Photosynthesis & respiration

• What is a photoautotroph?

  Organism can make its own food using light energy. Process of photosynthesis same in all photoautotrophs, suggesting they all evolved from a common ancestor.
• What is the equation for photosynthesis?

  6CO2 + 6H2O + energy = C6H12O6 + 602
• What does anaerobic respiration produce?

  In plants & yeast : ethanol, carbon dioxide & releases energy. In humans: lactate produced & releases energy.
• What is the equation for aerobic respiration?

  C6H12O6 + 6O2 ---> 6CO2 + 6H2O + energy
• What are the properties of ATP?

  Stores & releases small amount of energy so none is wasted as heat, small soluble molecule so easily transported, easily broken down, quickly remade, can't pass out cell & can make other molecules more reactive (phosphorylation).
• What is the compensation point for light intensity?

  Particular level of light intensity at which rate of photosynthesis exactly matches rate of respiration.
• How can you work out the compensation point for a plant?

  Measure rate at which oxygen is produced & used at different light intensities. Compensation point is light intensity at which oxygen is being used as quickly as it's produced. Rate of CO2 production can also be measured.
• What are the 2 stages of photosynthesis?

  Light-dependent reaction and Calvin cycle (light-independent reaction)
• What is chemiosmosis?

  Diffusion of protons/hydrogen ions down electrochemical gradient across ATP synthase to generate ATP.
• Where are photosynthetic pigments found?

  Thylakoid membranes (chloroplast) attached to proteins. Pigments are A, B & carotene. The protein & pigment are called a photosystem. 2 photosystems used by plants to absorb light are PS1 (700nm wavelength) & PSII (680nm).
• What happens in PSII?

  Light energy absorbed by PSII. Light energy excites electrons in chlorophyll. Electrons move to a higher energy level. These high energy electrons move along the electron transport chain (made of proteins) to PSI.
• What is light energy used for in the light-dependent reaction?

  Making ATP from ADP & Pi (photophosphorylation), making reduced NADP & splitting water into protons, electrons & oxygen (photolysis).
• What does non-cyclic photophosphorylation produce?

  ATP, reduced NADP & oxygen.
• Where does glycolysis take place?

  Cytoplasm- glucose too big for mitochondria.
• What are the stages of glycolysis?

  Glucose -> hexose bisphosphate -> triose phosphate (x2) -> pyruvate (x2).
• What are the products of glycolysis?

  2 reduced NAD, 4 ATP (net gain of 2 ATP) & 2 pyruvate. Reduced NAD enters cristae for oxidative phosphorylation. Pyruvate enters link + Kreb's cycle in matrix.