to nitrogen containing compounds
