Unit 6- Cell Energy- Photosynthesis & Cellular Respiration

Unit 6- Cell Energy- Photosynthesis & Cellular Respiration6b- Cellular RespirationBellworkExplain the Calvin Cycle using these words: CO2 , RuBP, PGA, ATP & NADPH, PGAL.How is it a cycle?What is the final product of the Calvin Cycle?Where does it occur?

What three factors affect the rate of photosynthesis?

Bellwork1) CO2 combines with RuBP, new molecule splits into PGA.PGA combines with ATP/NADPH to become PGAL.PGAL makes glucose, leftover PGAL becomes RuBP to start cycle again.

2) Final product= glucose! 3) Occurs in the stroma.

4) Temperature, amount of CO2, amount of sunlight.

Cellular RespirationGoal of Cellular Respiration: to convert the chemical energy in food to chemical energy stored in adenosine triphosphate (ATP)ATP can then release the energy for cellular metabolic processes, such as active transport, protein synthesis, & muscle contraction Any organic molecule can be broken down into smaller molecules & then used as a source of energy to produce ATP molecules. Occurs in both autotrophs & heterotrophs

Stages of Cellular Respiration The process is generally represented using a balanced chemical equationC6H12O6 + 6O2 6CO2 + 6H2O + energy (ATP)However, to transfer the energy stored in glucose to ATP, a cell must break down glucose slowly in a series of steps and capture the energy in stages. 2 Stages (when oxygen is present)GlycolysisAnaerobic does not require oxygenAerobic RespirationAerobic- requires oxygen

GlycolysisGlycolysis- A series of reactions catalyzed by enzymesOccurs in the cytoplasm of the cellAnaerobic- Does not require oxygen

In the process of glycolysis, a glucose molecule is broken down into pyruvic acid molecules and two ATP moleculesGlucose pyruvic acid + ATP (small amount)Many texts use pyruvic acid and pyruvate interchangeably. Pyruvic acid is a pyruvate molecule that has combined with a hydrogen ionRequires 2 ATP and produces 4so net gain of 2 ATP per glucose molecule6Aerobic Respiration If oxygen is available, the 2-stage process of aerobic respiration occurs after glycolysis. The two aerobic reactions are the Krebs Cycle (aka Citric Acid Cycle) the Electron Transport ChainOccurs in the mitochondria of the cell

Krebs Cycle (Citric Acid Cycle)The pyruvic acid, produced by glycolysis, travels to the mitochondria where it is broken down in a cycle of chemical reactions Occurs in the mitochondrial matrix- space inside mitochondriaProduces carbon dioxide, ATP, & electron carriers (NADH & FADH2)Pyruvic acid CO2 + ATP (small amount) + electron carriers

CoA- coenzyme A8Krebs Cycle

CO2 is releasedPyruvic acid from Glycolysis fuels the cycleCO2 is releasedATP is releasedElectron carriers are releasedElectron Transport ChainA series of chemical reactions in which energy is transferred to form a large number of ATP molecules Located in the inner membrane of the mitochondriaUses the electron carriers (NADH and FADH2) to pass electrons down the protein chain & slowly release energy that is used to form ATP

10Electron Transport ChainAt the end of the chain oxygen combines with hydrogen & the electrons to form water. Why is oxygen required?ATP can only be synthesized if electrons continue to move along the ETC. The last molecule in the chain must pass the electrons to a final electron acceptor. Otherwise, the process would stop.

11Checkpoint: try to fill in the blank!The steps of Cellular respiration:GlycolysisProduces what?Needs or does not need oxygen?Aerobic Respiration: Needs or does not need oxygen?What does it use in the Krebs cycle?What does it produce in the Krebs cycle?After the Krebs Cycle, the Electron Transport Chain. What is produced?Cellular RespirationGlycolysisCitric Acid Cycle (Krebs Cycle)Electron Transport Chain1 Glucose2 Pyruvic Acid2 ATP2 Pyruvic Acid CO22 ATP34 ATP NADH and FADH2 NADH and FADH2OxygenWaterActual number of ATP varies from cell to cell. Most eukaryotic cells have to actively transport NADH into the mitochondria so the max net ATP is 36; also depends on the conditions within the cell

13Cellular Respiration EquationC6H12O6 + 6O2 6CO2 + 6H2O + energyWater released from Electron Transport ChainOxygen from the atmosphereUsed in Electron Transport ChainCarbon Dioxide waste product of the Krebs cycleATP released from Glycolysis, Krebs Cycle, & Electron Transport Chain Up to 38 ATP molecules are made from the breakdown of one glucose molecule: 2 from glycolysis & up to 36 from aerobic respiration. Most of the energy released by respiration, that is not used to make ATP, is released in the form of heat. Glucose made in photosynthesis by plants or consumed by animalsUsed in Glycolysis