Section 5 Revision

• temperature • co2 concentration • light intensity

• Stacks of thylakoid membranes called grana provide a large surface area for chlorophyll to attach to • Network of proteins in grana hold chlorophyll in specific place to maximise the absorption of light • Grana membrane has ATP synthase allowing ATP to be synthesised as well as being selectively permeable allowing the establishment of the proton gradient • Chloroplasts contain DNA and ribosomes allowing them to synthesise proteins needed in the LDR

• Chlorophyll absorbs light and looses 2 electrons, becoming oxidised- photoionisation. The electrons are passed along the electron carriers in a series of redox reactions which releases energy. • This energy is used by electron carriers to pump H+ ions across the thylakoid membrane into the thylakoid space creating an electrochemical gradient across the thylakoid membrane • Water absorbs light and undergoes photolysis splitting into O2, 2H+ and 2 electrons, these electrons replace those lost by chlorophyll. O2 either simply diffuses out the stomata or is used in respiration. H+ ions contribute to the high concentration in the thylakoid space. • H+ ions diffuse down the electrochemical gradient through ATP synthase into the stroma. This drives the synthesis of ATP from ADP+ Pi via phosphorylation by the chemiosmosis theory • NADP accepts the H+ and electrons from the last electron carriers and becomes reduced. The ATP and reduced NADP is then used In the light independent reaction.

• Carbon dioxide joins with RuBP to form two GP molecules and this is catalysed by the rubisco enzyme • 2GP is reduced to two triose phosphate using reduced NADP and the energy from the hydrolysis of ATP both supplied from the light dependent reaction. • Some triose phosphate molecules is converted to useful organic substances such as glucose • Most triose phosphate molecules are used to regenerate RuBP using ATP (specifically the Pi)

• Fluid in stroma contains high concentrations of all necessary enzymes for the LIDR • Stroma surrounds grana so the products of the LDR can readily diffuse into the stroma to be used in the LIDR (reduced NaDP and ATP) • Contains DNA and ribosomes so necessary proteins in the LIDR can be easily made

On the thylakoid membrane

In the stroma

• Air spaces allow fast diffusion of CO2 to cells • Lots of stomata so a large surface area for CO2 to enter and O2 to leave • Xylem provides water for the light dependent reaction • Lots of chloroplasts in the palisade and spongey mesophyll layer

• Inner and outer membrane • Thylakoid • Granum • Circular DNA • Starch granule • 70s ribosomes

• measuring pH can tell us the difference in rate between photosynthesis and respiration . pH stays the same when rate of photosynthesis = rate of respiration . ph increases when rate of photosynthesis > rate of respiration . pH decreases when rate of photosynthesis < rate of respiration

The wavelengths of light that the plant pigments absorb

The rate of photosynthesis at each wavelength of light

It means a multitude of different wavelengths can be absorbed

• Rate of O2 production • Using isolated chloroplasts and examining the rate of colour change in the redox indicator (DCPIP)

DCPIP accepts the electrons in place of NADP at the end of the electron carrier transfer chain in the LDR

• Draw a line of origin in pencil on the chromatography paper • Load the mixture onto the pencil line and place several spots allowing drying in between • Put in boiling tube with solvent in and place a bung on top • Ensure that the solvent doesn’t submerge the paper line • Wait until the solvent is almost near the top of the paper • Remove and draw on solvent front immediately • Calculate the rF values and compare with those in the data book to identity the substances in the mixture

rF= distance moved by the spot / distance moved by the solvent

• Short term energy molecule- provides small manageable amounts of energy for active transport • Phosphorylation of molecules to increase reactivity

Only one bond needs to break to release energy which makes it immediate and can be easily reformed by ATP synthase

• Double membrane • Circular DNA • 70s ribosomes • Cristae • Matrix

• Glycolysis - cytoplasm • Link reaction - matrix of the mitochondria • Krebs cycle - matrix of the mitochondria • Electron transfer chain - uses proteins in the cristae of mitochondria

• Glucose is phosphorylated to make it more reactive using 2 ATP • Glucose phosphate splits into 2 triose phosphate molecules • Each triose phosphate is oxidised to pyruvate using NAD which is reduced to reduced NAD • 4 ATP are produced and there is a net gain of 2 ATP in glycolysis

• Both pyruvates produced in glycolysis are transported into the mitochondrian by active transport • Pyruvate is oxidised and decarboxylated to produce acetate • Carbon is lost as carbon dioxide and NAD is reduced to reduced NAD • Acetate combines with coenzyme A to form acetyl coenzyme A

• Acetyl coenzyme A reacts with a 4C molecule releasing coenzyme A and producing a 6C molecule • The 6C molecule is decarboxylated releasing CO2 and oxidised, reducing NAD to reduced NAD to form a 5c molecule • The 5c molecule is decarboxylated releasing CO2 and oxidised, reducing NAD to reduced NAD to form a 5c molecule • ATP is formed via substrate level phosphorylation • A 4C molecule is oxidised reducing FAD to reduced FAD • Another 4C molecule is oxidised, reducing NAD and regenerating the original 4C molecule