1. Do now Pick up 10 alaska peas
Put in a plastic ziplock bag with your name on it
HW: Germinate them :)
Bring them in next class for our lab

2. Cellular Respiration
2.8, 8.2

3. 2.8 Cellular Respiration SL
Understanding (Statement objectives)
Define cell respiration.
Cell respiration is the controlled release of energy from organic compounds to produce ATP.
ATP from cell respiration is immediately available as a source of energy in the
cell.
Explain anaerobic cell respiration.
Anaerobic cell respiration gives a small yield of ATP from glucose.
Explain aerobic cell respiration- include the link reaction, the Krebs cycle, the role of NADH+ H+, the electron transport chain, and the role of oxygen.
Aerobic cell respiration requires oxygen and gives a large yield of ATP from glucose.
Applications
Explain the use of anaerobic cell respiration in yeasts to produce ethanol and carbon dioxide in baking.
Details of the metabolic pathways of cell respiration are not needed but the substrates and final waste products should be known.
Describe lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions.
Nature of science
Assess the ethics of scientific research—the use of invertebrates in respirometer experiments has ethical implications.
Skills
Analyze results from experiments involving measurement of respiration rates in germinating seeds or invertebrates using a respirometer.
There are many simple respirometers which could be used. Students are expected to know that an alkali is used to absorb CO2, so reductions in volume are due to oxygen use. Temperature should be kept constant to avoid volume changes due to temperature fluctuations.
Outline the process of glycolysis, including phosphorylation, lysis, oxidation, and ATP formation (in this order).
Explain the relationship between the structure of the mitochondrion and its function.

4. 8.2 Cellular Respiration HL
Understanding
Cell respiration involves the oxidation and reduction of electron carriers.
Phosphorylation of molecules makes them less stable.
In glycolysis, glucose is converted to pyruvate in the cytoplasm.
Glycolysis gives a small net gain of ATP without the use of oxygen.
In aerobic cell respiration pyruvate is decarboxylated and oxidized, and converted into acetyl compound and attached to coenzyme A to form acetyl coenzyme A in the link reaction.
In the Krebs cycle, the oxidation of acetyl groups is coupled to the reduction of hydrogen carriers, liberating carbon dioxide.
The names of the intermediate compounds in glycolysis and the Krebs cycle are not required.
Energy released by oxidation reactions is carried to the cristae of the mitochondria by reduced NAD and FAD.
Transfer of electrons between carriers in the electron transport chain in the membrane of the cristae is coupled to proton pumping.
In chemiosmosis protons diffuse through ATP synthase to generate ATP.
Oxygen is needed to bind with the free protons to maintain the hydrogen gradient, resulting in the formation of water.
The structure of the mitochondrion is adapted to the function it performs.
Applications
Explain how electron tomography is used to produce images of active mitochondria.
Nature of science
Paradigm shift—Describe the chemiosmotic theory that led to a paradigm shift in the field of bioenergetics.
Skills
Analyze diagrams of the pathways of aerobic respiration to deduce where decarboxylation and oxidation reactions occur.
Annotate a diagram of a mitochondrion to indicate the adaptations to its function.

5. Cellular Respiration
Cell respiration is the controlled release of energy from organic compounds to produce ATP

6. Cellular Respiration Catabolic, energy yielding pathway
Breaks down energy rich molecules, such as glucose
releasing energy for the synthesis of ATP
Aerobic respiration requires oxygen
Forms of respiration that do not require oxygen are anaerobic
more on this later

7. Energy as A Result of Cell Resp
Aerobic respiration has a large yield of ATP
This is immediately available as a source of energy within the cell
What is this energy used for?

8. Before We Get Started: Redox
Oxidation
Reduction
Electrons
Lost
Gained
Energy H+
Oxygen

9. Remembering Redox L E O goes G E R o s i n g l e c t r o n s x i d a tu c t i o n

10. Electron carriers

11. Electron carriers
electron carriers

12. Aerobic Respiration Summarized

13. Glycolysis Occurs in the cytoplasm “Sugar splitting”
1 glucose (6C sugar) pyruvate (3C acid)
This step of respiration is anaerobic

14. Glycolysis
Phosphorylation: 2 ATP is used to add phosphate groups to each end. Phosphorylation makes molecules less stable.
Lysis: Phosphorylated sugar splits into 2 3C sugars (triose phosphates)
2 NAD+
4 ADP
Oxidation + ATP Formation:
Hydrogen removed from triose phosphates via oxidation. NAD+ is reduced to NADH + H+. 4 ATP produced
2 NADH + H+
4 ATP

15. 1.Phosphorylation
2.Lysis
3.Oxidation

16. Glycolysis Yield Net 2 ATP (4 produced, 2 used) 2 NADH + H+
2 pyruvate molecules
Glycolysis gives a small net gain of ATP without the use of oxygen
It is actually a complicated process

17. Mitochondria Structure

18. Stop draw and explain
Redox reactions
Glycolysis
Mitochondria

19. Transition Reaction Occurs in the mitochondrial matrix
Link between glycolysis and the Krebs cycle
Pyruvate
1C (as Co2)
NADH + H+
Pyruvate is decarboxylated
2C Acetyl +
Coenzyme A
Acetyl CoA

20. Important to Know about Transition Reaction
Pyruvate is decarboxylated and oxidized
Pyruvate is converted into acetyl compound and attached to coenzyme A to form acetyl coenzyme A

21. The Krebs Cycle: 1 Turn Location: Mitochondrial Matrix Acetyl CoA
Coenzyme A returns to link reaction and is reused
Acetyl 2C compound
Acetyl Compound (2C) combines with oxaloacetate (4C) to form citrate(6C)
Note: 1 turn of the Krebs cycle is for 1 pyruvate. Therefore 2 turns of the Krebs cycle are necessary per molecule of glucose
Oxaloacetate (4C)
Citrate (6C)
3 NADH
1 ATP
2 Carbons lost as CO2
1 FADH2

22. The Krebs Cycle
In the Krebs cycle, the oxidation of acetyl groups is coupled to the reduction of hydrogen carriers, liberating carbon dioxide
What does this mean?
citrate is oxidized
NAD is reduced to NADH
FAD is reduced to FADH2
Remember: gaining a hydrogen is reduction
Carbon dioxide is given off

23. The Krebs Cycle Yield Per Pyruvate Per Glucose (2 turns) CO2 2 4 ATP 1
NADH 3 6
FADH2

25. review

26. Stop - draw and explain
Transition reaction and krebs cycle

27. The Electron Transport Chain

28. Electron Transport Chain
Final stage of cellular respiration
What is the electron transport chain?
A series of hydrogen and electron carriers, located on the membranes of the mitochondrial cristae
This final stage involve oxidative phosphorylation and ATP generation
What is oxidative phosphorylation????

29. Electron Transport Chain
Consists of many linked proteins embedded in the cristae
These proteins are electron carriers and are reduced and oxidized as they accept and donate electrons
Inter-membrane space
Mitochondrial matrix

30. Where does the energy come from?
“Energy released by oxidation reactions is carried to the cristae of the mitochondria by reduced NAD and FAD”
Electrons from glycolysis and the Krebs cycle are transported the ETC as NADH and FADH2
The hydrogens or electrons donated from NADH and FADH2 are passed from one carrier protein to the next

31. Electron Transport Chain
Oxygen is the final electron acceptor
It is reduced to water
The ETC yields 34 ATP and water

32. Chemiosmosis in the ETC
The energy released from the electrons is used to pump H+ ions across the membrane (against the concentration gradient)
The protons move from the mitochondrial matrix to the inter-membrane space

33. Proton pumping in the ETC

34. Chemiosmosis in the ETC
The buildup of protons in the inter-membrane space creates a proton gradient
Transfer of electrons between carriers in the ETC is coupled to proton pumping

35. Chemiosmosis in the ETC
In order to even out the proton concentration, electrons flow back into the mitochondrial matrix with the concentration gradient
Protons flow down with the assistance of an enzyme called ATP synthase
As protons flow down, ADP is phosphorylated, producing ATP

36. Chemiosmosis: protons flow through ATP synthase

37. Role of Oxygen
In the ETC, oxygen is needed to bind with the free protons to maintain the hydrogen gradient
results in the formation of water

39. Note About Chemiosmosis
Proposed by Peter Mitchell- faced years of opposition before finally accepted
TOK: Why does the disproof of an old theory sometimes take a long time before the acceptance of a new one?

40. Stop- draw and explain
ETC
chemiosmosis
oxidative phosphorylation

41. Structure of Mitochondria

42. Mitochondria Structure Adapted to Function
•Matrix creates an isolated space which contains the enzymes for the Krebs cycle to occur.
•Cristae folds increase the surface area for electron transfer system.
•The double membrane creates a small space into which the H+ can be concentrated. (barrier)
•Embedded in the membrane are the enzymes and other necessary compounds for the processes of the electron transport chain and chemiosmosis to occur.

43. Electron Tomography
Provides an image of active mitochondria

44. Review
More review

45. Do Now Get goggles In a group of three or four
prepare a 40 degree water bath
5% glucose solution is on the cart
yeast suspension is in the water bath
follow steps 1-10 of the lab
look at the picture and the model set up
come back to your desks for 10 minute incubation

46. But first a little review

59. Explain aerobic respiration including oxidative phosphorylation
Big essay :)
Explain aerobic respiration including oxidative phosphorylation

60. Back to lab
step 11 and 12

62. Fermentation Anaerobic process
All organisms can metabolize glucose anaerobically (glycolysis)
Fermentation pathways do not use oxygen as a final electron acceptor
Fermentation has no further yield in ATP

63. Fermentation continued
If oxygen is not present to be the final electron acceptor (remember, anaerobic), then there must be an alternative electron acceptor otherwise glycolysis will stop
What’s the point?
To replenish NAD+ for glycolysis to continue
glycolysis has small yield of ATP

64. 2 Types of Fermentation Lactic Acid Fermentation
Results in production of lactic acid
Occurs in animals
Alcoholic Fermentation
Results in production of ethanol and carbon dioxide

65. Lactic Acid Fermentation
Occurs in animals
Why your muscles may “burn” after you work out
Lactic acid is toxic so this pathway cannot continue indefinitely
The liver converts lactic acid back into a harmless respiratory intermediate

66. Lactic Acid Fermentation
Lactate production in humans when anaerobic respiration is used maximizes the power of muscle contractions
When does this happen?

67. Alcoholic Fermentation
Occurs in yeast, some bacteria and higher plant cells

68. Alcoholic Fermentation Use
Alcoholic fermentation produces ethanol and carbon dioxide
these products are useful to the baking (CO2 for bread and other goods to rise) and brewing (ethanol in alcoholic beverages) industries
Think of how yeast is used when making bread

70. Finish lab
QUIZ NEXT CLASS
Respiration and fermentation