Biology II 1
Chapter 9 Cellular Respiration
Tabla de contenido
Summary ................................................................................................................................................. 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
Biology II 2
Chapter 9 Cellular Respiration
Summary
9–1 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 + Energy
oxygen + glucose ➞ carbon + water + energy dioxide
There 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+ acid
Lactic 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 Transport
When 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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Chapter 9 Cellular Respiration
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 Review
Matching In the space provided, write the letter of the definition that best matches each
term.
_____ 1. calorie
c. requires oxygen
_____ 2. glycolysis
d. process in which one molecule of
_____ 3. cellular respiration
glucose is broken
_____ 4. NAD+
in half, producing two molecules of
_____ 5. fermentation
pyruvic acid
_____ 6. anaerobic
e. does not require oxygen
_____ 7. Aerobic
f. amount of energy needed to raise 1 gram
of water 1
a. electron carrier
degree Celsius
b. pathway that releases energy from food
g. process that releases energy by breaking
in the
down food
absence of oxygen
molecules 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? __________________________________________________________
Biology II 4
Chapter 9 Cellular Respiration
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 Mitochondrion
In 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 Overview
Cellular 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 cycle
1_______________________
2_______________________
3_______________________
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Chapter 9 Cellular Respiration
45-
_______________________
_______________________
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 Fermentation
Glycolysis 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
1Describe the process of cellular respiration.
___________________________________________________________________________
___________________________________________________________________________
2What are the products of glycolysis?
Biology II 6
Chapter 9 Cellular Respiration
___________________________________________________________________________
___________________________________________________________________________
3What is a calorie? A Calorie?
___________________________________________________________________________
___________________________________________________________________________
4How is the function of NAD+ similar to that to NADP+?
___________________________________________________________________________
___________________________________________________________________________
5How 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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Chapter 9 Cellular Respiration
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 -- Lactobacillus
When 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.
Biology II 8
Chapter 9 Cellular Respiration
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 9-1
Reviewing Key Concepts
Completion 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?
___________________________________________________________________________
___________________________________________________________________________
Biology II 9
Chapter 9 Cellular Respiration
7. How does fermentation allow the production of ATP to continue?
___________________________________________________________________________
___________________________________________________________________________
Reviewing Key Skills
Labeling 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 Cycle
If 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
Biology II 10
Chapter 9 Cellular Respiration
Electron Transport Chain
The 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 Photosynthesis
Cellular 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
Biology II 11
Chapter 9 Cellular Respiration
Use the table to answer the questions.
1. Which process releases energy for the cell? Circle the correct answer.
cellular respiration
photosynthesis
2. For which reaction is 6CO2 _ 6H2O ➝ C6H12O6 + 6O2 the correct equation? Circle the
correct answer.
cellular respiration
photosynthesis
3. How do the products of photosynthesis compare to the reactants of cellular respiration?
___________________________________________________________________________
___________________________________________________________________________
9-2 The Krebs Cycle and Electron Transport
1What happens to pyruvic acid during the Krebs cycle?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
2How does the electron transport chain use the high- energy electrons from the Kreb
cycle?
___________________________________________________________________________
___________________________________________________________________________
__________________________________________________________________________
3Why is cellular respiration considered to be much more efficient than glycolysis
alone?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
4How many molecules of ATP are produced in the entire breakdown of glucose?
___________________________________________________________________________
___________________________________________________________________________
5Compare the energy flow in photosynthesis to the energy flow in cellular respiration.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
6How is the chemical energy in glucose similar to money in a savings account?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Biology II 12
Chapter 9 Cellular Respiration
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? _________________________________________
Biology II 13
Chapter 9 Cellular Respiration
___________________________________________________________________________
___________________________________________________________________________
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.
Biology II 14
Chapter 9 Cellular Respiration
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?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Biology II 15
Chapter 9 Cellular Respiration
9-2 Section Reviewing Key Concepts
Short 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 Skills
Identification 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 food
9. 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.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
WordWise
Match 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.
D. The stage of cellular respiration in
Definition
A. The process that releases energy from
which a molecule of glucose is broken into
food molecules by producing ATP in the
two molecules of pyruvic acid
absence of oxygen
E. The process that releases energy by
B. The second stage of cellular respiration
breaking down food molecules in the
C. An electron carrier
presence of oxygen
Biology II 16
Chapter 9 Cellular Respiration
F. The amount of energy needed to raise
the temperature of 1 gram of water 1
degree Celsius
G. A process that does not require oxygen
H. A process that requires oxygen
I. A series of carrier proteins in the inner
membrane of mitochondria
Term
1. Krebs cycle
2. anaerobic
3. calorie
4. electron transport chain
5. cellular respiration
6. fermentation
7. glycolysis
8. 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 ATP
b. 2 molecules of ATP
d. 38 molecules of ATP
_______ 17. Which of the following causes a painful, burning
Biology II 17
Chapter 9 Cellular Respiration
sensation in muscles after vigorous exercise?
a. alcohol
c. pyruvic acid
b. glycolysis
d. lactic acid
_______ 18. What is another name for the Krebs cycle?
a. the glycolysis cycle
c. the citric acid cycle
b. 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
calorie
fermentation
glycolysis
Krebs cycle
NAD+
Clues
1. electron carrier of glycolysis
2. process that releases energy by breaking down food in the presence of oxygen
3. process that releases energy from food molecules when no oxygen is present
4. amount of energy needed to raise the temperature of 1 g of water 1°C
5. stage of cellular respiration in which pyruvic acid is broken down into carbon dioxide in a
series of energy-extracting reactions
6. chemical process that does not require oxygen
7. process in which glucose is broken down into two molecules of pyruvic acid
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Chapter 9 Cellular Respiration
Graphic Organizer
Compare/Contrast Table
Compare 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.
Biology II 19
Chapter 9 Cellular Respiration
Chapter Assessment 9
1abcd2abcd3abcd4-
5abcd6abcd7abcd8abcd9abcd10ab-
In cells, the energy available is food is used to make an energy-rich compound called
Water
Glucose
ATP
ADP
The first step in releasing the energy in the cell is known as
Alcoholic fermentation
Glycolysis
The Kreb cycle
Electron transport
The process that releases energy from food in the presence of oxygen is
Synthesis
Cellular respiration
ATP synthase
photosynthesis
Which organisms perform cellular respiration?
The net gain of energy from glycolysis is
4 ATP molecules
2 ATP molecules
8 ADP molecules
3pyruvic acid molecules
Because fermentation takes place in the absence of oxygen, it is said to be
Aerobic
Anaerobic
Cyclic
Essential to oxygen production
The Krebs cycle takes place within the
Chloroplast
Nucleus
Mitochondrion
cytoplasm
The electron transport chain uses the high- energy electrons from the Krebs cycle to
Produce glucose
Convert ADP to ATP
Produce acetyl- CoA
Produce GTP
A total of 36 molecules of ATP are produced from 1 molecule of glucose as a result of
Cellular respiration
Glycolysis
Alcoholic fermentation
Lactic acid fermentation
During heavy excericese, the buildup of lactic acid in muscle cells results in
Alcoholic fermentation
Oxygen dept
Biology II 20
Chapter 9 Cellular Respiration
c- The Calvin cycle
d- The Kreb cycle
11What is a calorie? How do cells use a high- calorie molecule such as glucose?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
12How is glucose changed during glycolysis? What products are produced as a result of
glycolysis?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
13What are the two pathways that might follow glycolysis? What factor can determine
which of those pathways a cell might follow?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
14Use formulas to write a chemical equation for cellular respiration. Label the formulas
with the names of the compounds.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
15Draw and label a mitochondrion surrounded by cytoplasm. Indicate where glycolysis,
the krebs cycle, and the electron transport chain occur.
___________________________________________________________________________
___________________________________________________________________________
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16How 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?
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17Which two compounds react during fermentation? Which of these compounds passes
high- energy electrons to the other?
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18Write equations to show how lactic acid fermentation compares with alcoholic
fermentation. Which reactant(s) do they hace in common?
Biology II 21
Chapter 9 Cellular Respiration
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19How are fermentation and cellular respiration similar? What is the main difference
between their starting compounds?
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20Summarize what happens during the Krebs cycle. What happens to the high- energy
electrons generated during the Krebs cycle?
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21How is ATP synthase involved in making energy available to the cell?
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22When runners race for about 20 minutes, how do their bodies obtain energy?
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