Photosynthesis and Cellular Respiration

• Photosynthesis

  • Process used by plants to make FOOD (glucose)

  • Two processes take place in two locations

    • Light Dependant Reactions

      • Happens in membranes of Thylakoids

      • Turns NADP+, ADP, and H2O into NADPH, ATP, and O2 (released as waste)

        • Uses energy from sunlight to load molecules with electrons

        • Any ATP made is used in the next step

      • Actively pumps H+ into the lumen

      •  H+ then enters cell through transport proteins to turn ADP into ATP

      • Composed of photosystems I, II and chemiosmosis

• Calvin Cycle

  • Happens in the stroma of chloroplasts

  • Turns CO2, NADPH, and ATP into into Glucose, NADP+, and ADP

    • These get used in cellular respiration and light dependant reactions

    • FIXES ATMOSPHERIC (INORGANIC) CARBON INTO ORGANIC CARBON

• You can run experiments to determine which reaction is defective 

  • Light dependant= test for O2 absorption

  • Calvin Cycle= Test CO2 absorption

• Cellular respiration

  • ALL LIVING THINGS DO CELLULAR RESPIRATION

  • Happens in mitochondria of eukaryotes and cytoplasm of eukaryotes

  • ALL respirations requires pyruvate

  • Several steps

    • Glycolysis

      • Happens of the cytoplasm of ALL living things

        • Evidence of common ancestry

      • Glucose is oxidized into 2 pyruvate molecules

      • 2 NAD+ are reduced into 2 NADH

        • These electrons are carried into later processes

      • Requires 2 ATP but makes 4 ATP

• Linking Step

  • Beginning of aerobic respiration

  • Pyruvate is converted into Acetyl-coA

  • Acetyl-coA is transported INTO the mitochondria

• Citric Acid/ Krebs Cycle

  • Acetyl-CoA goes through a series of exergonic chemical reaction that reduce NAD+ to NADH and FADH to FADH2

  • Happens twice per glucose molecule

• Electron Transport Chain (ETC)

  • Occurs IN the inner mitochondrial membrane

  • NADH and FADH2 are oxidized, releasing electrons and energy

    • NAD+ and FAD+ are recycled back into the environment

  • Electrons move through the ETC, losing energy until they combine with O2 and H+ ions to form water as a waste product

  •  Energy released is used to maintain an H+ ion gradient across the inner mitochondrial membrane

  • Oxidative Phosphorylation

    • Works with the ETC

    • H+ ions diffuse through ATP Synthase (an enzyme) from the matrix to the intermembrane space

    • Energy from this  diffusion is captured and used by ATP Synthase to phosphorylate ADP into ATP

    • Generates 32-34 ATP

• Types of Respiration

  • Anaerobic vs. Aerobic

    • Anaerobic 

      • REQUIRES NO OXYGEN

      • Stops at glycolysis

      • Makes lactic acid or alcohol as byproducts

      • Faster but makes less energy

    • Aerobic

      • REQUIRES OXYGEN

      • Goes through all parts of respiration

• Oxidative Efficiency

  • Energy that is not captured from oxidation of NADH during the ETC is given off as heat.

  • Homeothermic organisms will decouple the ETC and Oxidative phosphorylation to generate more heat and regulate body temperature