Photosynthesis

process in plants of breaking down carbon dioxide and oxygen into glucose with he assistance of sunlight

main type of chlorophyll that all plants have

• absorb energy that chlorophyll "a" does not absorb
• such as chlorophyll b, c, d, e 
• carotenoids (blood orange)

• to absorb different waves of energy
• different pigments absorb different, specific kinds of energy

change colour because the light is received by the leaf at a different angle, therefore different wavelengths/colours are absorbed by the leaf

• trees talking using hormones
• why all trees' leaves change colour at same time

organelle

pigment/colour

• dead cells/tissue
• transports water

• living cells
• transports sugars

exchange gases

• prevent water loss
• Cuticle is waxy, wax is an oil, water cannot escape past this oily waxy layer of the leaf

contain chloroplasts

• system of interconnected flattened membrane sacs
• stack on top of each other, forming grana (multiple thylakoids stacked)

structural support

• occurs in thylakoid, stroma
• thylakoid: light dependent reactions, has pigment, traps light, so light is used
• stroma: light independent reactions, does not need any light

splits H2O, CO2, to make glucose (energy)

• holds electrons, gives electrons to something else
• made of an NADP, and an H
• NADP is positively charged, therefore bonds with two e- to balance out

• 1. capture solar energy and transfer it to e-
• 2. use captured solar energy to make ATP; transfer high energy e- to NADP+: NADPH is then used as a high energy e- carrier
• 3.

cellular respiration

• occurs during either day or night
• a.k.a. Calvin cycle
• carbon fixation occurs: incorporation of CO2 into organic compounds such as glucose
• occurs in stroma or chloroplast
• uses ATP and NADPH from light dependent reactions

gel-like fluid inside of chloroplast

• occurs in thylakoid membranes
• cluster of chlorophyll and other pigments 
• photosystem 1 uses chlorophyll "a"
• photosystem 2 uses a slightly different form of chlorophyll "a"
• photosystems operate so that a wide range of wavelengths can be used for photosynthesis
• photosystem 2 occurs first, then photosystem 1 occurs second
• 2 energized e- are removed from photosystem 2 from chlorophyll
• e- enters an electron transfer chain

• areas where light is being captured
• photosystem 2 makes NADPH
• photosystem 1 makes ATP

• any time when an electron is moved
• ANY
• A N Y
• literally any time

• hot potato, basically of electrons
• ATP is made because of the energy release through the chain

• occurs in thylakoid lumen
• literally "light cut"
• solar energy absorbed by chlorophyll is used to split water into H, e-, O2
• e- travels to photosystem 2
• O exits thru stomata or is used to make H2O
• H will be used later to reduce ADP

• a) e-, excited by light at photosystem 2, are passed along an ETC
• e- releases energy at every step
• b) energy from e- is used to pull H+ ions across membrane into lumen
• e- have lost most of their energy
• H+ ion concentration builds up and so does a positive charge 
• c) e- are transferred from ETC to photosystem 1
• d) e- are transferred to NADPH

• diffusion based on concentration of positive Hydrogen ions (high to low)
• electrical gradient results
• H+ ions rush through ATP synthase complex
• in doing so, H+ ions generate energy
• this energy is used to create ATP
• this energy in H+ ions comes from the sun originally
• ATP synthase complex is in the thylakoid membrane

• happens in stroma
• Calvin-Benson cycle and carbon fixation
• carbon fixation = turning CO2 into glucose
• upon entering Calvin cycle, carbon is reduced
• direct product of Calvin cycle is G3P/PGAL, precursor to glucose

• C, O atoms provided by CO2
• H atoms provided by photolysis of H2O
• 3 ATP, 2 NADPH are used per each CO2 that enters the Calvin cycle
• the building of one glucose molecule requires 18 ATPs, 12 NADPHs

• 1. CO2 fixation, reduction
• 2. PGAL/G3P molecules produced
• 3. regeneration of RUBP
• each stage requires enzymes to occur
• RUBP + CO2 -> unstable 6 - C molecule
• 6 - C molecule breaks down into two 3 - C molecules (PGA)

• RUBP (ribulose biphosphate) 5 carbon molecules long, attaches to CO2
• enzyme for this reaction is RUBP carboxylase

• each 3 PGA molecule gets reduced; ATP and NADPH provide this step
• 3 C PGA is reduced to form PGAL and water

• direct product - PGAL
• glucose: six revolutions of Calvin cycle required for one molecule of glucose
• 6 H2O
• (ADP, P, NADP+, H+) - products of photosynthesis

space inside of thylakoid itself

O2