Bell Work! What is the Equation for photosynthesis?

Photosynthesis Ch 8.2

Light-independent reactions Photosynthesis Photosynthesis occurs in two phases. Light-dependent reactions light absorbed and converted into chemical energy (ATP and NADPH) Light-independent reactions ATP and NADPH used to make glucose

Photosynthesis Check! What are the reactants of photosynthesis? What are the products of photosynthesis?

Phase One: Light dependent reactions

Phase one: light reactions The absorption of light is the first step in photosynthesis. Chloroplasts capture light energy.

Chloroplasts Thylakoid- flattened sac like membrane Granum – Stacks of thylakoids Stroma – Fluid filled area

Electron Transport Light energy excites electrons in photosystem II Light causes a water molecule to split, releasing an electron into the electron transport system H+ released into the thylakoid space, O2 released as a waste product.

Light energy excites electrons in photosystem II and also causes a water molecule to split, releasing an electron into the electron transport system, H+ into the thylakoid space, and O2 as a waste product.

Electron Transport The excited electrons move from photosystem II to an electron-acceptor protein in the thylakoid membrane. The electron-acceptor protein transports the electrons along a series of proteins to photosystem I.

The electron-acceptor molecule transfers the electrons along a series of electron-carriers to photosystem I. The excited electrons move from photosystem II to an electron-acceptor molecule in the thylakoid membrane.

Electron Transport Photosystem I transfers the electrons to a protein called ferrodoxin. Ferrodoxin is the FINAL ELECTRON ACCEPTOR Ferrodoxin transfers the electrons to the electron carrier NADP+, forming the energy-storing molecule NADPH.

Photosystem I transfers the electrons to a protein called ferrodoxin. Ferrodoxin transfers the electrons to the electron carrier NADP+, forming the energy-storing molecule NADPH.

Chemiosmosis ATP is produced as a result of the flow of electrons down a concentration gradient the accumulated protons in the thylakoid space activate ATP synthase, forming ATP in the stroma

Light reactions Check! What molecules go into the light reactions? What molecules come out of the light reactions? In: water, light, nadp+, ADP Out: O2 NADPH, ATP

Phase Two : The Calvin cycle

Bell Work! Where do the light reactions occur?

Calvin Cycle In the Calvin cycle energy is stored in organic molecules such as glucose. Occurs in stroma of chloroplast

Calvin cycle Six CO2 molecules combine with six 5-carbon compounds to form twelve 3-carbon molecules called 3-PGA.

Calvin cycle The chemical energy stored in ATP and NADPH is transferred to the 3-PGA molecules to form high-energy molecules called G3P.

Calvin cycle Two G3P molecules leave the cycle to be used for the production of glucose and other organic compounds

Calvin cycle An enzyme called rubisco converts the remaining ten G3P molecules into 5-carbon molecules called RuBP.

Calvin cycle RuBP molecules combine with new carbon dioxide molecules to continue the cycle.

Calvin cycle check! What molecules go into the Calvin cycle? What molecules come out of the Calvin cycle? In: ATP, Co2, NADPH Out: G3P, ADP, NADP+

Cellular Respiration Ch 8.3

Overview of Cellular Respiration Section 3 Cellular Energy Cellular Respiration Overview of Cellular Respiration Organisms obtain energy in a process called cellular respiration. The equation for cellular respiration is the opposite of the equation for photosynthesis.

Cellular respiration occurs in two main parts. Section 3 Cellular Energy Cellular Respiration Cellular respiration occurs in two main parts. Glycolysis (anaerobic) Aerobic respiration (Krebs cycle and electron transport chain)

Section 3 Cellular Energy Cellular Respiration Glycolysis Glucose is broken down in the cytoplasm through the process of glycolysis. Two molecules of ATP and two molecules of NADH are formed for each molecule of glucose that is broken down.

Krebs Cycle Cellular Respiration Section 3 Cellular Energy Cellular Respiration Krebs Cycle Glycolysis has a net result of two ATP and two pyruvate. Most of the energy from the glucose is still contained in the pyruvate. The series of reactions in which pyruvate is broken down into carbon dioxide is called the Krebs cycle.

Section 3 Cellular Energy Cellular Respiration The net yield from the Krebs cycle is six CO2 molecules, two ATP, eight NADH, and two FADH2.

Final step in the breakdown of glucose Section 3 Cellular Energy Cellular Respiration Electron Transport Final step in the breakdown of glucose Point at which ATP is produced Produces 24 ATP

Anaerobic Respiration Section 3 Cellular Energy Cellular Respiration Anaerobic Respiration The anaerobic pathway that follows glycolysis Two main types Lactic acid fermentation Alcohol fermentation