Chapter 9 Cellular Respiration -...

Biology IIChapter 9 Cellular Respiration

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Tabla de contenidoSummary...............................................................................................................................................2

Vocabulary Review................................................................................................................................3

The Mitochondrion................................................................................................................................4

Cellular Respiration Overview...............................................................................................................4

Glycolysis and Fermentation.................................................................................................................5

9-1 Chemical Pathways.........................................................................................................................5

Workbook Section 9–1 Chemical Pathways (pages 221–225)...............................................................6

Enrichment -- Lactobacillus..................................................................................................................7

Section Review 9-1................................................................................................................................8

The Krebs Cycle....................................................................................................................................9

Electron Transport Chain.....................................................................................................................10

9-2 The Krebs Cycle and Electron Transport......................................................................................11

Section 9–2 The Krebs Cycle and Electron Transport (pages 226–232)...............................................12

9-2 Section Reviewing Key Concepts.................................................................................................15

WordWise............................................................................................................................................15

Vocabulary Review..............................................................................................................................17

Graphic Organizer...............................................................................................................................18

Chapter Assessment 9..........................................................................................................................19


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Summary9–1 Chemical Pathways

Food serves as the source of energy for cells. Quite a lot of energy is stored in food. For instance, 1 gram of the sugar glucose releases 3811 calories of heat energy when burned in the presence of oxygen. A calorie is the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius. Cells don’t burn glucose and other food compounds. They gradually release the energy. The process begins with a pathway called glycolysis. In the presence of oxygen, glycolysis is followed by the Krebs cycle and the electron transport chain. Together, these three pathways make up cellular respiration. Cellular respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen. The equation for cellular respiration is:6O2 + C6H12O6 ➞ 6CO2 + 6H2O + Energyoxygen + glucose ➞ carbon + water + energy dioxideThere are three main stages of cellular respiration: (1) glycolysis, (2) the Krebs cycle, and (3) electron transport.

Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3- carbon compound. Through glycolysis, the cell gains 2 ATP molecules. In one of the reactions of glycolysis, the electron carrier NAD+ accepts a pair of high-energy electrons, producing NADH. By doing this, NAD+ helps pass energy from glucose to other pathways in the cell.

When oxygen is not present, glycolysis is followed by another pathway. This pathway is called fermentation. Fermentation releases energy from food molecules by producing ATP. Because fermentation does not require oxygen, it is said to be anaerobic. During fermentation, cells convert NADH back into the electron carrier NAD+, which is needed for glycolysis. This action allows glycolysis to continue producing a steady supply of ATP. The two main types of fermentation are alcoholic fermentation and lactic acid fermentation. Yeasts and a few other microorganisms carry out alcoholic fermentation. The equation for alcoholic fermentation after glycolysis is: pyruvic + NADH ➞ alcohol + CO2 + NAD+ acidLactic acid fermentation occurs in your muscles during rapid exercise. The equation for lactic acid fermentation after glycolysis is: pyruvic acid + NADH ➞ lactic acid + NAD+

9–2 The Krebs Cycle and Electron TransportWhen oxygen is available, glycolysis is followed by the Krebs cycle and the electron transport chain. The three pathways together make up the process of cellular respiration. Because the pathways of cellular respiration require oxygen, they are said to be aerobic.

The Krebs cycle is the second stage of cellular respiration. In eukaryotes, the Krebs cycle takes place in the mitochondrion. During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions. The Krebs cycle is also known as the citric acid cycle, because citric acid is one of the first products. The Krebs cycle begins when pyruvic acid produced by glycolysis enters the mitochondrion. One carbon atom from pyruvic acid becomes part of a molecule of carbon dioxide, which is eventually released into the air. The carbon dioxide released during the Krebs cycle is the source of much of the carbon dioxide in air. The other two carbon atoms from pyruvic acid are used in a series of reactions. During these reactions, two energy carriers accept high-energy electrons. NAD+ is changed to NADH, and FAD is changed to FADH2. These molecules carry the high-energy electrons to the electron transport chain.


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Electron transport is the third stage of cellular respiration. The electron transport chain uses the high-energy electrons from the Krebs cycle to convert ADP into ATP. In eukaryotes, the electron transport chain is composed of a series of carrier proteins located in the inner membrane of the mitochondrion. In prokaryotes, the same chain is in the cell membrane. In this pathway, high-energy electrons move from one carrier protein to the next. Their energy is used to move hydrogen ions across the membrane through a protein sphere called ATP synthase. Each time an ATP synthase spins, a phosphate group is added to an ADP molecule, producing an ATP molecule. In the absence of oxygen, all the energy that a cell can extract from a single molecule of glucose is 2 ATP molecules—the product of glycolysis.

In the presence of oxygen, though, the cell can extract many more ATP molecules. The Krebs cycle and the electron transport chain enable the cell to produce 34 more ATPmolecules per glucose molecule. The total, then, for cellular respiration—glycolysis plus the Krebs cycle plus electron transport— is 36 ATP molecules per glucose molecule.

Human body cells normally contain small amounts of ATP produced during cellular respiration. When the body needs energy in a hurry, muscle cells produce ATP by lactic acid fermentation. For long-term energy needs, the body must use cellular respiration.

The energy flows in photosynthesis and cellular respiration take place in opposite directions. On a global level, photosynthesis and cellular respiration are also opposites. Photosynthesis removes carbon dioxide from the atmosphere and puts back oxygen. Cellular respiration removes oxygen from the atmosphere and puts back carbon dioxide.

Vocabulary ReviewMatching In the space provided, write the letter of the definition that best matches each term._____ 1. calorie_____ 2. glycolysis_____ 3. cellular respiration_____ 4. NAD+_____ 5. fermentation_____ 6. anaerobic_____ 7. Aerobic

a. electron carrierb. pathway that releases energy from food in theabsence of oxygen

c. requires oxygend. process in which one molecule of glucose is brokenin half, producing two molecules of pyruvic acide. does not require oxygenf. amount of energy needed to raise 1 gram of water 1degree Celsiusg. process that releases energy by breaking down foodmolecules in the presence of oxygen

Answering Questions In the space provided, write an answer to each question.8. What is the first stage of cellular respiration? _______________________________________________________________________________________________________________9. What is the second stage of cellular respiration? _____________________________________________________________________________________________________________10. What is the third stage of cellular respiration? ______________________________________________________________________________________________________________11. How many ATP molecules can the cell produce from a single molecule of glucose through glycolysis? __________________________________________________________


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12. How many ATP molecules can the cell produce from a single molecule of glucose through the complete process of cellular respiration? ________________________________Completion Write an equation for each of the pathways below.13. lactic acid fermentation after glycolysis ___________________________________________________________________________________________________________________14. alcoholic fermentation after glycolysis ___________________________________________________________________________________________________________________15. cellular respiration ___________________________________________________________________________________________________________________________________

The MitochondrionIn plant and animal cells, the final stages of cellular respiration take place in mitochondria. A mitochondrion has two membranes. The inner membrane is folded up inside the outer membrane. The space between the inner and outer membranes is called the intermembrane space. The space inside the inner membrane is called the matrix.Label the inner membrane, intermembrane space, matrix, and outer membrane.

1. In which membrane is the electron transport chain located?outer membrane inner membrane

Cellular Respiration OverviewCellular respiration is the process that releases energy from food in the presence of oxygen.

Use the words below to label the diagram of cellular respiration on the lines provided.ATP glycolysis mitochondrion

electron transport chain Krebs cycle1- _______________________2- _______________________3- _______________________


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4- _______________________5- _______________________

Use the diagram to answer the questions.1. Where does glycolysis take place?______________________________________________________________________________________________________________________________________________________

2. Where do the Kreb cycle and electron transport chain take place?______________________________________________________________________________________________________________________________________________________

Glycolysis and FermentationGlycolysis uses ATP to break a molecule of glucose in half, producing pyruvic acid. When oxygen is not present, glycolysis is followed by fermentation. Fermentation enables cells to produce energy in the absence of oxygen.Follow the prompts to identify important parts of glycolysis and fermentation.• Color the carbon atoms blue.• Circle the place where ATP is formed.• Mark an X on the place where ATP is used.

Answer the questions.1. How many carbon atoms are in one molecule of glucose? ______________________2. What is the product of glycolysis? _________________________________

9-1 Chemical Pathways

1- Describe the process of cellular respiration.______________________________________________________________________________________________________________________________________________________2- What are the products of glycolysis?


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______________________________________________________________________________________________________________________________________________________3- What is a calorie? A Calorie?______________________________________________________________________________________________________________________________________________________4- How is the function of NAD+ similar to that to NADP+?______________________________________________________________________________________________________________________________________________________5- How are lactic acid fermentation and alcoholic fermentation similar? How are they different?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Workbook Section 9–1 Chemical Pathways (pages 221–225)This section explains what cellular respiration is. It also describes what happens during glycolysis and describes two types of fermentation.Chemical Energy and Food (page 221)1. What is a calorie? ______________________________________________________________________________________________________________________________________________________2. How many calories make up 1 Calorie? _____________________________________3. Cellular respiration begins with a pathway called _________________________________4. Is the following sentence true or false? Glycolysis releases a great amount of energy. ____Overview of Cellular Respiration (page 222)5. What is cellular respiration? ____________________________________________________________________________________________________________________________6. What is the equation for cellular respiration, using chemical formulas?______________________________________________________________________________________________________________________________________________________7. What would be the problem if cellular respiration took place in just one step?______________________________________________________________________________________________________________________________________________________8. Label the three main stages of cellular respiration on the illustration of the complete process.


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9. Where does glycolysis take place? ________________________________________________________________________________________________________________________10. Where do the Krebs cycle and electron transport take place? _______________________Glycolysis (page 223)11. What is glycolysis? ___________________________________________________________________________________________________________________________________12. How does the cell get glycolysis going? _______________________________________13. If the cell uses 2 ATP molecules at the beginning of glycolysis, how does it end up with a net gain of 2 ATP molecules? ____________________________________________________________________________________________________________________________14. What is NAD+? __________________________________________________________15. What is the function of NAD+ in glycolysis? _________________________________________________________________________________________________________________________________________________________________________________________16. Why can glycolysis supply energy to cells when oxygen is not available? ________________________________________________________________________________________17. What problem does a cell have when it generates large amounts of ATP from glycolysis? ______________________________________________________________________________________________________________________________________________________Fermentation (pages 224–225)18. What is fermentation? ________________________________________________________________________________________________________________________________19. How does fermentation allow glycolysis to continue? ________________________________________________________________________________________________________20. Because fermentation does not require oxygen, it is said to be ______________________21. What are the two main types of fermentation?a.__________________________ b.___________________________22. What organisms use alcoholic fermentation? _______________________________________________________________________________________________________________23. What is the equation for alcoholic fermentation after glycolysis?___________________________________________________________________________24. What happens to the small amount of alcohol produced in alcoholic fermentation during the baking of bread? __________________________________________________________25. What does lactic acid fermentation convert into lactic acid? ________________________26. What is the equation for lactic acid fermentation after glycolysis?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________27. During rapid exercise, how do your muscle cells produce ATP?________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Enrichment -- LactobacillusWhen was the last time your body benefited from lactic acid fermentation? Perhaps it was the last time your muscles needed a quick burst of energy. However, if you’ve recently enjoyed a cup of yogurt, a slice of cheese, or some kimchi or sauerkraut with your meal, you were eating the products of lactic acid fermentation.


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Human muscle cells are not the only cells in which lactic acid fermentation occurs. In fact, there are countless organisms that take advantage of this process. Some of the most common lactic acid fermenting organisms are a group of bacteria called Lactobacillus. Lactobacillus uses lactic acid fermentation as one of its metabolic processes for producing energy. One of the byproducts of this process, lactic acid, is a useful ingredient in many foods.

Before the days of refrigeration, fresh food, especially milk, was good for only a matter of hours before it spoiled. Early people discovered, probably by accident, that fermented milk products such as yogurt would last for days or even weeks before it spoiled. The same is true for many other foods. How is this possible? The lactic acid produced by Lactobacillus inhibits the growth of other bacteria and organisms that could spoil the food.

Today, food spoilage is less of a concern than it was even a century ago. So why do people still eat foods fermented by Lactobacillus? Over the years, people learned to like the flavor of fermented foods. Lactic acid gives these foods a sour taste. If you’ve ever tried sour cream or buttermilk, you may be familiar with this taste, or even like it. Additionally, fermented milk products are high in calcium and protein, which makes them nutritious.

Evaluation On a separate sheet of paper, answer the following questions.1. Suppose you lived over 100 years ago and you had a whole bowl of fresh milk but only one cup of yogurt left. Describe how you might make more yogurt.2. How does lactic acid keep food from spoiling?

Section Review 9-1Reviewing Key ConceptsCompletion On the lines provided, complete the following sentences.1. The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen is called ________________.2. During glycolysis, one molecule of __________________________ is broken in half.3. During glycolysis, NAD_ is converted to ____________________.4. Glycolysis produces a net gain of __________________ ATP molecules for each reaction.5. The products of alcoholic fermentation are ________________________, __________________________, and _____________________________ .

Short Answer On the lines provided, answer the following questions.6. Why is fermentation considered an anaerobic process?______________________________________________________________________________________________________________________________________________________


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7. How does fermentation allow the production of ATP to continue?______________________________________________________________________________________________________________________________________________________

Reviewing Key SkillsLabeling Diagrams On the lines provided below, write the names of the substances in the glycolysis reaction that correspond to the numbers in the diagram.

8- _________________________9- _________________________10- ________________________

The Krebs CycleIf oxygen is present, the pyruvic acid formed during glycolysis moves into the Krebs cycle. The Krebs cycle converts pyruvic acid into carbon dioxide. As carbon dioxide is formed, high energy electrons are accepted by NAD_ and FAD. This results in the formation of NADH and FADH2. NADH and FADH2 will be used later to produce ATP.Follow the prompts to identify important parts of the Krebs cycle.• Color the carbon atoms blue.• Circle the electron carriers in green.• Circle ATP in orange.

1. Which of the following is formed during the Krebs cycle?FADH2 pyruvic acid


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Electron Transport ChainThe electron transport chain uses the high-energy electrons produced by the Krebs cycle to move hydrogen ions from one side of the inner membrane to the other.Label the diagram with the following terms: electron, hydrogen ion, and inner membrane

Use the diagram to answer the questions.1.-Where in the mitochondrion does the electron transport chain take place?______________________________________________________________________________________________________________________________________________________2. What happens to the high-energy electrons from the Krebs cycle?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________Cellular Respiration and PhotosynthesisCellular respiration and photosynthesis can be thought of as opposite processes. Energy flows in opposite directions in the two processes.Complete the table using the words below. Some cells have been completed for you. Some words may be used more than once.

carbon dioxide energy release mitochondria water


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Use the table to answer the questions.1. Which process releases energy for the cell? Circle the correct answer.

cellular respiration photosynthesis2. For which reaction is 6CO2 _ 6H2O ➝ C6H12O6 + 6O2 the correct equation? Circle the correct answer.

cellular respiration photosynthesis3. How do the products of photosynthesis compare to the reactants of cellular respiration?______________________________________________________________________________________________________________________________________________________

9-2 The Krebs Cycle and Electron Transport

1- What happens to pyruvic acid during the Krebs cycle?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________2- How does the electron transport chain use the high- energy electrons from the Kreb cycle?________________________________________________________________________________________________________________________________________________________________________________________________________________________________3- Why is cellular respiration considered to be much more efficient than glycolysis alone?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________4- How many molecules of ATP are produced in the entire breakdown of glucose?______________________________________________________________________________________________________________________________________________________5- Compare the energy flow in photosynthesis to the energy flow in cellular respiration.__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________6- How is the chemical energy in glucose similar to money in a savings account?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


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Section 9–2 The Krebs Cycle and Electron Transport (pages 226–232)This section describes what happens during the second stage of cellular respiration, called the Krebs cycle. It also explains how high-energy electrons are used during the third stage, called electron transport.Introduction (page 226)1. At the end of glycolysis, how much of the chemical energy in glucose is still unused?__________________________________________________________________________2. Because the final stages of cellular respiration require oxygen, they are said to be ___________________.The Krebs Cycle (pages 226–227)3. In the presence of oxygen, how is the pyruvic acid produced in glycolysis used?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________4. What happens to pyruvic acid during the Krebs cycle? ___________________________________________________________________________________________________________________________________________________________________________________5. Why is the Krebs cycle also known as the citric acid cycle? _______________________________________________________________________________________________________________________________________________________________________________6. When does the Krebs cycle begin? ___________________________________________________________________________________________________________________________________________________________________________________________________7. What happens to each of the 3 carbon atoms in pyruvic acid when it is broken down?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________8. What happens to the carbon dioxide produced in breaking down pyruvic acid?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________9. How is citric acid produced? ____________________________________________________________________________________________________________________________10. During the energy extraction part of the Krebs cycle, how many molecules of CO2 are released? __________________11. What is the energy tally from 1 molecule of pyruvic acid during the Krebs cycle?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________12. When electrons join NAD+ and FAD during the Krebs cycle, what do they form?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 13. Why is the 4-carbon compound generated in the breakdown of citric acid the only permanent compound in the Krebs cycle? _______________________________________________________________________________________________________________________________________________________________________________________________Electron Transport (pages 228–229)14. What is the electron transport chain? _________________________________________


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______________________________________________________________________________________________________________________________________________________15. What does the electron transport chain use the high-energy electrons from the Krebs cycle for? __________________________________________________________________________________________________________________________________________________16. How does the location of the electron transport chain differ in eukaryotes and prokaryotes? ___________________________________________________________________________________________________________________________________________17. Where does the electron transport chain get the high-energy electrons that are passed down the chain? ________________________________________________________________________________________________________________________________________

18. Is the following sentence true or false? Hydrogen serves as the final electron acceptor of the electron transport chain. _________________19. What is the energy of the high-energy electrons used for every time 2 high-energy electrons move down the electron transport chain?_____ ___________________________________________________________________________________________________________________________________________________________________________________20. What causes the H+ ions in the intermembrane space to move through the channels in the membrane and out into the matrix? ___________________________________________________________________________

21. On average, how many ATP molecules are produced as each pair of high-energy electrons moves down the electron transport chain? _________________________________

22. Complete the flowchart about electron transport.


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The Totals (page 229)23. What is the total number of ATP molecules formed during cellular respiration? ___________24. Why can 18 times as much ATP be generated from glucose in the presence of oxygen than when oxygen is not available? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________25. What happens to the 62 percent of the total energy of glucose that is not used to make ATP molecules? _____________________________________________________________26. What are the final waste products of cellular respiration? _________________________Energy and Exercise (pages 230–231)27. What are three sources of ATP a human body uses at the beginning of a race?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________28. When a runner needs quick energy for a short race, what source can supply enough ATP for about 90 seconds? _________________________________________________________29. Why does a sprinter have an oxygen debt to repay after the race is over?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________30. A runner needs more energy for a longer race. How does the body generate the necessary ATP? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________31. Why are aerobic forms of exercise so beneficial for weight control? __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Comparing Photosynthesis and Cellular Respiration (page 232)32. If photosynthesis is the process that “deposits” energy in a “savings account,” then what is cellular respiration?____________________________________________________________________________________________________________________________________33. How are photosynthesis and cellular respiration opposite in terms of carbon dioxide?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________34. How are photosynthesis and cellular respiration opposite in terms of oxygen?_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


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9-2 Section Reviewing Key ConceptsShort Answer On the lines provided, answer the following questions.

1. How is pyruvic acid used in the Krebs cycle?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________2. How are glycolysis and cellular respiration related? _________________________________________________________________________________________________________________________________________________________________________________________________________________________________3. What role do high-energy electrons play in the electron transport chain? _________________________________________________________________________________________________________________________________________________________________________________________________________________________________4. What are the reactants in cellular respiration? What are the products? _________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Reviewing Key SkillsIdentification On the lines provided, identify which phrase describes the following processes: cellular respiration or photosynthesis.________ 5. reactants are CO2 and H2O________ 6. occurs only in plants, algae, and some microorganisms________ 7. 6O2 _ C6H12O6 → 6CO2 _ 6H2O _ Energy________ 8. uses oxygen to release energy from food9. Comparing How many ATP molecules are produced in glycolysis? In cellular respiration? _________________________________________________________________________________________________________________________________________________________________________________________________________________________________10. Applying Concepts Would a baseball player running to first base and a cross-country skier use the same or different pathways to release energy? Explain your answer. _________________________________________________________________________________________________________________________________________________________________________________________________________________________________

WordWiseMatch each definition in the left column with the correct term in the right column. Then, write the number of each term in the box below on the line under the appropriate letter. When you have filled in all the boxes, add up the numbers in each column, row, and diagonal. All the sums should be the same.DefinitionA. The process that releases energy from food molecules by producing ATP in the absence of oxygenB. The second stage of cellular respirationC. An electron carrier

D. The stage of cellular respiration in which a molecule of glucose is broken into two molecules of pyruvic acidE. The process that releases energy by breaking down food molecules in the presence of oxygen


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F. The amount of energy needed to raise the temperature of 1 gram of water 1 degree CelsiusG. A process that does not require oxygenH. A process that requires oxygenI. A series of carrier proteins in the inner membrane of mitochondria

Term

1. Krebs cycle2. anaerobic3. calorie4. electron transport chain5. cellular respiration6. fermentation7. glycolysis8. NAD+9. aerobic

Identification On the lines provided, identify which phrase describes the following processes: cellular respiration, glycolysis, lactic acid fermentation, or alcoholic fermentation.10. important in baking bread___________________________________________________________________________________________________________________________11. builds up in muscles after a few seconds of intense activity_________________________________________________________________________________________________12. requires oxygen and glucose________________________________________________________________________________________________________________________13. produces 2 ATP molecules and pyruvic acid____________________________________________________________________________________________________________14. almost the opposite process of photosynthesis__________________________________________________________________________________________________________15. the reason why runners breathe heavily after a race______________________________________________________________________________________________________

Multiple Choice On the lines provided, write the letter that best answers the question._______ 16. What is the net energy gain in glycolysis?

a. 4 molecules of ATP c. 36 molecules of ATPb. 2 molecules of ATP d. 38 molecules of ATP

_______ 17. Which of the following causes a painful, burning


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sensation in muscles after vigorous exercise?a. alcohol c. pyruvic acidb. glycolysis d. lactic acid

_______ 18. What is another name for the Krebs cycle?a. the glycolysis cycle c. the citric acid cycleb. alcoholic fermentation d. the respiration cycle

Interpreting Diagrams On the lines below, write the name of the stage of cellular respiration that corresponds with the numbers in the diagram

Vocabulary Review Hidden Word Use the clues and the words below to identify each term. Write the terms on the lines, putting one letter in each blank. When you finish, the diagonal loop will reveal a hidden word.

Anaerobic cellular respiration glycolysis NAD+calorie fermentation Krebs cycle

Clues1. electron carrier of glycolysis2. process that releases energy by breaking down food in the presence of oxygen3. process that releases energy from food molecules when no oxygen is present4. amount of energy needed to raise the temperature of 1 g of water 1°C5. stage of cellular respiration in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions6. chemical process that does not require oxygen7. process in which glucose is broken down into two molecules of pyruvic acid


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Graphic OrganizerCompare/Contrast TableCompare glycolysis, fermentation, and cellular respiration by filling in the missing information in the compare/contrast table below. If there is not enough room in the table to write your answers, write them on a separate piece of paper.


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Chapter Assessment 9

1- In cells, the energy available is food is used to make an energy-rich compound calleda- Waterb- Glucosec- ATPd- ADP

2- The first step in releasing the energy in the cell is known asa- Alcoholic fermentationb- Glycolysisc- The Kreb cycled- Electron transport

3- The process that releases energy from food in the presence of oxygen isa- Synthesisb- Cellular respirationc- ATP synthased- photosynthesis

4- Which organisms perform cellular respiration?

5- The net gain of energy from glycolysis isa- 4 ATP moleculesb- 2 ATP moleculesc- 8 ADP moleculesd- 3pyruvic acid molecules

6- Because fermentation takes place in the absence of oxygen, it is said to bea- Aerobicb- Anaerobicc- Cyclicd- Essential to oxygen production

7- The Krebs cycle takes place within thea- Chloroplastb- Nucleusc- Mitochondriond- cytoplasm

8- The electron transport chain uses the high- energy electrons from the Krebs cycle toa- Produce glucoseb- Convert ADP to ATPc- Produce acetyl- CoAd- Produce GTP

9- A total of 36 molecules of ATP are produced from 1 molecule of glucose as a result ofa- Cellular respirationb- Glycolysisc- Alcoholic fermentationd- Lactic acid fermentation

10- During heavy excericese, the buildup of lactic acid in muscle cells results ina- Alcoholic fermentationb- Oxygen dept


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c- The Calvin cycled- The Kreb cycle

11- What is a calorie? How do cells use a high- calorie molecule such as glucose?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________12- How is glucose changed during glycolysis? What products are produced as a result of glycolysis?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________13- What are the two pathways that might follow glycolysis? What factor can determine which of those pathways a cell might follow?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

14- Use formulas to write a chemical equation for cellular respiration. Label the formulas with the names of the compounds.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

15- Draw and label a mitochondrion surrounded by cytoplasm. Indicate where glycolysis, the krebs cycle, and the electron transport chain occur.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

16- How is NAD+ involved in the products of glycolysis? What happens to a cell’s NAD+ when large number of high energy electrons are produced in a short time?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

17- Which two compounds react during fermentation? Which of these compounds passes high- energy electrons to the other?___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

18- Write equations to show how lactic acid fermentation compares with alcoholic fermentation. Which reactant(s) do they hace in common?


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_____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

19- How are fermentation and cellular respiration similar? What is the main difference between their starting compounds?_____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

20- Summarize what happens during the Krebs cycle. What happens to the high- energy electrons generated during the Krebs cycle?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

21- How is ATP synthase involved in making energy available to the cell?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

22- When runners race for about 20 minutes, how do their bodies obtain energy?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

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