(7) Cellular Respiration (E) Regulation of pathways through feedback inhibition (A) Role of ATP & Phosphorylation (B) The metabolic pathway of respiration: Glycolysis and the citric acid cycle (C) The metabolic pathway of respiration: electron transport chain & ATP synthesis (D) Substrates for Respiration

Cellular Respiration (e) State when ATP supplies increase and decrease Describe the inhibition of phosphofructokinase by ATP Describe the inhibition of phosphofructokinase by citrate Describe how the rates of glycolysis and citric acid cycle become synchronised

In what stages is ATP being made? Glycolysis Citric Acid Cycle Electron Transport Chain What would happen to the number of ATP being produced if the rate of the citric acid cycle increased? What would happen to the number of ATP being produced if the rate of Glycolysis increased? What would happen to the number of ATP being produced if the Citric Acid Cycle did not occur? What would happen to the number of ATP being produced if Glycolysis did not occur?

What do you think would happen if the body make too much ATP? When do cells make ATP? The cell conserves its resources by only producing ATP when required. ATP supply increases with increasing rates of glycolysis and the citric acid cycle, and decreases when these pathways slow down. If you wanted to inhibit (stop) glycolysis, what section would you inhibit? Does the body store ATP? What do you think would happen if the body make too much ATP?

Glycolysis (occurs with or without oxygen) Glucose ATP ADP (able to continue to other pathways) Intermediate Energy investment stage (2 ATP per glucose molecule are REQUIRED) Intermediate ATP ADP Irreversible Carried out by phosphofructokinase Intermediate 2ADP 2ATP Energy PAY-OFF stage (4 ATP per glucose molecule are PRODUCED) 2NAD 2NADH 2ADP 2ATP Pyruvate (progresses to the citric acid cycle if oxygen is available)

Inhibiting Respiration through ATP If the cell produces more ATP than it needs, the ATP inhibits the action of phosphofructokinase slowing the rate of glycolysis down.

Inhibiting Respiration through Citrate The rates of glycolysis and the citric acid cycle are synchronised by the inhibition of phosphofructokinase by citrate. If citrate accumulates, glycolysis slows down and when citrate consumption increases glycolysis increases the supply of acetyl groups to the citric acid cycle.

TASK: Sum-up Qs… What 2 substances can inhibit the action of phosphofruktokinase? ATP and citrate 2. When does the rate of glycolysis increase? When there is a increase in citrate consumption 3. When does the rate of glycolysis decrease? When there is an decrease in citrate consumption 4. How does an increase in acetyl groups from glycolysis help to increase the rate of the citric acid cycle? The acetyl groups combine with a co-enzyme A molecule and then this Acetyl coenzyme A with join with OXALOACETATE to form CITRATE!

Cellular Respiration (e) State when ATP supplies increase and decrease Describe the inhibition of phosphofructokinase by ATP Describe the inhibition of phosphofructokinase by citrate Describe how the rates of glycolysis and citric acid cycle become synchronised