Name ______________________________ Class___________________Date__________________
Cells and Energy
Study Guide A
Answer Key
SECTION 1. CHEMICAL ENERGY
AND ATP
SECTION 4. OVERVIEW OF
CELLULAR RESPIRATION
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
molecule; food molecules
high-energy; lower-energy
phosphate group
a; d; b; c
b; e
c; d
a; f
chemical energy; light energy
three; two
chemical; molecules
energy; oxygen
oxygen
mitochondria
glucose; ATP
b; c
a; c
Equation: C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O
6O 2 and C 6 H 12 O 6
6CO 2 and 6H 2 O
d
Refer to Figure 4.2 for a visual answer.
The four steps are: d, b, a, c
12. sugar
13. oxygen
14. break down
SECTION 2. OVERVIEW OF
PHOTOSYNTHESIS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
chemical energy
light energy; chemical energy
visible light
photosynthesis
stroma; grana
grana
Equation: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2
6CO 2 and 6H 2 O
6O 2 and C 6 H 12 O 6
b
require light; energy
do not require light; sugars
Refer to Figure 2.2 for a visual answer.
The four steps are: d, a, b, c
14. energy; sugars
15. green
16. independent
SECTION 5. CELLULAR
RESPIRATION IN DETAIL
1.
2.
3.
4.
5.
6.
7.
8.
9.
SECTION 6. FERMENTATION
1.
2.
3.
4.
5.
6.
ATP
electrons
hard exercise
oxygen
two
For a visual answer, refer to the lactic acid
fermentation diagram in Section 6. The
order of the four steps is: d, b, c, a
7. For a visual answer, refer to the alcoholic
fermentation diagram in Section 6. The
order of the four steps is: c, a, d, b
SECTION 3. PHOTOSYNTHESIS
IN DETAIL
1.
2.
3.
4.
5.
6.
7.
8.
9.
glucose
Pyruvate and NADH; ATP
two; four
c
c, b, a, d, e
inner
electrons; hydrogen ions
c, d, b, a
electrons
capture; transfer
molecules
ATP; NADPH
b, g, d, f, c, e, a
carbon dioxide
1 b; 2 d; A a; 3 e; 4 c
proteins
synthesizes
with no beginning or end.
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Study Guide A
i
Cells and Energy
Name ______________________________ Class___________________Date__________________
Study Guide A continued
8. Uses pyruvate and NADH = Both; Recycles
NAD+ to glycolysis = Both; Produces
Lactic Acid = Lactic acid fermentation;
Produces alcohol and carbon dioxide =
Alcoholic Fermentation.
9. cheese, yogurt
10. bread
11. carbon dioxide
12. waste product; muscles
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Study Guide A
ii
Cells and Energy
Name ______________________________ Class___________________Date__________________
Section 1: Chemical Energy and ATP
Study Guide A
KEY CONCEPT
All cells need chemical energy.
VOCABULARY
ATP
chemosynthesis
ADP
MAIN IDEA: The chemical energy used for most cell processes is carried
by ATP.
Circle the word or phrase that best completes the statement.
1. All cells use adenosine triphosphate (ATP) for energy. ATP is a molecule /
organelle that transfers energy from the breakdown of ADP / food molecules
to cell processes.
2. ATP is a high-energy / low-energy molecule that is converted into
higher-energy / lower-energy ADP when a phosphate group is removed
and energy is released.
3. ADP is converted back into ATP by the addition of a phosphate group /
food molecule.
4. Put the letter of the appropriate statement into each box of the cycle diagram
below to show the relationship between ATP and ADP.
a. High-energy adenosine triphosphate (ATP)
b. Lower-energy adenosine diphosphate (ADP)
c. Energy added from breakdown of carbon-based molecules, phosphate
added
d. Phosphate removed, energy released
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Study Guide A
1
Cells and Energy
Section 1: Chemical Energy and ATP
Name ______________________________ Class___________________Date__________________
Study Guide A continued
MAIN IDEA: Organisms break down carbon-based molecules to produce ATP.
Put the letter for each of the following six statements into the appropriate list to
identify the roles of different types of molecules when they are broken down to
make ATP.
a. molecules least likely to be broken down
b. molecules most commonly broken down
c. molecules that store most of the energy in a person’s body
d. triglyceride yields about 146 ATP
e. glucose yields about 36 ATP
f. store about the same amount of energy as carbohydrates
Type of Molecule
5.
Carbohydrates
Role in ATP Production


 4 calories per mg (4 Calories per gram)
6.
Lipids


 9 calories per mg (9 Calories per gram)
7.
Proteins


 9 calories 4 calories per mg
(4 Calories per gram)
MAIN IDEA: A few types of organisms do not need sunlight and photosynthesis
as a source of energy.
Circle the word or phrase that best completes the statement.
8. Chemosynthesis is a process by which some organisms use chemical energy /
light energy instead of chemical energy / light energy to make energy-storing
carbon-based molecules.
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Study Guide A
2
Cells and Energy
Section 1: Chemical Energy and ATP
Name ______________________________ Class___________________Date__________________
Study Guide A continued
Vocabulary Check
Fill in each blank with the word or phrase that best completes the sentence.
9. The prefix tri- means “three,” and the prefix di- means “two.” Therefore,
adenosine triphosphate (ATP) has ___________ phosphate groups, and
adenosine diphosphate (ADP) has __________________ phosphate groups.
10. The prefix chemo- means “chemical,” and synthesis comes from a Greek word
that means “to put together.” Therefore, chemosynthesis means “to put
together with chemicals.” In chemosynthesis, ______________ energy is used
to produce carbon-based ____________ that store energy.
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Study Guide A
3
Cells and Energy
Section 1: Chemical Energy and ATP
Name ______________________________ Class___________________Date__________________
Section 2: Overview of Photosynthesis
Study Guide A
KEY CONCEPT
The overall process of photosynthesis produces sugars that store chemical energy.
VOCABULARY
photosynthesis
light-dependent reactions
chlorophyll
light-independent reactions
thylakoid
MAIN IDEA: Photosynthetic organisms are producers.
Circle the word or phrase that best completes the statement.
1. Some organisms are called producers because they produce the source of
chemical energy / light energy for themselves and for other organisms.
2. Photosynthesis captures chemical energy / light energy to make sugars that
store chemical energy / light energy.
3. Chlorophyll is a molecule in chloroplasts that absorbs some of the energy in
visible light / ultraviolet light.
MAIN IDEA: Photosynthesis in plants occurs in chloroplasts.
4. Chloroplasts are membrane-bound organelles where _________ takes place
in plants.
5. Photosynthesis takes place in two parts of a chloroplast: the _________
and the _________.
6. Thylakoids are coin-shaped, membrane-enclosed compartments
inside the _________.
7. The overall process of photosynthesis can be written as a chemical equation.
Fill in the blanks in the equation below using the appropriate compound from
the box.
6CO 2
6O 2
6H 2 O
C 6 H 12 O 6
_________ + __________  ________ + ________
8. The two reactants in the photosynthesis equation are _________ and
_________.
9. The two products in the photosynthesis equation are _________ and
_________.
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Holt McDougal Biology
Study Guide A
4
Cells and Energy
Section 2: Overview of Photosynthesis
Name ______________________________ Class___________________Date__________________
Study Guide A continued
10. Why is the photosynthesis equation often written with several arrows?
a. Because many enzymes are added to the reactants to make the products.
b. Because many chemical reactions occur with the help of many enzymes.
c Because many reactants can enter into the photosynthesis reaction.
d. Because many products can be made from the photosynthesis reaction.
Circle the word or phrase that best completes the statement.
11. The light-dependent reactions require light / do not require light, and they
absorb and transfer sugars / energy.
12. The light-independent reactions require light / do not require light, and they
build sugars / energy.
13. Use the space below to sketch a chloroplast. Label the grana, thylakoids,
and stroma. Indicate where each of the following steps of the photosynthetic
process occurs.
a. Energy carried along the thylakoid membrane is transferred to molecules
that carry energy to the light-independent reactions.
b. Carbon dioxide is added to a cycle of chemical reactions to build larger
molecules.
c. A six-carbon simple sugar (usually glucose; C 6 H 12 O 6 ) is formed.
d. Energy from sunlight is absorbed and transferred along the thylakoid
membrane. Water molecules are broken down and oxygen is released.
Photosynthesis
esis
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Holt McDougal Biology
Study Guide A
5
Cells and Energy
Section 2: Overview of Photosynthesis
Name ______________________________ Class___________________Date__________________
Study Guide A continued
Vocabulary Check
Fill in each blank with the word or phrase that best completes the sentence.
14. The prefix photo- means “light,” and synthesis means “to put together.”
During photosynthesis, __________ from light is used to put together
_________.
15. The prefix chloro- means “green,” and the suffix -phyll means “leaf.”
Therefore, chlorophyll is the light-absorbing molecule that makes leaves
look _________.
16. The prefix in- means “not.” Therefore, the reactions in photosynthesis that do
not require light are called light-_________.
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Study Guide A
6
Cells and Energy
Section 2: Overview of Photosynthesis
Name ______________________________ Class___________________Date__________________
Section 3: Photosynthesis in Detail
Study Guide A
KEY CONCEPT
Photosynthesis requires a series of chemical reactions.
VOCABULARY
photosystem
ATP synthase
electron transport chain
Calvin cycle
MAIN IDEA: The first stage of photosynthesis captures and transfers energy.
1. The function of the light-dependent reactions is to __________ and
__________ energy.
2. Photosystems are groups of _______________ that capture and
transfer energy.
3. The two molecules that carry energy to the light-independent reactions are
_______ and _______.
4. Using the diagram on the next page, put each letter from the statements below
into a box to show the seven steps of the light-dependent reactions.
a. ATP synthase produces ATP.
b. Chlorophyll (in the thylakoid membrane) absorbs energy from sunlight, and
energized electrons enter the electron transport chain.
c. Energized electrons leave the electron transport chain and are used to
produce NADPH.
d. Energy from electrons in the transport chain is used to pump hydrogen ions
across the thylakoid membrane.
e. Hydrogen ions flow through a channel coupled to ATP synthase.
f. More energy is absorbed and transferred to electrons.
g. Water molecules are broken down. Oxygen is released as waste and
electrons enter chlorophyll.
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Study Guide A
7
Cells and Energy
Section 3: Photosynthesis in Detail
Name ______________________________ Class___________________Date__________________
Study Guide A continued
MAIN IDEA: The second stage of photosynthesis uses energy from the first
stage to make sugars.
5. The Calvin cycle uses energy from the light-dependent reactions to convert
_________________ into sugars.
6. Using the diagram on the next page, put the letter from each of the following
statements into the appropriate box to show the four steps of the Calvin cycle.
a. A three-carbon molecule exits the cycle. Other three-carbon molecules stay
in the cycle.
b. Carbon dioxide is added to the Calvin cycle.
c. Energy is used to convert the remaining three-carbon molecules into fivecarbon molecules.
d. Energy is used to split six-carbon molecules. Three-carbon molecules are
formed and rearranged.
e. When two three-carbon molecules have left the cycle they bond to form a
six-carbon sugar (glucose).
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
8
Cells and Energy
Section 3: Photosynthesis in Detail
Name ______________________________ Class___________________Date__________________
Study Guide A continued
1.
4.
2.
A.
3.
Vocabulary Check
Circle the word or phrase that best completes the statement.
7. The electron transport chain is a series of proteins / carbohydrates in the
thylakoid membrane along which energized electrons travel.
8. The first part of an enzyme’s name tells you about its function. All enzymes
end with the suffix -ase. Therefore, ATP synthase is an enzyme that
synthesizes / synchronizes ATP.
9. The word cycle tells you that the chemical reactions of the Calvin cycle go
from one to another with a beginning and an end / with no beginning or end.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
9
Cells and Energy
Section 3: Photosynthesis in Detail
Name ______________________________ Class___________________Date__________________
Section 4: Overview of Cellular Respiration
Study Guide A
KEY CONCEPT
The overall process of cellular respiration converts sugar into ATP using oxygen.
VOCABULARY
cellular respiration
anaerobic
aerobic
Krebs cycle
glycolysis
MAIN IDEA: Cellular respiration makes ATP by breaking down sugars.
Circle the word or phrase that best completes the statement.
1. Cellular respiration is a process that releases glucose / energy from sugars
and other carbon-based molecules to make ATP when oxygen / carbon dioxide
is present.
2. Cellular respiration is called an aerobic process, because it needs oxygen /
carbon dioxide to take place.
3. Cellular respiration takes place in the chloroplasts / mitochondria.
4. During glycolysis, one molecule of glucose / protein is split into two threecarbon molecules and two ADP / ATP are formed.
MAIN IDEA: Cellular respiration makes ATP by breaking down sugars.
5. Circle the two ways in which cellular respiration seems to be the opposite
of photosynthesis.
a. The reactions occur at either end of the chloroplast.
b. The overall chemical equations are the reverse of each other.
c. Cellular respiration breaks down sugars to make ATP, and photosynthesis
uses ATP to make sugars.
d. Cellular respiration produces oxygen, and photosynthesis produces carbon
dioxide.
6. Circle the two parts of a mitochondrion where cellular respiration takes place.
a. matrix
b stroma
c. inner mitochondrial membrane
d. outer mitochondrial membrane
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Holt McDougal Biology
Study Guide A
10
Cells and Energy
Section 4: Overview of Cellular Respiration
Name ______________________________ Class___________________Date__________________
Study Guide A continued
7. The overall process of cellular respiration can be written as a chemical
equation. Fill in the blanks in the equation below using the appropriate
compound from the box.
6CO 2
6O 2
6H 2 O
C 6 H 12 O 6
__________ + __________  ________ + ________
8. The two reactants in the cellular respiration equation are ________ and
_________.
9. The two products in the cellular respiration equation are ________ and
_________.
10. Why is the cellular respiration equation written with several arrows?
a. Because a series of products result from the reaction.
b. Because a series of reactants enter into the reaction.
c. Because a series of chemicals is added to the process.
d. Because a series of chemical reactions occurs.
11. Use the space below to sketch a mitochondrion. Label the matrix and
inner membrane. Indicate where each of the following steps of the cellular
respiration process occurs.
a. Energized electrons are passed along the electron transport chain in the
inner mitochondrial membrane.
b. Energy is transferred to the second stage of cellular respiration (the electron
transport chain).
c. A large number of ATP are formed. Oxygen picks up electrons, and water is
released as a waste product.
d. Three-carbon molecules enter the Krebs cycle and are broken down. ATP
and other energy-carrying molecules are formed. Carbon dioxide is released
as a waste product.
Cellular Respiration
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
11
Cells and Energy
Section 4: Overview of Cellular Respiration
Name ______________________________ Class___________________Date__________________
Study Guide A continued
Vocabulary Check
Fill in the blank with the word or phrase that best completes the sentence.
12. The prefix glyco- comes from a Greek word that means “sweet.” The suffix
-lysis comes from a Greek word that means “to loosen.” Therefore, during
glycolysis, a _________ is broken down (or “loosened”).
13. Glycolysis is an anaerobic process, because it takes place without
__________________.
14. During the Krebs cycle, chemical reactions _____________________ carbonbased molecules.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
12
Cells and Energy
Section 4: Overview of Cellular Respiration
Name ______________________________ Class___________________Date__________________
Section 5: Cellular Respiration in Detail
Study Guide A
KEY CONCEPT
Cellular respiration is an aerobic process with two main stages.
MAIN IDEA: Glycolysis is needed for cellular respiration.
1. The function of glycolysis is to split _______________ and produce energycarrying molecules.
2. Three molecules are formed during glycolysis when oxygen is available.
____________ and _________ are used in cellular respiration. ____________
can be used for cell processes.
3. Glycolysis results in a “net gain of two ATP molecules.” This means that
_______ ATP are used to split glucose and _________ ATP are produced.
Therefore, in the end, there are two additional ATP.
MAIN IDEA: The Krebs cycle is the first main part of cellular respiration.
4. What is the function of the Krebs cycle?
a. To produce carbon-based molecules by cellular respiration.
b. To produce carbon-based molecules by glycolysis.
c. To produce energy-carriers from the breakdown of carbon-based molecules.
d. To produce energy-carriers from the synthesis of carbon-based molecules.
5. Put the letter from each of the following statements into the appropriate box of
the cycle diagram below to summarize the six steps of the Krebs cycle.
a. Citric acid broken down, carbon dioxide released, NADH produced.
b. Citric acid formed.
c. Coenzyme A binds to two-carbon molecule; enters Krebs cycle.
d. Five-carbon molecule broken down, carbon dioxide released, NADH and
ATP produced.
e. Four-carbon molecule rearranged, NADH and FADH 2 produced.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
13
Cells and Energy
Section 5: Cellular Respiration in Detail
Name ______________________________ Class___________________Date__________________
Study Guide A continued
Pyruvate broken
down
MAIN IDEA: The electron transport chain is the second main part of cellular
respiration.
Circle the word or phrase that best completes the statement.
6. The electron transport chain in cellular respiration is located on the
inner / outer mitochondrial membrane.
7. The electron transport chain uses energy from electrons / protons to pump
oxygen ions / hydrogen ions across the membrane, so that the ions can flow
back through ATP synthase to produce ATP.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
14
Cells and Energy
Section 5: Cellular Respiration in Detail
Name ______________________________ Class___________________Date__________________
Study Guide A continued
8. Use the statements below to fill in the sequence showing the four steps of the
electron transport chain.
a. Oxygen picks up electrons from the transport chain and hydrogen ions;
water is produced and released.
b. Hydrogen ions flow through ATP synthase; ATP is produced.
c. High-energy electrons removed from NADH and FADH 2 by proteins in the
transport chain.
d. Energy from the electrons used to pump hydrogen ions across the inner
mitochondrial membrane.
9. Cellular respiration can only operate when oxygen is available to pick up
____________ at the end of the electron transport chain.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
15
Cells and Energy
Section 5: Cellular Respiration in Detail
Name ______________________________ Class___________________Date__________________
Section 6: Fermentation
Study Guide A
KEY CONCEPT
Fermentation allows the production of a small amount of ATP without oxygen.
VOCABULARY
fermentation
lactic acid
MAIN IDEA: Fermentation allows glycolysis to continue.
1. Fermentation is important, because it allows glycolysis to continue making
_________ when oxygen is unavailable for cellular respiration.
2. Fermentation removes ____________ from NADH and recycles NAD+ to
glycolysis.
3. Fermentation takes place in your muscle cells during
_____________________________, when not enough oxygen is available.
4. Fermentation is an anaerobic process, because it occurs without
_______________.
5. Fermentation is involved in the production of ATP by allowing glycolysis to
take place. Glycolysis yields _______________ net ATP.
6. In the space below, draw the process of lactic acid fermentation and label it
with the statements listed.
a. NAD+ is recycled to glycolysis.
b. NADH is used to convert pyruvate into lactic acid.
c. NADH is changed into NAD+.
d. Pyruvate and glycolysis enter fermentation.
Lactic Acid Fermentation
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
16
Cells and Energy
Section 6: Fermentation
Name ______________________________ Class___________________Date__________________
Study Guide A continued
MAIN IDEA: Fermentation and its products are important in several ways.
7. In the space below, draw the process of alcoholic fermentation and label it
with the statements listed.
a. NADH is used to convert pyruvate into alcohol and carbon dioxide.
b. NAD+ is recycled to glycolysis.
c. Pyruvate and glycolysis enter fermentation.
d. NADH is changed into NAD+ .
Alcoholic Fermentation
8. Place a check mark in the appropriate boxes below to show how lactic acid
fermentation and alcoholic fermentation are similar and how they are different.
Lactic Acid
Fermentation
Alcoholic
Fermentation
Both
Uses pyruvate and NADH
Recycles NAD+ to
glycolysis
Produces lactic acid
Produces alcohol and
carbon dioxide
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
Study Guide A
17
Cells and Energy
Section 6: Fermentation
Name ______________________________ Class___________________Date__________________
Study Guide A continued
9. Name one commercial use of lactic acid fermentation. ________________
10. Name one commercial use of alcoholic fermentation. ________________
Vocabulary Check
Circle the word or phrase that best completes the statement.
11. The term fermentation is based on a word that means “to bubble.” This
meaning is related to the fermentation process, because bubbles of carbon
dioxide / oxygen are produced during alcoholic fermentation.
12. Lactic acid is the three-carbon reactant / waste product of lactic acid
fermentation. It causes a burning feeling in your muscles / blood vessels during
exercise
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Study Guide A
18
Cells and Energy
Section 6: Fermentation