Cellular Respiration and Fermentation

9.1: Cellular Respiration

Chemical Energy and Food

1. How is energy expressed in food?- in CALORIES

2. What is a calorie?- THE AMOUNT OF ENERGY NEEDED TO RAISE THE TEMPERATURE OF 1 GRAM OF WATER 1 DEGREE CELCIUS.

3. How is calorie expressed?- with a capital C (Kilocalorie, or 1000 calories)

4. What types of macromolecules cells use for food?- FATS, PROTEINS, CARBOHYDRATES

Chemical Energy and Food

5. How can we tell how much energy is stored in different macromolecules?- Their CHEMICAL STRUCTURES (varies)- energy storing bonds will be different

Example:1 gram of Sugar (Glucose) 1 gram of Triglyceride

(Fats) - BEEF

Releases 3811 calories of heat energy when burned (bonds broken)

Releases 8893 calories of heat energy when burned (bonds broken)

Chemical Energy and Food

6. How do cells burn food and release energy?- Break down food molecules gradually- capture chemical energy- cells use this energy (stored in bonds) to make ATP.

Cellular Respiration

7. What is Cellular Respiration?- PROCESS THAT RELEASES ENERGY FROM FOOD IN THE PRESENCE OF OXYGEN.

8. What is the chemical reaction for cellular respiration?

6O2 + C6H12O6 6CO2 + 6H2O + Energy

Oxygen + Glucose Carbon Dioxide + Water + Energy

Stages of Cellular Respiration9. How many stages in Cellular Respiration?

- 3

10. What are the stages?- Glycolysis- Krebs Cycle- Electron Transport Chain (ETC)

11. Oxygen is required at the end of the ETC. Cells use oxygen to increase energy.

12. AEROBIC- cellular respiration that requires oxygen

Stages of Cellular Respiration13. KREBS CYCLE and ELECTRON TRANSPORT CHAIN are

aerobic cycles.

14. ANAEROBIC – does not require oxygen , and does not rely on oxygen –requiring processes to function.

15. GLYCOLYSIS is an anaerobic process. ( The end products of glycolysis are key reactants for aerobic stages.

Glycolysis

16. First Reaction in Cellular Respiration

17. Glycolysis means “ Sugar-breaking”

18. Glycolysis reactions transform glucose into 2 molecules of 3C molecule Pyruvic acid.

19. As glucose bonds are broken, energy is released.

20. What are the steps in glycolysis?

- ATP production- NADPH production

Glycolysis

ATP Production NADH Production

Needs a little energy to begin this step of glycolysis

21. 2 ATP molecules are used to start glycolysis

22. 4 ATP molecules are produced in glycolysis from 4 ADP molecules

23. 2 ATP molecules are produced for each glucose that enters this stage.

24. 4 (high energy) electrons are removed

25. E- are passed to an electron carrier called NAD+

26. NAD+ accepts 2 electrons and becomes NADH

27. NADH holds the electrons until they can be transferred to other molecules

Glycolysis

Breakdown of Glycolysis

28. 4 ATP are made (synthesized) from 4ADP

29. Out of the 4 ATP molecules 2 ATP is donated by glycolysis

30. This process is super fast, and can produce an abundant (a lot) of ATP molecules that are used for energy.

31. Does NOT require oxygen

32. 2 molecules of Pyruvic acid are produced from the breakdown of glucose.

Krebs Cycle

33. In the presence of oxygen, the pyruvic acid (produced in glycolysis) moves to the Krebs Cycle.

34. Pyruvic acid is broken down into Carbon Dioxide35. This stage of cellular respiration is known as the citric acid

cycle, because citric acid is the first compound made in this stage.

Krebs CycleCitric Acid Cycle Energy Extraction

36. Pyruvic Acid passes through the matrix of the mitochondria.

37. 1 carbon atom from the Pyruvic acid becomes part of a carbon dioxide molecule that is released into the air.

38. The remaining 2 carbon atoms from pyruvic acid form acetic acid, which combines with a compound called coenzyme A. This produces a molecule called acetyl-CoA

39. acetyl-CoA adds 2carbon acetyl group + 4carbon molecule = citric acid (6carbon molecule)

40. Citric acid is broken down into a 4carbon molecule,

41. Carbon dioxide is released. Electrons are transferred to

energy carriers.

42. 2 Carbons from citric acid is removed and releases 2 Carbon dioxide = 4 carbon molecule

43. Each turn of the cycle forms ATP.

44. Because each glucose entering glycolysis produces 2 pyruvic acids, it results in two complete turns of the Krebs Cycle (2ATP)

Krebs CycleEnergy Extraction

45. At five places in the Krebs Cycle, electron carriers accept a pair of electrons. The result is NAD turns into NADH, and FAD turns into FADH2

46. What happens to the products of Krebs Cycle

Carbon Dioxide- is not useful and is given off, when we exhale.

ATP – is used to power cell activity

NADH – in the presence of oxygen, the stored electrons are used to make large amounts of ATP

Electron Transport and ATP Syntesis

Electron Transport Chain ATP Production

NADH and FADH2 pass their electrons to the ETC chain.

In Eukaryotes the ETC is located in the mitochondria.

In prokaryotes the ETC is located in the cell membrane.

At the end of the ETC is an enzyme that combines the electrons with hydrogen and oxygen to form water.

Oxygen is the last electron acceptor of the ETC.

The waste of cellular respiration is low energy electrons and hydrogen ions.

Cells use a process called chemiosmosis to produce ATP..

Mitochondria contains enzymes called ATP synthase (to make ATP).

For each pair of electrons that move down the ETC, 3 ATP molecules are produced (made).

FermentationFermentation is the process that releases energy from food in the absence of oxygen.

47. During Fermentation NADH to NAD+ by passing electrons back to pyruvic acid. This allows glycolysis to produce a constant supply of ATP.

48. Fermentation occurs in the cytoplasm.

49. Fermentation is an anaerobic process, and paired with glycolysis are called anaerobic respiration.

50. There are two types of fermentation: ALCOHOLIC fermentation, and LACTIC ACID fermentation.

FermentationAlcoholic Fermentation Lactic Acid Fermentation

Yeasts and a few other microorganisms use alcoholic fermentation.

Alcoholic Fermentation produces ----- ethlyl alcohol and carbon dioxide.

Alcoholic fermentation after glycolisis

Pyruvic Acid + NADH -------- Alcholhol + CO2 + NAD+

Uses:Make alcoholic beveragesCauses bread dough to rise

Most organisms use this type of fermentation.

Some bacteria can produce lactic acid as a waste producct.

In this reaction pyruvic acid is converted to Lactic Acid.

Lactic acid does not give off carbon dioxide like alcoholic fermentation.

Lactic acid does generate (make) NAD+ like alcoholic fermentation.

Lactic Acid after glycolysis:

Pyruvic Acid + NADH ------ Lactic Acid+NAD+

FermentationAlcoholic Fermentation Lactic Acid Fermentation

Lactic Acid can produce:

CheeseYogurtButtermilkSour creamPicklesSauerkraut

In humans we can produce lactic acid in our muscles when we have bursts of energy.

ATP is produced in humans by way of lactic acid.

FermentationENERGY

For short , quick bursts of energy the body uses ATP already in the muscles, as well as ATP made by lactic acid fermentation.

For longer exercises or activities, cellular respiration is the only way to generate a continues supply of ATP