Name______________________________Class __________________Date ______________© Pearson Education, Inc. All rights reserved.
Photosynthesis
Section 8–1Energy and Life (pages 201–203)
This section explains where plants get the energy they need to produce food.It also describes the role of the chemical compound ATP in cellular activities.
Autotrophs and Heterotrophs (page 201)
1.Where does the energy of food originally come from?Energy in most food comes from the sun.
2.Complete the table of types of organisms.
Chemical Energy and ATP (pages 202–203)
3.What is one of the principal chemical compounds that living things
use to store energy?Adenosine triphosphate, or ATP
4.How is ATP different from ADP?ATP has three phosphate groups, while ADP has two phosphate groups.
5.Label each part of the ATP molecule illustrated below.Type Description Examples
Autotrophs Organisms that make their own food Plants
Heterotrophs Organisms that obtain energy from Animals, mushrooms
the food they eat
Adenine Ribose    3 Phosphate groups
6.When a cell has energy available, how can it store small amounts
of that energy?It can add a phosphate group to ADP molecules, producing ATP molecules.
7.When is the energy stored in ATP released?It is released when ATP is converted to ADP and a phosphate group.
TYPES OF ORGANISMS
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8.For what purpose do the characteristics of ATP make it
exceptionally useful to all types of cells?All types of cells use ATP as their basic energy
source.9.What are two ways in which cells use the energy provided by ATP?
a.Active transport
b.Movement within the cell
ATP and Glucose (page 203)
10.Why is it efficient for cells to keep only a small supply of ATP on hand? ATP is not very good for stor
ing large amounts of energy over the long term. A single sugar molecule stores more than 90 times the chemical energy of an ATP molecule.
11.Circle the letter of where cells get the energy to regenerate ATP .
a.ADP
b.phosphates
c.carbohydrates
d.
organelles
Section 8–2Photosynthesis: An Overview
(pages 204–207)This section describes what important experiments revealed about how plants grow. It also introduces the overall equation for photosynthesis and explains the roles light and chlorophyll have in the process.
Introduction (page 204)
1.What occurs in the process of photosynthesis?Plants use the energy of sunlight to convert water and carbon dioxide into high-energy carbohydrates—sugars and starches—and oxygen.Investigating Photosynthesis (pages 204–206)
2.What did Jan van Helmont conclude from his experiment?He concluded that most of the mass a plant gained had come from water, because that was the only thing he had added to the pot.
3.Circle the letter of the substance produced by the mint plant in Joseph Priestley’s experiment.a.carbon dioxide    b.water    c.air    d.oxygen
4.What did Jan Ingenhousz show?He showed that light is necessary for plants to produce oxygen.The Photosynthesis Equation
(page 206)5.Write the overall equation for photosynthesis using words.6.Write the overall equation for photosynthesis using chemical formulas.6CO 2+ 6H 2O light 6H 12O 6+ 6O 2
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Name______________________________Class __________________Date ______________Chapter 8, Photosynthesis  (continued)
7.Photosynthesis uses the energy of sunlight to convert water and
carbon dioxide into oxygen and high-energy .
Light and Pigments (page 207)
8.What does photosynthesis require in addition to water and carbon
dioxide?It requires light and chlorophyll, a molecule in chloroplasts.
9.Plants gather the sun’s energy with light-absorbing molecules
called .10.What is the principal pigment of plants? 11.Circle the letter of the regions of the visible spectrum in which
chlorophyll absorbs light very well.a.blue region
< region
Chlorophyll
pigments
sugars Reading Skill Practice
By looking at illustrations in textbooks, you can help yourself remember better what you have read. Look carefully at Figure 8–4 on page 206. What important ideas does this illustration communicate? Do your work on a separate sheet of paper.
Photosynthesis uses light energy to convert carbon dioxide and water into sugars and oxygen. This takes place in chloroplasts.Section 8–3The Reactions of Photosynthesis (pages 208–214)This section explains what happens inside chloroplasts during the process of photosynthesis.
Inside a Chloroplast (page 208)1.Chloroplasts contain saclike photosynthetic membranes called .
2.What is a granum?  A granum is a stack of thylakoids.
3.The region outside the thylakoid membranes in the chloroplasts is
called the .
4.What are the two stages of photosynthesis called?
a.Light-dependent reactions
b.Light-independent reactions, or Calvin cycle
stroma thylakoids
Light
Light-
Name______________________________Class__________________Date______________ Chapter8, Photosynthesis  (continued)
Light-Dependent Reactions(pages 210–211)
10.Circle the letter of each sentence that is true about the light-dependent
reactions.
a.They convert ADP into ATP.
b.They produce oxygen gas.
active transport
c.They convert oxygen into carbon dioxide.
d.They convert NADP+into NADPH.
11.Where do the light-dependent reactions take place?Within the thylakoid membranes
of chloroplasts
12.Circle the letter of each sentence that is true about the light-
dependent reactions.
a.High-energy electrons move through the electron transport
chain from photosystem II to photosystem I.
b.Photosynthesis begins when pigments in photosystem I absorb
light.
c.The difference in charges across the thylakoid membrane
provides the energy to make ATP.
d.Pigments in photosystem I use energy from light to reenergize
electrons.
13.How does ATP synthase produce ATP?ATP synthase allows H+ions to pass through
the thylakoid membrane. As the ions pass through, ATP synthase rotates, binding ADP and
a phosphate group together to produce ATP.
The Calvin Cycle(pages 212–213)
14.What does the Calvin cycle use to produce high-energy sugars?
The Calvin cycle uses ATP and NADPH from the light-dependent reactions to produce
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high-energy sugars.
15.Why are the reactions of the Calvin cycle also called the light-
independent reactions?The Calvin cycle does not require light.
16.Circle the letter of each statement that is true about the Calvin cycle.
a.The main products of the Calvin cycle are six carbon dioxide
molecules.
b.Carbon dioxide molecules enter the Calvin cycle from the
atmosphere.
c.Energy from ATP and high-energy electrons from NADPH are
used to convert 3-carbon molecules into similar 3-carbon
molecules.
d.The Calvin cycle uses six molecules of carbon dioxide to
produce a single 6-carbon sugar molecule.

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