1. RESPIRATION Prof Nirupama Mallick
Agricultural & Food Engineering Department

2. The process of converting Food Energy into Chemical Energy (ATP).
ATPs are used to power the metabolic processes.
It is almost the reserve process of photosynthesis, which requires light energy for producing food, using carbon dioxide and producing oxygen.
Respiration is the chemical process opposite of photosynthesis because it releases energy from food, and uses oxygen and produces carbon dioxide.

3. Photosynthesis vs Respiration
Produces food
Uses food
Stores energy
Releases energy
Uses water
Produces water
Uses CO2
Produces CO2
Releases O2
Uses O2
Occurs in light
Occurs at all time
Only in cells containing chloroplasts
Occurs in all cells

6. The Overall Equation for Respiration
A common fuel molecule for cellular respiration is glucose
Glucose
Oxygen
Carbon
dioxide
Water
Energy

7. [Glucose loses electrons (and hydrogens)]
Oxidation
[Glucose loses electrons (and hydrogens)]
Glucose
Oxygen
Carbon
dioxide
Water
Reduction
[Oxygen gains electrons (and hydrogens)]

8. What is ATP? Energy currency of the cell Adenosine Triphosphate
5-Carbon sugar (Ribose)
Nitrogenous base (Adenine)
3 Phosphate groups
The chemical bonds that link the phosphate groups together are Covalent high energy bonds
When a phosphate group is removed to form ADP and P, small packets of energy are released.
As ATP is broken down, it gives off usable energy to power chemical work and gives off some nonusable energy as heat.

9. What are the Stages of Cellular Respiration?
Glycolysis
Krebs Cycle
Electron Transport Chain (ETC)/
Oxidative Phosporylation 9

10. Where Does Cellular Respiration Take Place?
It actually takes place in two parts of the cell:
Glycolysis occurs in the Cytoplasm or Cytosol
Krebs Cycle & ETC Take place in the Mitochondria 10

11. Review of Mitochondria Structure
About 1 micron diameter
Smooth outer Membrane
Folded inner membrane
Folds called Cristae
Space inside cristae called the Matrix
Intermembrane space

12. Cellular Respiration - 2 2 34
Cellular Respiration

13. GLYCOLYSIS Glyco = sweet Lysis= splitting
Embden-Meyerhoff-Parnas (EMP) Pathway
Anaerobic (does not require Oxygen)
10 steps all occurring in cytosol or cytoplasm

14. GLYCOLYSIS

21. Glycolysis Summary Requires input of 2 ATP
Takes place in the Cytosol (cytoplasm)
Doesn’t Use Oxygen
Requires input of 2 ATP
Glucose splits into two molecules of Pyruvate or Pyruvic Acid
Produces 2 NADH and 4 ATP
Net Production: 2 NADH and 2 ATP 21

22. Pyruvic acid from glycolysis is first converted into Acetyl-CoA
Pyruvate dehydrogenase

23. Net Production: 2 NADH
Releases 2 CO2

24. Krebs cycle Krebs cycle- was discovered by Sir Hans Krebs
Also called Citric acid cycle or Tricarboxylic Acid (TCA) cycle
Requires Oxygen (Aerobic)
Takes place in matrix of mitochondria

30. Krebs Cycle Summary
Cyclical series of oxidation reactions
Turns twice per glucose molecule
Each turn of the Krebs Cycle also produces 3NADH, 1FADH2, 1ATP and 2CO2
Therefore, For each Glucose molecule, the Krebs Cycle produces 6NADH, 2FADH2, 2ATP and 4CO2 30

31. Electron transport chain (ETC)
Discovered by Eugene Kennedy & Albert Lehninger (1948)
Catalyzes a flow of electrons from NADH/ FADH2 to O2
1) direct transfer of electron as in the reduction of Fe3+ to Fe 2+ and Cu2+ to Cu+
2) transfer as a hydrogen atom (H+ & e-)
Electron transport is coupled with formation of proton gradient → used for ATP synthesis

32. Electron transport chain (ETC)
Consists of 5 complexes:
– Complex I (NADH dehydrogenase)
– Complex II (Succinate dehydrogenase)
– Complex III (Ubiquinone-Cytochrome bc1 complex)
– Complex IV (Cytochrome oxidase) – Complex V (ATP synthase)

33. Electron transport chain (ETC)
Complex I : NADH to Ubiquinone
Complex II : Succinate to Ubiquinone
Complex III :Ubiquinone to Cytochrome c
Complex IV : Cytochrome c to Oxygen

36. Chemiosmosis
The steps that transport protons from Intermembrane space to matrix establishing a proton chemiosmotic gradient.
It is an energy-coupling mechanism that uses energy stored in the form of an H+ gradient across a membrane to generate ATP.

38. ATP synthase F1 F0

39. ATP Synthesis Inner mitochondrial membrane is impermeable to protons.
Proton can re-enter the matrix only through proton-specific channels (F0).
The proton-motive force that drives protons back into the matrix provides the energy for ATP synthesis, catalyzed by the F1 complex associated with F0.

40. Electron Transport Chain Summary
Occurs Across Inner Mitochondrial membrane
Uses coenzymes NAD+ and FAD+ to accept e- from glucose
NADH = 3 ATP’s
FADH2 = 2 ATP’s
34 ATP Produced
H2O Produced 40

41. Total number of ATP produced
Glycolysis ATP
2 molecules NADH ATP
Pyruvate DH complex
TCA cycle ATP
6 molecules NADH ATP
2 molecules FADH ATP
TOTAL ATP produced
ATP utilized in glycolysis 2
NET ATP PRODUCED 38

42. Fate of PYRUVATE in the absence of oxygen: Fermentation

43. Alcohol fermentation occurs in yeasts, and some bacteria
NADH
Pyruvate decarboxylase
Lactate dehydrogenase
NADH
Alcohol dehydrogenase
Alcohol fermentation occurs in yeasts, and some bacteria
Lactic acid fermentation occurs in animal muscle cells, some fungi and bacteria to make yogurt

44. Fermentation Occurs when O2 NOT present (anaerobic)
Requires NADH generated by glycolysis
Called Lactic Acid fermentation in muscle cells, some fungi and bacteria,
produces lactic acid)
Called Alcoholic fermentation in yeast (produces carbon dioxide and ethanol)
Net Gain: only 2 ATP 44

45. Cellular respiration can “burn” other kinds of molecules besides glucose
Diverse types of carbohydrates
Fats
Proteins

46. Food
Polysaccharides
Fats
Proteins
Sugars
Glycerol
Fatty acids
Amino acids
Amino groups
Acetyl-
CoA
Krebs
Cycle
Glycolysis
Electron
Transport

47. Some commercial use of fermentation: wine and beer.
Yeasts in the process of “budding” or reproducing.

48. Carbon dioxide in beer and cake- due to yeast fermentation