Cellular Respiration

1. Cellular Respiration

2. How do you know when you need to eat? • How do you feel when you are hungry? • Empty stomach • Dizzy • Weak Sensations vary from person to person but the bottom line is…

3. How do we get the energy from food????? • Through cellular respiration!

4. So what is cellular respiration? • Cellular respirationactually consists of morethan two dozen chemical reactions. Many of the reactions take place in specialized organelles—mitochondria • Process releases energy by breaking down glucose (sugars) and other food molecules in the presence of oxygen. • This process occurs in all eukaryotic cells. • 6O2+C6H12O6 6CO2 + 6H2O + energy

5. Mitochondria a close up 2 membranes Cristae – folds of the inner membrane Matrix - liquid

6. Overview of cellular respiration • There are three main stages! • Glycolysis • Krebs cycle • Electron transport chain

7. A Road Map for Cellular Respiration The three main stages of cellular respiration: • Glycolysis happens in the cell’s cytoplasm • the Krebs cycle happens in the matrix • electron transport and ATP synthase happens on the inner membrane Mitochondria are the sites of 2 stages of cellular respiration.

8. An Overview of Cellular Respiration

9. Cell Respiration Overview • Because oxygen is required for cellular respiration it is known as an aerobic process. • Always starts with glycolysis! • From there it depends on whether oxygen is present or not!

10. First Step : Glycolysis • Happens in cytoplasm • Does NOT require oxygen • Takes glucose (6C) and breaks it down into 2 pyruvic acids (3C) • Needs 2 ATP molecules • Makes 4 ATP molecules and 2 NADH energy molecules • Overall only 2 ATP molecules are made because 2 ATP molecules are used in the process

11. Glycolysis • Occurs quickly- cells can produce thousands of ATP molecules in milliseconds!

12. Stage I: Glycolysis

13. Results of Glycolysis • So what was your reactant? • Glucose • What were your products? • 4 ATP • 2 NADH • 2 pyruvic acid molecules • What was your net gain of ATP? • 2 ATP • So how much energy was used? • 2 ATP

14. What is ATP? • Chemical fuel of the cell • Made up of • 5 carbon sugar • 3 phosphate groups • Nitrogenous base- Adenine • ATP is which type of macromolecule? • Nucleic acid

15. ATP Adenine Ribose 3 Phosphate groups

16. More What is ATP and ADP? • When the bond breaks between the 2nd and 3rd phosphate groups of ATP, energy is released and ADP is formed. • When a phosphate is given away it becomes ADP (adenosine diphosphate) • ADP can be turned back into ATP when a phosphate group binds to ADP

17. What is the difference between ATP and ADP? • ATP – adenosine triphosphate • Has 3 phosphate groups • ADP – adenine diphosphate • Only has 2 phosphate groups

18. Figure 8-3 Comparison of ADP and ATP to a Battery Section 8-1 ADP ATP Energy Energy Partially charged battery Fully charged battery

19. Krebs Cycle • Happens after glycolysis • Happens in the mitochondria • Oxygen has to be present!

20. Figure 9–6 The Krebs Cycle Section 9-2

21. So What is Made in the Preparation of the Krebs Cycle and the Krebs Cycle? • The tally of products from 2 molecules of pyruvic acid is • 8 NADH • 2 FADH2 • 2 ATP • 6 CO2

22. What are NADHand FADH? • They are compounds that accept electrons in the form of hydrogen. • They store the electrons and transport them to the electron transport chain. • So they are electron carriers! • We will use the energy from themlater on!

23. Final Step : Electron Transport Chain and ATP Synthase Action • The final stage of cellular respiration occurs in the inner membranes of mitochondria. This stage has two parts: • Electron transport chain • ATP production by ATP synthase.

24. Electron Transport Chain (ETC) • Happens in the mitochondria in the cristae • Oxygen has to be present • The Electron Transport Chain is made up of a series of carrier proteins located in the inner membrane of the mitochondria. • As electrons are passed along, H+ is pumped out of the inner membrane.

25. Figure 9–7 Electron Transport Chain Section 9-2 Electron Transport Hydrogen Ion Movement Channel Mitochondrion Intermembrane Space ATP synthase Inner Membrane Matrix ATP Production

26. ATP Synthase (the final final step) • ADP needs to turn back into ATP • The enzyme ATP Synthase performs Phosphorylation (the chemical reaction that makes ATP) • H+ ions move through these to make ATP. • Lots of ATP are made

27. So what are the products of ETC and ATP Synthase(Phosphorylation)? • Water • Lots of ATP is made • About 36-38 ATP • WOW! • http://vcell.ndsu.nodak.edu/animations/etc/movie.htm

28. Total ATP • Glycolysis – 2 ATP • Krebs – 2 ATP • Electron transport chain – 36-38 ATPs

30. Flowchart Section 9-2 Cellular Respiration Glucose(C6H12O6) + Oxygen(6O2) Glycolysis KrebsCycle ElectronTransportChain Carbon Dioxide (6CO2) + Water (6H2O)

31. What happens when oxygen is not present? • Glycolysis still occurs but Krebs and ETC will not. • Anaerobic respiration – respiration then occurs when no oxygen is present • This is called FERMENTATION! • So if fermentation occurs, Krebs will not.

32. Fermentation • Happens when there is no oxygen • Fermentation allows for small amounts of ATP to be made. • There are 2 types

33. Lactic Acid Fermentation • Occurs when oxygen cannot reach the cells fast enough • Pyruvic acid gets changed into lactic acid • Leads to sore muscles

34. Alcohol Fermentation • Pyruvic acid gets changed into alcohol • Wine and beer

35. Figure 9–4 Lactic Acid Fermentation Section 9-1 Lactic acid Glucose Pyruvic acid

36. Photosynthesis

37. Autotrophs and Heterotrophs • Autotrophs – organisms that can make their own food • Example? • Heterotrophs – organisms that cannot make their own food • Example?

38. Photosynthesis • Plants use the energy from sunlight to change H2O and CO2 into carbohydrates and O2 • 6H2O + 6CO2+ Light EnergyC6H12O6+ 6O2 • Happens in the chloroplast

39. Chloroplast • Has 2 membranes • Chlorophyll – green pigment that traps sunlight and allows for photosynthesis (leaves)

40. Photosynthesis: Reactants and Products Section 8-2 Light Energy Chloroplast CO2 + H2O Sugars + O2

41. Light CO2 Sugars O2 Figure 8-7 Photosynthesis: An Overview Section 8-3 Chloroplast Chloroplast NADP+ ADP + P Light- Dependent Reactions Calvin Cycle ATP NADPH

42. Light and Pigments • For photosynthesis to occur, light and pigments are needed. • Plants gather the sun’s energy with pigments • Chlorophyll a and chlorophyll b are the main ones • Both absorb in the blue-violet and red region but reflects the green • That is why the leaves are green!!!!

43. Light and Pigments • Besides chlorophyll a and b, plants also contain the pigment carotene. • Carotene is a red and orange pigment

44. Parts of Photosynthesis • Have two major reactions – • Light dependent reactions – need light • Calvin cycle (dark reactions) – don’t need light

45. Electron Carriers • When electrons become excited from the light energy, the excited electrons need a carrier • Carrier molecule – compounds that accept a pair of high energy electrons and transfer them to another molecule • Electron carrier - NADPH

46. Light Dependent Reactions • Light is needed • ATP, NADPH (electron carrier), and oxygen are made

48. Steps to the Light Dependent Reactions • Pigments in the chloroplast absorb light • This causes the electrons to become excited and so this increases their energy level. • The high energy electrons get trapped and are sent to the electron transport chain!

49. Figure 8-10 Light-Dependent Reactions Section 8-3 Hydrogen Ion Movement Chloroplast Photosystem II ATP synthase Inner Thylakoid Space Thylakoid Membrane Stroma Electron Transport Chain Photosystem I ATP Formation

50. Light Dependent Reactions 4. New electrons need to replace the stolen ones. • The new electrons come from the H in water. • The O2 left over is released into the air 5. The captured electrons go are energized and go through the electron transport chain. 6. As electrons moved through the chain, H+ ions are pumped across a membrane 7. Pigments again use the energy from light to reenergize electrons so that NADPH can be made.