How Cells Release Stored Energy

1. How Cells Release Stored Energy • “Killer” Bees- Aggressive descendents of African honeybees that were imported to Brazil in the 1950s • Africanized bee’s muscle cells have • enlarged __________________ ATP Is ____________ Energy Source Chapter 7 • Photosynthesizers get energy from the ___ • Animals get energy second- or third-hand from ____ or other ____________ • Regardless, the energy is converted to the chemical bond energy of ____

2. Making ATP • All organisms- breakdown of carbohydrates, fats, and protein • Plants only - during photosynthesis Two pathways Aerobic Anaerobic O2 required? ___ ___ __________ _________ _________ Process Location _________, __________ ____________

3. Aerobic Respiration C6H1206 + 6O2 6CO2 + 6H20 ________ ______ ______ ______ ________ Glucose (C6H12O6) a simple sugar • 2 Pyruvate(three carbons) 6CO2

4. 2 ADP 2 ____ 2 ADP 2 _____ 2. _______ 1. ________ Glucose 2 Pyruvate 6 CO2 2 NAD+ 2 ______ 8 NAD+ 8 NADH 2 FAD+ 2 FADH2 3. _______ ________ 6 ADP _______ 28 ADP _______ Aerobic Respiration Add up total ATP generated : 2+2+6+28=____

5. Overview of Aerobic Respiration _________ CYTOPLASM glucose ATP 1. ________ (In cytoplasm) GLYCOLYSIS energy input to start reactions (2 ATP net) e- + H+ 2 pyruvate 2 NADH MITOCHONDRION ___________ e- + H+ 2 CO2 2 NADH e- + H+ 2. ____________ (in mitochondrial matrix) 4 CO2 8 NADH KREBS CYCLE e- + H+ 2 ATP 2 FADH2 e- ELECTRON TRANSPORT PHOSPHORYLATION 3. ______________ (In inner mitochondrial membrane) 32 ATP H+ water e- +oxygen TYPICAL ENERGY YIELD: 36 ATP End result: ATP is generated

6. 1. Glycolysis • Divided into two phases: • an _____________ phase • 2 ATP used • an _____________ phase. • 4 ATP + 2 NADH produced Each of _____ steps in glycolysis is catalyzed by a specific _______. Net yield in glycolysis = __ATP + __NADH

7. The Role of Coenzymes • ____ and ______ accept electrons and hydrogen …then deliver them to the ______ _________ system

8. 2 ADP 2 ATP 2 ADP 2 ATP Glucose 2 Pyruvate 6 CO2 2 NAD+ 2 NADH 8 NAD+ 8 NADH 2 FAD+ 2 FADH2 2. Krebs cycle ________ ______ • If __________ is present, pyruvate enters the _____________ where enzymes of the Krebs cycle complete the _________ of the organic fuel to carbon dioxide.

9. 2 ADP 2 ATP 2 ADP 2 ATP Glucose 2 Pyruvate 6 CO2 These are generated by____________________________ What is substrate level phosphorylation? Enzyme • An ______ transfers a phosphate group from an organic molecule (the substrate) to ____, forming ____-.

10. 2. Krebs cycle • The Krebs cycle consists of ____ steps. Named after Hans Kreb – 1930s • Each cycle produces • one ATP by ________________ ______________ • three _________ • and one _______ Fig. 9.11

11. 2 carbon atoms enter • The conversion of pyruvate and the Krebs cycle produces large quantities of _____________. 2 carbon atoms released as CO2 Note the Krebs cycle is never depleted of ______: 2 in, 2 out Fig. 9.12

12. ____________ ___________ 2 NAD+ ___________ 8 NAD+ 8 NADH 2 FAD+ 2 FADH2 Electron transport 6 ADP __________ 28 ADP __________ 3. Electron transport Coenzymes deliver electrons to electron transport systems Add up total ATP generated : 2+2+6+28=_____

13. Electron transport glucose GLYCOLYSIS pyruvate KREBS CYCLE ELECTRON TRANSPORT PHOSPHORYLATION Mitochondria in-text, p. 116

14. 4 important facts: • Coenzymes deliver _________ to ET chain • H+ ions are delivered to ______ compartment • H+ _________ is created • ___is final _____________

15. Making ATP: __________________ Model • H+ ions going back to _______ compartment generates _______ ATP INNER COMPARTMENT ADP+Pi

16. Overview of respiration 1 Pyruvate from cytoplasm enters inner mitochondrial compartment. OUTER COMPARTMENT 4 As electrons move through the transport system, H+ is pumped to outer compartment. NADH 3 NADH and FADH2 give up electrons and H+ to membrane-bound electron transport systems. acetyl-CoA NADH Krebs Cycle NADH ATP ATP 5 Oxygen accepts electrons, joins with H+ to form water. ATP 2 Krebs cycle and preparatory steps: NAD+ and FADH2 accept electrons and hydrogen stripped from the pyruvate. ATP forms. Carbon dioxide forms. ATP free oxygen ADP + Pi INNER COMPARTMENT 6 Following its gradients, H+ flows back into inner compartment, through ATP synthases. The flow drives ATP formation. Fig. 7.5b, p. 114

17. How efficient is respiration in generating ATP? • Complete oxidation of glucose = ____ kcal/mole. • Formation of each ATP requires = _____ kcal/mole. • Efficiency of respiration is • __ kcal/mole x -_ ATP/glucose = __%. 686 kcal/mole glucose • The other approximately 60% is lost as ______. • Cellular respiration is remarkably ________ in energy conversion.

18. ____________enables some cells to produce ATP without the use of_________ Fig. 9.17a • Glycolysis generates ______ whether oxygen is present (aerobic) or not (anaerobic). Problem- Fermentation (anaerobic catabolism) still requires NAD+ to accept electrons. Ethanol Solution-In __________________, NAD+ comes from the conversion of pyruvate to ______________

19. A second solution to the NAD+ problem: • ___________________________ • ( pyruvate is reduced directly by NADH to form___________) • Muscle cells switch from ______ respiration to lactic acid f____________ to generate ATP when -____ is scarce. • The waste product, lactate causes muscle fatigue but ultimately it is converted back to pyruvate in the liver. Lactate

20. A third solution to the NAD+ problem • Certain anaerobic bacteria solve NAD+ problem by using compounds from environment (such as nitrate), NOT oxygen • ATP yield is low

21. Compare respiration and fermentation Similarities • Both use glycolysis to generate __________ • Both use NAD+ as an _________________. Respiration Fermentation Type Aerobic Anaerobic NAD+ regeneration ___ Organic molecules Energy yield ___ATP ___ ATP

22. At a cellular level, human ______ cells can behave as facultative anaerobes, but __________ cells cannot. • For facultative ________________, pyruvate is a fork in the metabolic road that leads to two alternative routes. Ethanol or lactate Fig. 9.18

23. 7. How do other________________ fit into glycolysis and the Kreb cycle?? Answer- _________,______________________________ can all enter the pathway. • _____ are degraded to amino acids, then deaminated (nitrogen secreted as urea, ammonia) • ________ are broken down to glucose. • ______ must be digested to glycerol and fatty acids.

24. If glucose is the key to ATP production, then how do we store glucose?? Answer- ___________ (in animals) _______ and _______ (in plants) Animals • Glucose absorbed by blood • Pancreas releases insulin • Insulin stimulates glucose uptake by cells • Cells convert glucose to __________________ • This traps glucose in cytoplasm where it can be used for glycolysis • If ATP _____, glucose stored as _________ in muscle and liver

25. Using Glycogen • When blood glucose low, pancreas releases _____________ • Glucagon stimulates liver cells to convert glycogen back to glucose and to release it to the blood • (Muscle cells do not _____________ their stored glycogen)

26. Energy Reserves • Glycogen- ___% • Proteins- ___ % • Fat – ____%

27. Linking photosynthesis and respiration sunlight energy PHOTOSYNTHESIS water + carbondioxide sugarmolecules oxygen AEROBICRESPIRATION in-text, p. 122