Cellular Respiration

Transcription

1 Cellular Respiration

2 Chemical Equation 6 O 2 + C 6 H 12 O 6 6 H 2 O + 6 CO 2 +

3 Page 107 Adenosine Triphosphate Adenosine Diphosphate

4 Background Aerobic= requires oxygen Anaerobic= does not require oxygen Usually think of respiration as breathing, but cellular respiration refers to the energy-releasing pathways However, we breathe to get oxygen to fuel the cellular respiration

5 1 st Step- Glycolysis (breaking apart glucose) Occurs in the cytoplasm Requires 2 to make 4 = NET GAIN OF 2 Pyruvate is made Next step depends on whether there is oxygen present or not

6 Step 2-If oxygen is present aerobic Glycolysis is followed by the Krebs cycle/citric Acid Cycle and then the electron transport chain Occurs in the mitochondria Yields 34 more

7 2a- Krebs Cycle Pyruvate is broken down into carbon dioxide in a series of energy-extracting reactions. (thus resulting in the CO2 we exhale) 2 s are made High energy electrons transferred to electron carriers, (NAD +, FADH) NADH & FADH 2

8 The Citric Acid Cycle Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. NADH NADH NADH and FADH2 Glycolysis Preparatory reaction glucose pyruvate Citric acid cycle Electron transport chain and chemiosmosis 2 2 ADP 4 ADP 2 4 total net 32 ADP 2 ADP 2 32 or 34 or 34 NAD + NADH 1. The cycle begins when an acetyl group carried by CoA combines with a C 4 molecule to form citrate. acetyl CoA CoA oxaloacetate C 4 citrate C 6 Citric acid cycle ketoglutarate C 5 CO 2 NAD + 2. Twice over, substrates are oxidized as NAD + is reduced to NADH, and CO 2 is released. NADH 5. Once again a substrate is oxidized, and NAD + is reduced to NADH. NAD + fumarate C 4 succinate C 4 CO 2 NADH FAD 4. Again a substrate is oxidized, but this time FAD is reduced to FADH 2. FADH 2 3. is produced as an energized phosphate is transferred from a substrate to ADP.

9 Citric Acid Cycle: Balance Sheet Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. inputs 2 pyruvates 6 NAD + 2 FAD Citric acid cycle outputs 4 CO 2 6 NADH 2 FADH 2 2 ADP + 2 P 2 9

10 Electron Transport Chain ETC uses high energy electrons from the Krebs cycle to convert ADP to. Massive amounts of are generated. (32 s) Oxygen is a reactant & water is also a product

11 Electron Transport Chain Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. NADH e NADH e e NADH and e e FADH 2 e Glycolysis Preparatory reaction glucose pyruvate Citric acid cycle e Electron transport chain and chemiosmosis ADP 4 ADP total 2 ADP net 2 ADP 2 ADP 32 or ADP 32 or ADP NADH +H + e - NAD + + 2H + NADH-Q reductase P 2e - made by chemiosmosis coenzyme Q e - FADH 2 2e - FAD + 2H + cytochrome reductase 2e - cytochrome c ADP + P made by chemiosmosis 2e - cytochrome oxidase 2e - 2 H + ADP + P made by chemiosmosis 1 / 2 O 2 H 2 O 11

12 Overall Energy Yielded per Glucose Molecule Mitochondrion Cytoplasm Electron transport chain Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. glucose 2 net A T P 2 pyruvate glycolysis 2 NADH 4 or 6 2 acetyl CoA 2 NADH 6 2 CO 2 6 NADH 18 2 Citric acid cycle 4 CO 2 2 FADH 2 4 P subtotal 4 6 O 2 6 H 2 O subtotal 32 or or 38 total 12

13 Energy and Exercise Quick energy- cells contain enough for a few seconds Lactic acid fermentation- can provide enough energy for about 90 seconds of work Reason a runner breathes so heavily after a race Lactic acid causes soreness Long-Term energy- comes from respiration comes from glycogen stored in cells for minutes After that, body breaks down other stored food molecules, including fats Reason aerobic exercise is beneficial for weight control

14 The Metabolic Pool Concept Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. proteins carbohydrates fats amino acids glucose glycerol fatty acids Glycolysis pyruvate acetyl CoA Citric acid cycle Electron transport chain 14 C Squared Studios/Getty Images.

15 Vocabulary Calorie- the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius Glycolysis- the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid. Cellular respiration- the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen NAD+ - an electron carrier Fermentation- the pathway that allows glycolysis to continue by returning electrons to pyruvic acid

16 Anaerobic- oxygen is not required Aerobic- oxygen is required Kreb s cycle- the process in which pyruvic acid is broken down into carbon dioxide in a series of energy-releasing steps Electron transport chain- the process in which high-energy electrons convert ADP to (a lot of it). - the principal chemical compound that cells use to store and release energy

17 Step 2-If oxygen is not present = anaerobic Fermentation- process that allows glycolysis to continue by returning electrons to pyruvate Therefore, 2 more s will be made then 2 more then 2 more

18 Two Types of Fermentation Alcoholic fermentation- occurs in yeast and bacteria Yeast are unicellular eukaryotic fungi that carry out aerobic respiration, however when oxygen is not available, they can switch to anaerobic respiration Pyruvate + NADH ethanol + NAD + + CO 2 Very important in industry alcohol, bread, ethanol for fuel Lactic acid fermentation occurs in muscles During strenuous exercise when your lungs cannot provide you with enough oxygen, your muscles switch to lactic acid fermentation most of the lactic acid diffuses into the bloodstream and goes to the liver to be converted back to Pyruvate, however some remains and causes soreness. Pyruvate + NADH lactic acid + NAD +

19 Glycolysis: Inputs and Outputs Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display inputs glucose 2 NAD + Glycolysis outputs 2 pyruvate 2 NADH 2 2 ADP 4 ADP + 4 P 4 total 2 net gain 19

20 Summary-Aerobic Anaerobic Cycle Net production Cycle Net production Glycolysis 2 Glycolysis 2 Krebs Cycle 2 Fermentation Electron Transport Chain Total Glycolysis Total 2 Depends on # of cycles

21 Glucose Breakdown: Overview of 4 Phases Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display NADH e NADH e e Cytoplasm e e NADH and FADH 2 Mitochondrion e e glucose Glycolysis pyruvate Preparatory reaction Citric acid cycle Electron transport chain and chemiosmosis ADP 4 total 2 net gain 2 AD P 2 32 ADP 32 or 34 or 34 21

22 Chemical Equations Cellular Respiration O 2 + C 6 H 12 O 6 CO 2 + H 2 O + energy Oxygen + glucose Carbon Dioxide + Water + Photosynthesis CO 2 + H 2 O + energy O 2 + C 6 H 12 O 6 Carbon Dioxide + Water + sunlight Oxygen + glucose

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24 Energy in the biosphere Starts with the sun Plants take in sunlight and convert the energy via photosynthesis into sugars. Extra energy is stored as starches and cellulose. Animals eat plants and convert energy into. Extra energy or calories are stored as glycogen and fats. When animals die, the energy gets released back to the ecosystem by bacteria digesting the bodies. Food chain

25 Real-life applications A calorie is how we measure the amount of energy stored in foods. This is because it is the extra energy taken by plants from the sun, or other animals from their food and stored. Therefore, if you take in more energy than you are using, you also store that extra energy in glycogen and fat.