Cellular respiration 2017 1 Organisms obtain the energy

Cellular respiration 2017

1. Organisms obtain the energy they need from the breakdown of food molecules by cellular respiration and fermentation.

9. 1 Chemical Energy and Food 2. Organisms get the energy they need from food.

3. calorie (250) – amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius.

4. Cellular respiration (251) is the process that releases energy from food in the presence of oxygen.

5. The summary of cellular respiration is presented below. In symbols: 6 O 2 + C 6 H 12 O 6 6 CO 2 + 6 H 2 O + Energy In words: Oxygen + Glucose Carbon dioxide + Water + Energy

6. Stages of cellular respiration: glycolysis, Kreb’s Cycle, and Electron transport chain

7. Cellular respiration takes place in the mitochondria of all cells.

8. The three different stages have different requirements for oxygen. aerobic (252) in air anaerobic (252) – without air

9. Comparing photosynthesis to cellular respiration: Photosynthesis removes carbon dioxide from the atmosphere, and cellular respiration puts it back. Photosynthesis releases oxygen into the atmosphere, and cellular respiration uses that oxygen to release energy from food.

Comparing Cellular respiration Photosynthesis

9. 2 The Process of Cellular Respiration 10. During glycolysis, 1 molecule of glucose, a 6 carbon compound, is transformed into 2 molecules of pyruvic acid, a 3 carbon compound. (254) ATP and NADH are also produced. The process takes place in the cytoplasm where there is no oxygen. Therefore, glycolysis is an anaerobic process.

Three Steps 2 NADH Glycolysis 2 ATP Kreb’s Cycle Electron Transport Chain

11. NAD+ (255) – electron carrier found in the cytoplasm of mitochondria. It is involved in glycolysis. 12. NADH – when NAD+ accepts 2 high energy electrons it becomes NADH

13. Steps of glycolysis: Two ATP molecules are needed to get the glycolysis process going. Overall, 4 ATP molecules are produced, for a net gain of 2 ATP per molecule of glucose in glycolysis. Four high energy electrons are passed to the carrier NAD+ to produce NADH carries these electrons to the electron transport chain.

Three Steps 2 FADH 2 2 NADH Glycolysis 2 ATP 2 NADH 6 NADH Acetyl Co. A Kreb’s Cycle 2 ATP Electron Transport Chain 32

14. During the Krebs cycle(256), pyruvic acid is broken down into carbon dioxide, NADH, ATP, and FADH 2.

15. matrix (256) – innermost compartment of the mitochondrion and the site of Krebs cycle reactions. There is oxygen there so it is an aerobic process.

16. FAD – electron carrier 17. FADH 2 –electron carrier FAD combined with 2 e- and a H+ ion 2 NADH Glycolysis 2 ATP 8 NADH 2 FADH 2 Kreb’s Cycle 2 ATP Electron Transport Chain

18. Steps of Krebs cycle – a. Pyruvic acid from glycolysis is used to make carbon dioxide, ATP, FADH 2. b. Pyruvic acid reacts to form acetyl Co. A which then enters the Kreb cycle. c. In that process, a molecule of CO 2 is produced and 2 high energy electrons are passed to NAD+ to produce NADH.

Three Steps 2 FADH 2 2 NADH Glycolysis 2 ATP 2 NADH 6 NADH Acetyl Co. A Kreb’s Cycle 2 ATP Electron Transport Chain 32

d. Acetyl Co. A combines with a 4 carbon compound in the Krebs cycle to produce citric acid. e. Citric acid is then broken down through many reactions into a 4 and 5 carbon compound. Along the way some 2 CO 2 molecules are released.

f. The 4 carbon compound can then start the cycle over again by combining with acetyl Co. A. g. Energy released by the breaking and rearranging of carbon bonds is captured in the forms of ATP, NADH, and FADH 2.

19. Because glycolysis produces two molecules of pyruvic acid from each glucose molecule, the Krebs cycle turns twice for each glucose molecule that enters glycolysis.

20. The electron transport chain uses the high energy electrons transported by the carrier molecules NADH from both the Krebs cycle and glycolysis, and FADH 2 from the Krebs cycle to convert ADP into ATP.

• 21. The electron transport chain takes place in the inner mitochondrial membrane. • There is oxygen there so it is an aerobic process.

22. Intermembrane space is the space between the inner membrane and the outer membrane of the mitochondria.

23. Steps of electron transport chain: a. High energy electrons from NADH and FADH 2 are passed from carrier to carrier, down the electron transport chain. b. Water is formed when oxygen accepts the electrons in combination with hydrogen ions.

c. Energy generated by the electron transport chain is used to move H+ ions across the inner mitochondrial membrane and into the intermembrane space.

• d. ATP Production – H+ ions pass back across the mitochondrial membrane through ATP synthase causing the base of the synthase molecule to rotate. With each rotation, driven by the movement of the H+ ion, ATP synthase generates ATP from ADP.

24. The totals of ATP generated through cellular respiration Glycolysis – 2 ATP Krebs cycle – 2 ATP Electron transport chain – 32 ATP

25. Together, glycolysis, the Krebs cycle, and the electron transport chain release about 36 molecules of ATP per molecule of glucose.

Reactants Products Glycolysis Cytoplasm outside mitochondria C 6 H 12 O 6 2 ATP NADH 4 molecules ATP Net gain only 2 2 pyruvate molecules Krebs Cycle In matrix of mitochondria 4 CO 2 2 ATP NADH & FADH 2 6 O 2 Electron Transport Chain Mitochondria inner membrane 32 ATP 6 H 20

Photosynthesis No. of steps Names of steps 2 Light independent cycle Light dependent cycle Alternate pathways C 4 and CAM Cellular respiration 3 Glycolysis Krebs cycle Electron Transport Cycle Lactic acid fermentation Alcohol fermentation

• Fermentation is a way to release energy from food molecules by producing ATP without oxygen. • Two types • Alcoholic fermentation • Lactic acid fermentation

• What are the similarities?

What are the differences?

How is each one used? • Used for energy in yeast & microorganisms • Produces alcoholic beverages & yeast bread • Bacteria use it for energy • Certain foods use the lactic acid for flavoring; cheese, yogurt, buttermilk, sour cream, pickles & sauerkraut • Humans use lactic acid fermentation when cells are out of oxygen; best at this muscle cells

9. 1 assessment 1. a. Review Why do all organisms need food? to gain energy to undergo processes of life b. Relate Cause and Effect Why do macromolecules differ in the amount of energy they contain? chemical structures differ in carbs, proteins, and fats so therefore the energy contained in their chemical bonds, differ.

2. a. Review Write the overall reaction for cellular respiration. 6 O 2 + C 6 H 12 O 6 → 6 CO 2 + 6 H 2 O + Energy b. Apply Concepts How does the process of cellular respiration maintain homeostasis at the cellular level? Remember plasma membrane controls homeostasis Things need to get in and out of cell to maintain homeostasis and some of them need the energy from break down of food to move things in and out of cell

3. a. Review In what ways are cellular respiration and photosynthesis considered opposite processes? Cellular respiration breaks down glucose; photosynthesis builds it Cellular respiration uses oxygen; photosynthesis breaks H 20 and releases oxygen. b. Use Analogies How is the chemical energy in glucose similar to money in a savings account? Chemical energy is stored in the bonds of glucose, just as money is stored in a savings account

9. 2 assessment 1 a. Review What are the products of glycolysis? 2 molecules of pyruvic acid 2 molecules of NADH a net gain of 2 ATP molecules

b. Compare and Contrast How is the function of NAD+ similar to that of NADP+? Both electron carriers

2. a. Review What happens to pyruvic acid in the Krebs cycle? Pyruvic acid is broken down into carbon dioxide

b. Interpret Visuals Look at Figure 9– 5 and list the products of the Krebs cycle. What happens to each of these products? CO 2 is expelled in exhalation. The ATP molecules are used to power cellular activities. The NADH and FADH 2 molecules are used in the electron transport chain to generate more ATP.

3. a. Review How does the electron transport chain use the high energy electrons from glycolysis and the Krebs cycle? to power the “pumping” of H+ ions against a concentration gradient from the matrix to the intermembrane space

3. b. Relate Cause and Effect How does the cell use the charge differences that build up across the inner mitochondrial membrane during cellular respiration? The charge differences force protons through ATP synthase, which powers the conversion of ADP to ATP.

4. a. Review How many molecules of ATP are produced in the entire breakdown of glucose? about 36 molecules of ATP per molecule of glucose b. Use Analogies How is the cell like a furnace? It can “burn” many different types of fuels, not just glucose. Also, a cell releases heat energy through the breakdown of glucose that heats the organism, just as a furnace releases energy to heat a building

9. 3 assessment 1. a. Review Name the two main types of fermentation. Lactic acid fermentation and alcoholic fermentation b. Compare and Contrast How are alcoholic fermentation and lactic acid fermentation similar? Both forms provide energy to the cell in the absence of oxygen, and both produce NAD+. How are they different? They are different in that alcoholic fermentation produces alcohol and carbon dioxide, while lactic acid fermentation produces lactic acid.

2. a. Review Why do runners breathe heavily after a sprint race? When the race is over, the only way to get rid of lactic acid is through a chemical pathway that requires extra oxygen. b. Sequence List the body’s sources of energy in the order in which they are used during a long distance race. ATP already in muscles ATP made by lactic acid fermentation ATP produced by cellular respiration