Light energy

1. Light energy

2. Light energy Chloroplast Mitochondria

3. Cellular respirationGlycolysis (anaerboic)= cytosolKrebs (Aerobic)= Mitochondrial MatrixETC (aerobic)= cristae

4. Cell respiration The big Picture • The big picture • http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html • (google Cell Resp WH Freeman)

5. The big picture

6. Parts of Cellular respiration • Glycolysis • Organic compounds are converted into three carbon molecules of pyruvic acid, producing ATP and NADH. This process is anaerobic, and does not require oxygen • Aerobic respiration • If oxygen is present in the cell’s environment, pyruvic acid is broken down and NADH is used to make a large amount of ATP • If no oxygen is present, fermentation will occur

7. Some terms… NADH is an ELECTRON carrier molecule. Therefore, it is an energy transfer molecule used throughout the process of cellular respiration. NAD+ is electron deficient, while NADH is electron rich.

8. FADH2 is another ELECTRON carrier molecule. Therefore, it is an energy transfer molecule used throughout the process of cellular respiration. FAD is electron deficient, while FADH2 is electron rich. This molecule us used during the Krebs cycle.

10. Glycolysis • The process by which cells make ATP by breaking down organic compounds is cellular respiration. • Both anaerobic and aerobic respiration begin with the process of glycolysis. Glycolysis is not oxygen dependent. It occurs in the cytoplasm of the cell. Overall reaction: Glucose + 2 ATP Pyruvic acid + 4 ATP(occurs in cytosol)

11. Glucose + 2 ATP Pyruvic acid + 4 ATP(occurs in cytosol) • 1)Two phosphate groups are attached to glucose, forming a new 6-C compound. The two phosphate groups are supplied by 2 ATP (phosphorylation). • 2) The 6-C compound splits into two 3-C PGAL molecules.

12. 3) A phosphate group is added to each PGAL and H is released and accepted by NAD+, forming NADH. 4) The phosphate groups added in steps 1 & 3 are removed and 4 ATP are formed. The PGAL is converted to pyruvic acid.

13. So we break down Glucose…

14. Into pyruvic acid!

15. 2 ATP supply the energy needed to break down glucose, but 4 ATP are produced: net gain of 2 ATP Products of Glycolysis (per molecule of glucose) substance # of molecules formed pyruvic acid 2 NADH2 ATP (net) 2

17. ANAEROBIC RESPIRATION What occurs after glycolysis depends on the presence or absence of oxygen. There is no oxygen, anaerobic respiration (fermentation) will occur. Fermentation occurs in the cytoplasm. No additional ATP is produced after the glycolysis reaction, but it does regenerate NAD+ to be used for further glycolysis. If no NAD+ was available then glycolysis would cease and no further ATP would be produced. (The purpose is to regenerate NAD+/NADH)

18. Lactic acid fermentation Alcoholic Fermentation In the absence of oxygen, glycolysis will enter fermentation

19. Fermentation

20. Lactic Acid Fermentation • Converts pyruvic acid from glycolysis to lactic acid • Occurs in large muscles during vigorous exercise • The build up of lactic acid in muscles cause muscle fatigue • Used to produce yogurt and cheese

23. Alcoholic Fermentation • converts pyruvic acid from glycolysis to alcohol and CO2. • Occurs in plants cells and unicellular organisms (yeast). Wine, beer, and baking industries rely on yeast that produce these products through fermentation. 2NADH 2 NAD+ glucose -----> 2 pyruvic acid + 2 ATP ---------> 2 ethyl alcohol + 2 CO2

27. Efficiency of Glycolysis • Complete oxidation of one molecule of glucose = 686 kilocalories • Production of ATP from ADP absorbs 12 kcal Efficiency of glycolysis = energy required to make ATP energy released by oxidation of glucose = 2 ATP x 12 kcal x 100% = 3.5% 686 kcal Glycolysis releases only 3.5% of energy stored in glucose

28. *assume 1 piece = 1 glucose molecule Put it this way… • On a nutrition label, values are shown as Calories, but are actually kcal • If glycolysis only releases 3.5% of the energy in a single glucose molecule, a person would have to consume • 150/ 4 = 37.5 x 3.5% = 1.31 kcal The average person needs about 2000 kcals a day.

29. *assume 1 piece = 1 glucose molecule Put it this way… • If a person needs 2000 kcals a day, that’s 1526 twizzlers you need to eat a day – just to function! • So where does the rest of the energy come from?

30. Aerobic respiration

31. Aerobic respiration occurs in the prescience of oxygen • Krebs cycle • Electron transport chain • Occurs inside the mitochondrial matrix

32. Four stages of Aerobic respiration

33. The krebs cycle • Video

34. The Krebs cycle • The Krebs cycle is a biochemical pathway that breaks down acetyl CoA (Acetyl coenzyme A) and produces carbon dioxide, hydrogen atoms, and ATP

35. Acetyl CoA formation

36. Acetyl CoA formation • Pyruvic acid diffuses from the cytoplasm, across the mitochondrion's double outer membrane into the matrix. (remember – pyruvic acid was formed in glycolysis)

37. Step 1: Pyruvic acid loses a CO2 molecule and becomes a 2 acetyl group Acetyl group Pyruvic acid

38. Step 2: The acetyl group combines with Coenzyme A (CoA) forming acetyl-CoA (CoA = pantothenic acid = B vitamin Acetyl CoA

39. Step 3: NAD+ (nicotinamide adenine dinucleotide) accepts the hydrogen from pyruvic acid forming NADH Acetyl CoA

40. 2 2 2 2 2 Video (section 2)

41. The Krebs Cycle

42. The Krebs Cycle • 2-C Acetyl CoA combines with 4-C compound (oxaloacetate), forming a 6-C compound (citric acid). CoA is released

43. 2. Citric Acid is then broken down through a series of reactions a. citric acid releases a CO2 and H atom to form a 5-C compound

44. b. the 5-C compound release a CO2 molecule and a H atom to form a 4-C compound; NADH formed; ATP is formed co2

45. c. the 4-C compound releases a H atom to form another 4-C compound; FADH2 is formed co2

46. d. the 4-C compound releases a H atom to regenerate the oxaloacetic acid; NADH is formed co2

47. As a result of one turn of the citric acid cycle a) 2 molecules of CO2 are removed b) enough hydrogen is released to form 3 NADH and 1 FADH2 c) 1 ATP is produced directly The goal was to produce the electron carriers!!

49. The krebs cycle • Video (

50. In glycolysis one glucose is broken down into two pyruvic acid; so for every molecule of glucose two turns of the Kreb’s cycle are required; as a result the following occurs: