Unformatted text preview: CHAPTER 9 Cellular Respiration
and Fermentation Connect to the Big Idea
Use the micrograph of the mitochondria to
help students start thinking about the concepts of cellular respiration and fermentation. First, activate prior knowledge by asking them if
they know what mitochondria are and what their
function is. (cellular organelles that convert the
chemical energy stored in food into chemical compounds that cells can use) Cellular Basis of Life
Q: How do organisms obtain energy? Now ask students what links the cereal they had for
breakfast with the mitochondria in the micrograph.
(energy) Point out that food, like this morning’s
cereal, contains molecules that the mitochondria can
use to make energy available to cells. Then, ask why
cells need energy. (to carry out cell activities) Ask students to anticipate the answer to the question, How
do organisms obtain energy?
Have students read over the
Chapter Mystery and predict how
sperm whales can stay active for
so long on only one breath. To make their predictions, suggest students think about how cells obtain
and release the energy whales need to dive. Use
their predictions to help them start connecting the
Chapter Mystery to the Big Idea of the Cellular Basis
of Life. Have students preview the chapter
vocabulary terms using the Flash Cards. Chapter 9 NATIONAL SCIENCE EDUCATION STANDARDS • Flash Cards 248 UNIFYING CONCEPTS AND PROCESSES I, III, V
0001_Bio10_se_Ch09_CO.indd 1 CONTENT B.3, C.1.a, C.1.b, C.5.a, C.5.b, C.5.c, C.5.d, F.1, G.1
INQUIRY A.1.b, A.1.c, A.1.f, A.2.a, A.2.d Understanding by Design
A cell is the basic unit of life; the processes that occur at the cellular level provide the
energy and basic structure organisms need to survive. Students explore this Enduring
Understanding in Chapter 9 by examining the processes of cellular respiration and
fermentation. As shown in the graphic organizer at the right, the Big Idea, Essential
Question, and lesson-level Guiding Questions help frame their exploration.
PERFORMANCE GOALS In Chapter 9, students will learn how cellular respiration and fermentation provide
organisms with the energy they need to survive. Students will show this understanding by interpreting multiple, detailed ﬁgures. They will also practice their data analysis
skills by collecting and interpreting data on the byproducts of cellular respiration. At
the end of the chapter, students will transfer their knowledge by keeping an exercise
journal and relating the entries to cellular respiration and fermentation. 248 Chapter 9 6/2/09 6:44:14 PM INSIDE: DIVING WITHOUT
A BREATH • 9.1 Cellular Respiration: An Overview
• 9.2 The Process of Cellular Respiration
• 9.3 Fermentation Mitochondria (red) and smooth
endoplasmic reticulum (yellow)
in an ovarian cell (SEM 75,000×). Everyone is familiar with the sensation
of being “out of breath.” Just a few
minutes of vigorous exercise can have
humans hufﬁng and pufﬁng for air. But
what if you couldn’t get air? What if
you were asked to hold your breath and
exercise? Before too long, you’d pass
out due to a lack of oxygen. This may
seem like a silly thought experiment,
but there are animals that exercise
without breathing and without passing
out all the time—whales. Unlike most
animals that live their entire lives in
water, whales still rely on oxygen
obtained from air when they surface.
Amazingly, sperm whales routinely
stay underwater for 45 minutes or
more when diving. Some scientists
suspect that they can stay underwater
for 90 minutes! How is that possible?
Diving takes a lot of energy. How do
whales stay active for so long on only
one breath? As you read this chapter,
look for clues. Then, solve the mystery.
Never Stop Exploring Your World.
Learning about whales and their
extraordinary ability to hold their
breaths is just the beginning. Take a
video ﬁeld trip with the ecogeeks of
Untamed Science to see where this
mystery leads. Extend your reach by using
these and other digital assets offered at
CHAPTER MYSTERY Discover how the processes of cellular respiration
and fermentation can affect the behavior and function of an entire organism—in this case, how often
whales need to breathe.
UNTAMED SCIENCE Dive below the ocean surface to explore how marine
mammals can survive on a single breath for as long
as they do. ART IN MOTION An animated diagram highlights the relationship
between photosynthesis and cellular respiration.
INTERACTIVE ART In this short animation, students watch how glucose
is broken down and energy is transferred during the
process of cellular respiration.
• Untamed Science Video ART REVIEW • Chapter Mystery
Cellular Respiration and Fermentation 249 Students explore the details of electron transport and
TUTOR TUBE 0001_Bio10_se_Ch09_CO.indd 249 Chapter 9
Cellular Basis of Life Chapter 9 EQ:
How do organisms
obtain energy? 6/9/09 1:36:31 PM 9.1 GQ: Why do most organisms undergo the
process of cellular respiration? This short, online tutorial provides extra help on the
electron transport chain and ATP production.
DATA ANALYSIS Students analyze data to learn more about lactic acid
and exercise. 9.2 GQ: How do cells release energy from
food in the presence of oxygen?
9.3 GQ: How do cells release energy from
food without oxygen? Cellular Respiration and Fermentation 249 CHAPTER 9 What’s Online LESSON 9.1 Cellular Respiration:
An Overview Getting Started
9.1.1 Explain where organisms get the energy they
need for life processes.
9.1.2 Define cellular respiration. Key Questions 9.1.3 Compare photosynthesis and cellular
respiration. Where do organisms get
What is cellular respiration? Student Resources
Study Workbooks A and B, 9.1 Worksheets
Spanish Study Workbook, 9.1 Worksheets
Lab Manual B, 9.1 Data Analysis Worksheet What is the relationship
between photosynthesis and
cellular respiration? Vocabulary
calorie • cellular respiration •
aerobic • anaerobic Taking Notes Lesson Overview • Lesson Notes
• Activity: Art in Motion • Assessment: SelfTest, Lesson Assessment
For corresponding lesson in the
Foundation Edition, see pages 212–215. Activate Prior Knowledge
Write the term cellular respiration on the board.
Then, make a T-Chart below it. Label one column
Facts and the other Questions. Have each student
come up to the board and write either a fact they
know or a question they have about cellular respiration. Discuss the T-Chart as a class. Answer any questions that students will need to know before reading
the lesson. Preview Visuals Before you
read, study Figure 9–2 on
page 252. Make a list of questions that you have about the diagram. As you read, write down
the answers to the questions. BUILD Vocabulary
PREFIXES The preﬁx macromeans “large” or “elongated.”
Macromolecules are made
up of many smaller molecular
proteins, and lipids are
found in living things. Study Wkbks A/B, Appendix S30, T-Chart.
Transparencies, GO15. THINK ABOUT IT When you are hungry, how do you feel? If you
are like most people, you might feel sluggish, a little dizzy, and—above
all—weak. Weakness is a feeling triggered by a lack of energy. You feel
weak when you are hungry because food serves as a source of energy.
Weakness is your body’s way of telling you that your energy supplies
are low. But how does food get converted into a usable form of energy?
Car engines have to burn gasoline in order to release its energy. Do our
bodies burn food the way a car burns gasoline, or is there something
more to it? Chemical Energy and Food
Where do organisms get energy? Food provides living things with the chemical building blocks they need
to grow and reproduce. Recall that some organisms, such as plants, are
autotrophs, meaning that they make their own food through photosynthesis. Other organisms are heterotrophs, meaning that they rely on
other organisms for food. For all organisms, food molecules contain
chemical energy that is released when their chemical bonds are broken.
Organisms get the energy they need from food.
How much energy is actually present in food? Quite a lot, although
it varies with the type of food. Energy stored in food is expressed in
units of calories. A calorie is the amount of energy needed to raise the
temperature of 1 gram of water 1 degree Celsius. The Calorie (capital
C) that is used on food labels is a kilocalorie, or 1000 calories. Cells can
use all sorts of molecules for food, including fats, proteins, and carbohydrates. The energy stored in each of these macromolecules varies
because their chemical structures, and therefore their energy-storing
bonds, differ. For example, 1 gram of the sugar glucose releases 3811
calories of heat energy when it is burned. By contrast, 1 gram of the triglyceride fats found in beef releases 8893 calories of heat energy when
its bonds are broken. In general, carbohydrates and proteins contain
approximately 4000 calories (4 Calories) of energy per gram, while fats
contain approximately 9000 calories (9 Calories) per gram.
Cells, of course, don’t simply burn food and release energy as heat.
Instead, they break down food molecules gradually, capturing a little
bit of chemical energy at key steps. This enables cells to use the energy
stored in the chemical bonds of foods like glucose to produce compounds such as ATP that directly power the activities of the cell. NATIONAL SCIENCE EDUCATION STANDARDS
Lesson 9.1 250 • Lesson Overview • Lesson Notes UNIFYING CONCEPTS AND PROCESSES I, V
0001_Bio10_se_Ch09_S1.indd 1 CONTENT B.3, C.1.a, C.1.b, C.5.a, C.5.c, C.5.d
INQUIRY A.1.c, A.2.a, A.2.d Teach for Understanding
ENDURING UNDERSTANDING A cell is the basic unit of life; the processes that occur at the cellular level provide the energy and basic structure organisms need to survive.
GUIDING QUESTION Why do most organisms undergo the process of cellular respiration?
EVIDENCE OF UNDERSTANDING At the end of the lesson, have students complete this assessment to show they understand the importance of cellular respiration for
life on Earth. Have students make a case for cellular respiration. Ask them to write
a short persuasive argument that explains why cellular respiration is an important
process on an individual organism level as well as on a global scale. 250 Chapter 9 • Lesson 1 6/2/09 6:46:28 PM You Are What You Eat Food Organisms get energy from the
food they eat, but the energy contained in foods varies greatly. Most
foods contain a combination of
proteins, carbohydrates, and fats.
One gram of protein or a carbohydrate such as glucose contains
roughly 4 Calories. One gram of fat,
however, contains about 9 Calories.
The accompanying table shows the
approximate composition of one
serving of some common foods.
1. Interpret Data Per serving, which
of the foods included in the table
has the most protein? Which has
the most carbohydrates? Which
has the most fat? Protein (g) Carbohydrate (g) Fat (g) Apple, 1 medium 0 22 0 Bacon, 2 slices 5 0 6 Chocolate, 1 bar 3 23 13
9 12 0 2% milk, 1 cup 8 12 5 Potato chips, 15 chips 2 14 10 11 3 1 Eggs, 2 whole Skinless roasted turkey,
3 slices Lead a Discussion Make sure students understand the overall chemical
summary for cellular respiration. Reinforce that the
bolded reactions shown are simpliﬁcations, or summations, of many sub-reactions. Have students verify
that the reaction shown is balanced by counting the
molecules of each element on the right and left sides
of the reaction. 2. Calculate Approximately how many more Calories are there in 2 slices of bacon than there are in 3 slices
of roasted turkey? Why is there a difference? DIFFERENTIATED INSTRUCTION 3. Calculate Walking at a moderate pace consumes around 300 Calories per hour. At that rate, how many
minutes would you have to walk to burn the Calories
in one chocolate bar? (Hint: Start by calculating the
number of Calories consumed per minute by walking.) Overview of Cellular Respiration
What is cellular respiration?
If oxygen is available, organisms can obtain energy from food by a
Cellular respiration is the
process called cellular respiration.
process that releases energy from food in the presence of oxygen.
Although cellular respiration involves dozens of separate reactions,
an overall chemical summary of the process is remarkably simple: In Words:
Oxygen + Glucose L1 Struggling Students Write the word form of
the cellular respiration summary on the board. Then,
read it aloud, pointing to each word and reaction
symbol as you read. For example, you might say,
“oxygen and glucose are converted into carbon dioxide and water and energy.” As you say oxygen, point
to the word; as you say and, point to the plus sign.
Then, write the symbol form of the summary below
it. Draw lines from each chemical formula to its corresponding name in the word form of the summary. ELL In Symbols:
6O2 + C6H12O6 LESSON 9.1 Teach Composition of Some Common Foods 6CO2 + 6H2O + Energy Focus on ELL:
Build Background BEGINNING AND INTERMEDIATE SPEAKERS
Carbon dioxide + Water + Energy As you can see, cellular respiration requires oxygen and a food molecule
such as glucose, and it gives off carbon dioxide, water, and energy. Do
not be misled, however, by the simplicity of this equation. If cellular
respiration took place in just one step, all of the energy from glucose
would be released at once, and most of it would be lost in the form
of light and heat. Clearly, a living cell has to control that energy. It
can’t simply start a ﬁre—the cell has to release the explosive chemical
energy in food molecules a little bit at a time. The cell needs to ﬁnd a
way to trap those little bits of energy by using them to make ATP. FIGURE 9 –1 A Controlled Release Cellular respiration involves a series
of controlled reactions that slowly
release the energy stored in food. If
the energy were to be released too
suddenly, most of it would be lost in
the forms of light and heat—just as it
is when a marshmallow catches ﬁre. In Your Notebook Do plants undergo cellular respiration? What Distribute copies of a BKWL Chart to your
students. Then, show students a short animation,
video, or several drawings of the process of
cellular respiration. Have them take notes on the
visuals in the build background column. Write
the words obtain, release, extract, respiration,
and energy on the board. Have them copy the
words and define each in the build background
column. Then, have students fill out the K and
W columns of the chart. As students read the
lesson, have them fill in the L column. organelle(s) do they have that helps you determine the answer?
Cellular Respiration and Fermentation 251 0001_Bio10_se_Ch09_S1.indd 2 PURPOSE Students will examine and
interpret data to find how the energy
content in foods varies.
PLANNING Have a few of the foods listed in the table on hand, and display
them for students before they do the
activity. Ask students to predict which
of the foods contain the most Calories,
and have them explain their reasoning. Study Wkbks A/B, Appendix S27, BKWL Chart.
Transparencies, GO12. 6/2/09 6:46:33 PM ANSWERS
1. Eggs have the most protein; chocolate has the most carbohydrates; chocolate has the most fat.
2. There are approximately 9 more Calories in 2 slices of bacon than in
3 slices of roast turkey. The primary
difference is that the bacon contains
so much more fat than the turkey.
3. a little over 44 minutes Answers
IN YOUR NOTEBOOK Yes; they contain mitochondria. Cellular Respiration and Fermentation 251 LESSON 9.1 Glucose Teach Glycolysis continued Energy Use Visuals
Use Figure 9–2 to talk about the overall process of
cellular respiration. Start by helping students make
the connection between this visual and the chemical
summary equations from the previous page. Point
out where and how glucose and oxygen are used
during the process and that water, carbon dioxide,
and energy are released. Make sure students understand that cellular respiration can be divided into
three basic stages. Tell them that they will learn more
detailed information about each of these stages in
later lessons. DIFFERENTIATED INSTRUCTION
L1 Struggling Students Have students read the
section, Stages of Cellular Respiration, in the text
and look carefully at Figure 9–2. As a class, discuss
the ﬁrst pictured stage, glycolysis. Then, have students write a one-sentence summary of the discussion. For example, students might write, “During
glycolysis, glucose is broken down into pyruvic acid
and energy is released.” Then, discuss and summarize each of the next two stages. To help students answer the question,
remind them that whales need to surface to breathe air. Make the connection between aerobic pathways and the whale’s
breathing. Ask them to speculate on how long the
breath might last and how the whale might obtain
energy once that air runs out. Students can go online
to Biology.com to gather their evidence. Krebs Cycle
Energy O2 H 2O FIGURE 9 –2 The Stages of Cellular Respiration There are three stages
to cellular respiration: glycolysis,
the Krebs cycle, and the electron
transport chain. Interpret Visuals
Which stage(s) of cellular respiration
occur in the mitochondrion? If whales remain
45 minutes or more,
do you think they
rely primarily on
aerobic or anaerobic
FIGURE 9–2 the Krebs cycle and the electron transport chain
IN YOUR NOTEBOOK Flowcharts should accurately
show the connections between glycolysis, the Krebs
cycle, and the electron transport chain. 252 Chapter 9 • Lesson 1 Oxygen and Energy Oxygen is required at the very end of
the electron transport chain. Any time a cell’s demand for energy
increases, its use of oxygen increases, too. As you know, the word
respiration is often used as a synonym for breathing. This is why we
have used the term cellular respiration to refer to energy-releasing
pathways within the cell. The double meaning of respiration points
out a crucial connection between cells and organisms: Most of the
energy-releasing pathways within cells require oxygen, and that is the
reason we need to breathe, to respire.
Pathways of cellular respiration that require oxygen are said to
be aerobic (“in air”). The Krebs cycle and electron transport chain
are both aerobic processes. Even though the Krebs cycle does not
directly require oxygen, it is classiﬁed as an aerobic process because
it cannot run without the oxygen-requiring electron transport
chain. Glycolysis, however, does not directly require oxygen, nor
does it rely on an oxygen-requiring process to run. Glycolysis is
therefore said to be anaerobic (“without air”). Even though glycolysis is anaerobic, it is considered part of cellular respiration because
its ﬁnal products are key reactants for the aerobic stages.
Recall that mitochondria are structures in the cell that convert
chemical energy stored in food to usable energy for the cell.
Glycolysis actually occurs in the cytoplasm of a cell, but the Krebs
cycle and electron transport chain, which generate the majority of
ATP during cellular respiration, take place inside the mitochondria.
If oxygen is not present, another anaerobic pathway, known
as fermentation, makes it possible for the cell to keep glycolysis running, generating ATP to power cellular activity. You will learn more
about fermentation later in this chapter.
In Your Notebook Make a ﬂowchart that shows the different
steps of cellular respiration. Address Misconceptions
Cellular Respiration v. Respiration Some of your students may have difﬁculty distinguishing between
the concepts of cellular respiration and respiration
as breathing. Have students read the ﬁrst paragraph
of the Oxygen and Energy section, research the
connection between the two processes, and make
a poster for the classroom wall that graphically
shows the relationship. Stages of Cellular Respiration Cellular respiration captures the
energy from food in three main stages—glycolysis, the Krebs cycle,
and the electron transport chain. Alt...
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