1. Using Glucose

2. Chemical Energy Chemical Energy is energy that is found in chemical substances The energy is stored in the links (bonds) between the atoms When the bonds are broken, the energy is released

3. Glucose The bonds between the atoms are represented by the red and black lines Chemical energy in glucose cannot be used directly by the cells It needs to be converted to another form of chemical energy called ATP

4. ATP – Adenosine Tri-phosphate ATP is made up of Adenosine, ribose and 3 phosphates The bonds between the phosphate groups are very high in energy When one of the phosphate bonds is broken, energy is released that cells can use directly Adenosine Ribose 3 Phosphates This energy can be used for a range of cellular activities: To power other chemical reactions Growth Tissue repair Movement Reproduction Active Transport Secretion

5. Using ATP When ATP is used for energy by cells, one of the phosphates is broken off, forming ADP (Adenosine Di-phosphate) ~~ Adenosine PPP ~~~ PP P Energy for cell ATP ADP H2OH2O

6. What happens to ADP? ~~ Adenosine PPP ~~~ PP P Energy for cell ATP ADP In order to get the energy required to turn ADP back into ATP: ADP + Pi  ATP the reaction is coupled with another chemical reaction. To convert ADP back to ATP, energy is required This is called cellular respiration

7. Reactants & Products Reactants: O2O2 C 6 H 12 O 6 Products: H2OH2O CO 2 LookFamiliar?How? ADP ATP

8. Elements Hydrogen Carbon Oxygen

9. Remember Photosynthesis? 6H 2 O + 6CO 2  C 6 H 12 O 6 + 6O 2 If the reaction was reversed, would energy still need to be put in? Chlorophyll Sunlight Energy is put in

10. The Chemical Reaction Chlorophyll Sunlight 6O 2 + C 6 H 12 O 6  6CO 2 + 6H 2 O Energy is released

11. The Chemical Reaction Chlorophyll Sunlight 36-38 ADP + Pi36-38 ATP 6O 2 + C 6 H 12 O 6  6CO 2 + 6H 2 O Oxygen + Glucose  Carbon dioxide + Water This reaction releases chemical energy And the energy given off is used to convert ADP back to ATP

12. Aerobic Cellular Respiration The formula for the reaction shown is a simplified version of what really happens In reality, the reaction occurs with the help of many enzymes in many steps The main phases of the reaction are: Glycolysis Krebs cycle Electron Transport

13. Glycolysis Glycolysis involves the splitting of the glucose molecule into 2 pyruvate molecules This releases energy The energy is used to create ATP and another energy molecule which can be used to create ATP, called NADH 2 NADH

14. Kreb’s Cycle (Citric Acid Cycle) The 2 pyruvate molecules then enter the mitochondrion where they undergo further chemical reactions to form more ATP, NADH and CO 2 This occurs with the help of other molecules such as coenzyme A In addition, another energy molecule called FADH 2 is produced

15. Electron Transport In the final stage of aerobic respiration the NADH and FADH 2 are broken down into NAD and FAD The energy released from this is used to create more ATP This stage of respiration requires O 2 and also occurs in the mitochondrion It is in this stage that water is produced as a waste product Each NADH is able to yield 3 ATP whilst each FADH 2 can yield either 2 or 3 ATP

16. This means that oxygen is involved

17. In summary… PhaseLocationReactantsProducts GlycolysisCytoplasm1 Glucose molecule 2 ATP 2 NADH 2 Pyruvate Kreb’s Cycle Inside mitochondrion 2 Pyruvate molecules (from glycolysis) 2 ATP 8 NADH 2 FADH 2 6 CO 2 Electron Transport Mitochondrial membranes 6 O 2 10 NADH 2 FADH 2 32-34 ATP 6 H 2 O Overall1 Glucose 6 O 2 36-38 ATP 6 CO 2 6 H 2 O

18. Aerobic Vs. Anaerobic The type of cellular respiration that we have been talking about so far is called ‘aerobic’ meaning that it happens in the presence of oxygen Another type of cellular respiration is called ‘anaerobic’ meaning that it happens without oxygen

19. Anaerobic Anaerobic respiration: produces an additional waste product which differs in different types of living things is not as efficient as aerobic respiration This is because it does not happen in the mitochondria but in the cytoplasm of the cell In fact, anaerobic respiration only involves the first phase of cellular respiration, glycolysis

20. Anaerobic respiration As you may recall, glycolysis occurs in the cytoplasm and only produces 2 ATP It occurs during times when the cell is unable to obtain O 2 (eg. Prolonged physical activity) However, in this case, the pyruvate does not enter the Kreb’s cycle but converted to a waste product The waste product varies according to the type of cell

21. 2 ADP + Pi2 ATP C 6 H 12 O 6  6CO 2 + 6H 2 O + waste Waste products vary: In plants = pyruvic acid In animals = lactic acid In yeast = alcohol In bacteria = some alcohol, some lactic acid The Chemical Reaction

22. Aerobic Vs. Anaerobic AerobicAnaerobic Location in cell MitochondrionCytoplasm Use of oxygen YesNo No. of ATP produced 36-382 WasteCO 2 + WaterCO 2 + Water + additional waste Reaction 6O 2 + C 6 H 12 O 6  6CO 2 + 6H 2 O + 36 ATP C 6 H 12 O 6  6CO 2 + 6H 2 O + 2ATP + waste

23. Aerobic Vs. Anaerobic Type of Living Thing Waste PlantPyruvic acid AnimalLactic acid (think of athletes) YeastAlcohol (think of beer/wine)