1 / 35

Cellular Respiration

Honors Biology. Chapter 9 Chemical Pathways. Cellular Respiration. Energy in Food: What is the difference between a: calorie(lower case c) and Calorie (upper case C)?. Basic Need for Energy.

kara
Download Presentation

Cellular Respiration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Honors Biology Chapter 9 Chemical Pathways Cellular Respiration

  2. Energy in Food: What is the difference between a: calorie(lower case c) and Calorie (upper case C)? Basic Need for Energy • A calorie is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree C. • A Calorie is a kilocalorie, or 1000 calories For example, 1 gram of glucose releases 3811 calories, on a food label 3.8 Calories

  3. Energy in Food: The reason we eat is to get energy We get carbohydrates from our food which are broken into Glucose Organisms cannot use glucose directly, it must be broken down into smaller units…… ATP Basic Need for Energy • This process in living things begins with glycolysis. • If oxygen is present, glycolysis is followed by the Krebs Cycle and electron transport chain – This is called Cellular Respiration

  4. The equation for cellular respiration is exactly the opposite of photosynthesis. Equation: An Overview:Cellular Respiration 6O2 + C6H12O6 6CO2 + 6H2O and energy

  5. Glucose needs to be broken down in small steps so that energy is not wasted. Breaking Down Energy Slowly:

  6. Definition: The process of breaking the glucose in half to form 2 molecules of pyruvate, a 3 carbon chain. Uses 2 ATP to start reaction Produces 4 ATP and 2 NADH Occurs in the Cytosol (not mitochondria) First Step: Glycolysis

  7. What is the first step of Cellular respiration? • Glycolysis • Where does it occur? • Cytosol • What goes into glycolysis? • Glucose • What comes out of glycolysis? • 2 pyruvate, 2 ATP, and 2 NADH

  8. Does not require oxygen Very Fast – thousands of ATP produced in milliseconds Stops when it runs out of NAD+ (electron carrier) If oxygen is available: Cellular respiration starts If oxygen is NOT available, to make more NAD+, your body goes through fermentation. This way ATP can be made even without Oxygen. Glycolysis

  9. You have to use a little energy to make even more energy. Like a bank, you put money in to earn interest. Net ATP gained per glucose molecule=2 Why use ATP in Glycolysis if you want ATP? Glucose Animation Pyruvate molecules

  10. Fermentation is releasing energy in the absence of oxygen. It is an ANAEROBIC process. • Ultimately it allows NADH to be converted to NAD+, allowing glycolysis to continue. • There are two main types of fermentation • Alcoholic Fermentation • Lactic Acid Fermentation Fermentation

  11. AlcohlicfermentAtion

  12. Alcoholic fermentation is found in Yeasts, and a few other microorganisms. The equation is: Pyruvic acid + NADH  alcohol + CO2 + NAD+ Note: Carbon Dioxide is also produced, so when yeast conducts fermentation, there is the release of carbon dioxide as well as alcohol. Alcoholic Fermentation

  13. Alcoholic fermentation diagram Alcoholic Fermentation

  14. AlcohlicfermentAtion

  15. Lactic Acid Fermentation

  16. Pyruvic acid from glycolysis can be converted to lactic acid. This conversion regenerates NAD+ for glycolysis to continue The equation is: Pyruvic acid + NADH  lactic acid + NAD+ Lactic acid fermentation is used by muscles when they run out of oxygen, ultimately causing soreness. Lactic acid is also created by unicellular organisms in the production of cheese, pickles, kimchi and other foods. Lactic Acid Fermentation

  17. Lactic Acid fermentation diagram Lactic Acid Fermentation

  18. Pyruvate

  19. After glycolysis, 90% of chemical energy originally in glucose still remains locked in pyruvic acid O2 is one of the most powerful electron acceptors and will help release the rest of the 90% If O2 is available to the cell, pyruvic acid heads to Krebs Cycle after glycolysis Krebs Cycle breaks pyruvic acid into CO2 Krebs Cycle and Electron Transport

  20. Where does it occur: Mitochondria It requires oxygen – it is AEROBIC It is also known as the Citric Acid Cycle Krebs Cycle

  21. Krebs Cycle • Pyruvic acid enters mitochondria • 1 carbon becomes part of CO2 and NAD+ becomes NADH • The other 2 carbons join coenzyme A to form acetyl-CoA • Acetyl-CoA adds to a 4-carbon molecule producing citric acid Animation

  22. Krebs Cycle • The citric acid is broken down to a 5-carbon then 4- carbon molecule • 2 CO2molecules are released • Electrons joinNAD+ and FAD to become NADH and FADH2 • 1 ATP made • So far, from 1 glucose • Glycolysis produced: 2 NADH and 2 ATP • Krebs Cycle produced: 8 NADH and 2 FADH2 and 2 ATP Animation

  23. Krebs Cycle Think: Does the CO2 that we breathe out come from the O2 we breathe in?

  24. Krebs Cycle

  25. Krebs Cycle • What happens to the Krebs cycle products? Carbon Dioxide is released to the atmosphere ATP is used for cellular activities NADH and FADH2 are used in the electron transport chain (next step) to produce large amounts of ATP

  26. Uses the high energy electrons from the Krebs cycle to convert ADP into ATP Electron Transport Chain

  27. Where does it occur: Inner membrane of the Mitochondria It requires oxygen – it is AEROBIC Electron Transport Chain

  28. Electron Transport Chain • NADH and FADH transfer electrons to carrier proteins • The electrons help transport H+ across membrane • Electrons move down the chain, allowing more H+ to move across • At the end of the chain, O2 acceptselectrons and left over H+, creating water, H2O Animation

  29. Electron transport chain

  30. Electron Transport Chain • The H+ builds on the outside of the membrane • The H+ moves through ATP synthase, spinning the protein • Each rotation charges an ADP, attaches a phosphate, and creates ATP Animation

  31. Cellular Respiration totals So far, from 1 glucose Glycolysis: 2 ATP Krebs Cycle: 2 ATP Electron Transport: 32 ATP Totals: 36 ATP from 1 glucose molecule This is 38% efficiency The rest of the energy is released as heat

  32. Energy use by humans • Cells contains small amounts of ready ATP • About 5 seconds worth • After that, your body uses lactic acid formation • This lasts for about 90 seconds • You breathe hard to get rid of the lactic acid buildup • For exercise longer than 90 seconds, cellular respiration is used • This is a slow method to generate ATP • Glycogen (a form of carbohydrate) is used for the first 15-20 minutes of cellular respiration • After that other molecules, such as fats, are broken down

More Related