1. Chapter 4: Cellular Respiration

2. Everything that is alive needs energy.
Energy is the ability to do work
Without the ability to produce & use energy living things would cease to exist.

3. Adenosine Triphosphate
ATP
One of the most important compounds that cells use to store and release energy
ATP can easily release and store energy by breaking and making the bonds between its phosphate groups
The “sugar lump” of the cell
An efficient way to temporarily store energy that can be quickly released by one reaction

4. ATP Stores its energy in its chemical bonds
Energy can be converted into electrical energy, into other chemical bonds, or into power

5. ATP Drives ion pumps to restore an electrical potential
powers movement
Used for just about every process in the body that requires energy

6. Composition of ATP Adenine Ribose (5-C Sugar) 3 Phosphate Groups
Adenine + Ribose = Adenosine

7. ADP Adenosine diphosphate
looks almost like ATP, except that it has two phosphate groups instead of three.
Adenonine
Ribose
2 Phosphate Groups
ADP contains some energy, but not as much as ATP.

8. When a cell has energy available, it can store small amounts of it by adding phosphate groups to ADP, producing ATP.
ADP is like a rechargeable battery that powers the machinery of the cell.

9. AMP Adenosine monophosphate Like an uncharged battery
Adenine
Ribose
1Phosphate Group
Like an uncharged battery
Stores the least amount of energy

10. Production of ATP from ADP & AMP
Cells can release the energy stored in ATP by breaking the bonds between phosphate groups
Because a cell can add or subtract these phosphate groups, it has an efficient way of storing and releasing energy as needed.

11. Animal & Plant cells produce their own ATP through chemical reactions

12. ATP can be produced from ADP
ADP + P + Energy  ATP

13. ATP can be produced from AMP
AMP + P + P + Energy  ATP

14. Animal & Plant Cells can use ATP through the following reaction
ATP  ADP + P + Energy

15. Where do we get ATP? Adenosine
The cell gets adenosine either by absorbing food which contains adenosine or by making adenosine through a series of reactions
All cells have the capability of producing this important compound

16. Phosphate Groups Plant cells get their phosphate groups from the soil
Animal cells get their phosphate groups from absorbed food

17. Cells break down food molecules gradually and use the energy stored in the chemical bonds to produce compounds such as ATP that power the activities of the cell.

18. ATP & Long-Term Storage
ATP is not a good molecule for storing large amounts of energy over the long term.
It is more efficient for cells to keep only a small supply of ATP on hand. Cells can regenerate ATP from ADP as needed by using the energy in foods like glucose.
Why?
. A single molecule of glucose stores more than 90 times the chemical energy of a molecules of ATP.

19. When your body needs to use energy, you break down ATP to ADP to AMP.
When your body is making energy you are building AMP to ADP to ATP

20. Examples of Using & Storing ATP

21. Energy is made available for use.
1. Your body is requesting energy in order to allow your muscles to lift a box. How will ATP be used in this situation?
ATP  ADP + P + Energy
Energy is made available for use.

22. Energy is stored for later usage
2. You eat dinner. In doing this, you are producing energy. How will ATP be used in this situation?
ADP + P + Energy  ATP
Energy is stored for later usage

23. Cellular Respiration

24. Cellular Respiration
Process by which the chemical energy of “food” molecules is released & partially captured in the form of ATP

25. Carbohydrates, fats, and proteins can all be used as fuels for cellular respiration

26. Cellular Respiration can be divided into 3 processes
1. Glycolysis
2. Krebs Cycle
3. Oxidative Phosphorylation
via the electron transport chain

27. Where does this happen? 1. Glycolysis 2. Krebs Cycle
cytoplasm
2. Krebs Cycle
in mitochondrial matrix
3. Oxidative phosphorylation
on mitochondria

28. Each molecule of glucose
can generate a total of 36 ATP molecules during cellular respiration
only 2 ATP molecules through glycolysis (fermentation).

29. Glycolysis Breakdown of glucose inside the cell; “sugar breaking”
Process in which glucose is broken down in order to utilize Potential Energy stored in this molecule

30. Glucose
Chemical formula of glucose
C6H12O6

31. Gylcolysis Net gain of 2ATP & 2NADH
Glucose is broken down into pyruvate (Pyruvic acid)
Glycolysis –does not require oxygen

32. Steps to Glycolysis
1. 2ATP molecules convert glucose into a high energy C sugar with 2 phosphates
2. 6-C sugar broken down to two-3C molecules called PGAL

33. 3. 2 PGAL go to chemical reactions to make pyruvic acid (pyruvate)
Producing 4ATP molecules for each molecule of glucose
2 pair of high energy e- are produced & carried by NADH
Net gain of 2 ATP & 2 NADH

35. Why is there only a net gain of 2 ATP?
Glycolysis produces 4 ATP, but 2 ATP molecules are used to start the process therefore yielding a net gain of 2 ATP

36. If oxygen is present after glycolysis:
Pyruvate will move to the Krebs cycle when oxygen is present (aerobic respiration)

37. If no oxygen is present after glycolysis:
If oxygen is not present (anerobic respiration) then pyruvate will go through the process of fermentation.

38. Anaerobic “without air”

39. Lactic Acid Fermentation
In the absence of oxygen
In most animals pyruvic acid is converted to lactic acid when it accepts electrons from NAD+
Lactic acid is produced in your muscles during vigorous exercise

40. When you cannot supply enough oxygen to your muscles, lactic acid forms to help produce ATP
Causes a painful burning sensation in muscles

41. Lactic Acid Fermentation Chemical Reaction
Pyruvic Acid + NADH  Lactic acid + NAD+

42. Alcoholic Fermentation
Only occurs in yeast
Pyruvic acid is broken down into alcohol & CO2

43. Causes bread dough to rise, produces tiny bubbles in beer & sparkling wine as well as the alcohol content
Anaerobic process

44. Alcoholic Fermentation Reaction
Pyruvic Acid + NADH  Alcohol + CO2 + NAD+

45. Kreb’s Cycle aka Citric Acid Cycle Takes place in the mitochondria
Generates a pool of energy (ATP, NADH, FADH2) from the oxidation of pyruvate (glycolysis)

46. takes pyruvic acid ( which is broken down by glycolysis)to ATP the body can use as energy
CO2 is released in this process
This is why we breathe out CO2

47. Pyruvate is transported to the mitochondria & loses CO2 to form acetly-CoA (a 2-C molecule)
Chemical energy is released and captured in the form of NADH, FADH2, & ATP

48. Remember! Each molecule of glucose results in 2 molecules of pyruvic acid, which enter the Krebs cycle. So each molecule of glucose results in two complete “turns” of the Krebs cycle.

49. Kreb’s Cycle Products Per Glucose Molecule
Therefore, for each glucose molecule, 6 CO2 molecules, 2 ATP molecules, 8 NADH molecules, and 2 FADH2 molecules are produced.

51. Electron Transport Chain
ETC
The electron transport chain uses the high-energy electrons from glycolysis and the Krebs cycle to convert ADP into ATP.
Allows for the release of the large amount of chemical energy stored in reduced NAD+ (NADH) and reduced FAD (FADH2)
The energy released is captured in the form of ATP. (3ATP per NADH and 2 ATP per FADH2)
H2O is produced as a by-product

52. NADH and FADH2 pass their high-energy electrons to electron carrier proteins in the electron transport chain.
At the end of the electron transport chain, the electrons combine with H+ ions and oxygen to form water.
Energy generated by the electron transport chain is used to move H+ ions against a concentration gradient across the inner mitochondrial membrane and into the intermembrane space.
H+ ions pass back across the mitochondrial membrane through the ATP synthase, causing the ATP synthase molecule to spin. With each rotation, the ATP synthase attaches a phosphate to ADP to produce ATP.

53. The energy released is captured in the form of ATP
The energy released is captured in the form of ATP. (3ATP per NADH and 2 ATP per FADH2)

55. Electron Transport
NADH and FADH2 pass their high-energy electrons to electron carrier proteins in the electron transport chain.

56. At the end of the electron transport chain, the electrons combine with H+ ions and oxygen to form water.

57. Energy generated by the electron transport chain is used to move H+ ions against a concentration gradient across the inner mitochondrial membrane and into the intermembrane space.

58. ATP Production
H+ ions pass back across the mitochondrial membrane through the ATP synthase, causing the ATP synthase molecule to spin. With each rotation, the ATP synthase attaches a phosphate to ADP to produce ATP.

61. Total Breakdown of Glucose
Glycolysis  2 ATP
Kreb’s Cycle  2 ATP
ETC  32 ATP
Total 36 ATP from aerobic cellular respiration