Objective
Students will be able to verbally list the
reactants and products of
Photosynthesis by the end of the
period.
Photosynthesis
Chapter 8
Ag Biology
Ms. Prescott
8-1 Energy and Life
8-2 Photosynthesis
8-3 Light-Dependent
Reactions & Calvin Cycle
8-1
Energy and Life
Saving for a Rainy Day
Suppose you earned extra money by having a parttime job. At first, you might be tempted to spend
all of the money, but then you decide to open a
bank account.
1. What are the benefits of having a bank account?
2. What do you have to do if you need some of this
money?
3. What might your body do when it has more
energy than it needs to carry out its activities?
4. What does your body do when it needs energy?
8-1 Vocabulary
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Autotrophorganism that can capture energy from
sunlight or chemicals and use it to produce
its own food from inorganic compounds;
also called a producer
Heterotrophorganism that obtains energy from the
foods it consumes; also called a consumer
Adenosine triphosphate (ATP) –
one of the principal chemical compounds
that living things use to store energy.
8-1 Energy and Life
1. Autotrophs and Heterotrophs
a. Autotrophs: organisms, like plants, that
use light energy from the sun to produce
their own food Because plants can “manufacture” their
own energy directly, they are self-sufficient.
b. Heterotrophs: organisms that obtain
energy from foods they consume
All other forms of life, such as humans, animals, insects and even
bacteria, depend on other living things for sustenance.
8-1 Energy and Life
2. Chemical Energy and ATP
a. The cell’s activities are powered by
chemical fuels
i.
ATP is a compound that living things use to store
energy
ii. ADP is the compound used to store energy in cells
i. It can hold one more phosphate when energy is
needed
ii. Energy is released when ATP converts to ADP
Adenine
Ribose
3 Phosphate groups
Figure 8-3 Comparison of ADP and
ATP to a Battery
Section 8-1
ADP
ATP
Energy
Adenosine diphosphate (ADP) + Phosphate
Partially
charged
battery
Go to
Section:
Energy
Adenosine triphosphate (ATP)
Fully
charged
battery
Figure 8-3 Comparison of ADP and
ATP to a Battery
Section 8-1
ADP
ATP
Energy
Adenosine diphosphate (ADP) + Phosphate
Partially
charged
battery
Go to
Section:
Energy
Adenosine triphosphate (ATP)
Fully
charged
battery
8-1 Energy and Life
b. ATP and Glucose
a. Most cells only have a small amount of ATP,
enough to last for only a few seconds of
activity because it is not good for storing
large amounts of energy for long periods of
time
a. Glucose stores more than 90 times the
energy of a molecule of ATP
b. Cells can regenerate ATP from ADP as
needed by using the energy in
carbohydrates, like glucose
8-2 / 8-3
Photosynthesis:
An Overview
8-2 Interest Grabber Trapping Energy
Have you ever used a solar-powered calculator? No
matter where you go, as long as you have a light
source, the calculator works. You never have to put
batteries in it.
1. A solar-powered calculator uses solar cells that are found in
rows along the top of the calculator. Into what kind of energy
is the light energy converted so that the calculator works?
2. Recall that plants use light energy from the sun to make
food. Into what kind of energy is the light energy converted
by plants?
3. Most plants, no matter what size or shape they are, have
some parts that are green. Which parts of a plant are
usually green?
4. What does the green color have to do with the plant’s
ability to convert light energy into the energy found in the
food it makes?
8-2/8-3 Vocabulary
Photosynthesisprocess by which plants and some other
organisms use light energy to power chemical
reactions that convert water and carbon dioxide
into oxygen and high-energy carbohydrates such
as sugar and starches.
Pigmentlight-absorbing colored molecule
Chlorophyllprincipal pigment of plants and other
photosynthetic organisms; capture light energy
ThylakoidSaclike body in chloroplasts made of
photosynthetic membranes that contain
photosystems.
8-2/8-3 Photosynthesis Notes
1. The Photosynthesis Equation
a. Photosynthesis uses the energy of sunlight
to convert carbon dioxide and water into
high-energy sugar and oxygen
i.
6C02 + 6H2O  C6H12O6 +602
 Chemically:
Green Plant
6C02 + 6H2O
( Carbon dioxide + Water
Light Energy
C6H12O6 +602
Sugar + Oxygen)
 Written:
“Six molecules of carbon dioxide plus six molecules of water combine in the
presence of a green plant and light energy to form one molecule of sugar and
six molecules of oxygen.”
8-2/8-3 Photosynthesis
2. Light and Pigments
a. In addition to water and carbon dioxide,
photosynthesis requires light and chlorophyll, a
molecule in chloroplasts
b. Plants gather the sun’s energy with lightabsorbing molecules called pigments
a. The principal pigment is chlorophyll
b. Energy molecules released from the reaction
are ATP & NADPH
Photosynthesis: Reactants and
Products
Section 8-2
Light Energy
Chloroplast
CO2 + H2O
Go to
Section:
Sugars + O2
Figure 8-5 Chlorophyll Light
Absorption
Section 8-2
Absorption of Light by
Chlorophyll a and Chlorophyll b
Chlorophyll b
Chlorophyll a
V
Go to
Section:
B
G
YO
R
8-2/8-3 Photosynthesis
3. Inside a Chloroplast
a. Chloroplasts contain saclike
photosynthetic membranes call
thylakoids arranged in stacks
b. The thylakoids contain clusters of
chlorophyll and other pigments and
protein known as photosystems
c. There are two stages to photosynthesis
used to make glucose
i.
Light-dependent reactions: take place in the
thylakoid
ii. Light-independent reactions (Calvin Cycle): takes
place in the stroma, outside the thylakoid
8-3
Light-Dependent Reactions
& Calvin Cycle
8-3 Vocabulary
Thylakoidsaclike body in chloroplasts made of
photosynthetic membranes that contain
photosystems
Stromaregion outside the thylakoid membranes in
chloroplasts
NADP+ (Nicotinamide adenine
dinucleotide) –
one of the carrier molecules that transfer highenergy electrons from chlorophyll to other
molecules.
8-3 Vocabulary
Light-dependent reactionreactions of photosynthesis that use energy from
light to produce ATP and NADPH
ATP synthaselarge protein that uses energy from H+ ions to
bind ADP and a phosphate group together to
produce ATP
Calvin Cyclereactions of photosynthesis in which energy from
ATP and NADPH is used to build high-energy
compounds such as sugars.
8-3 Light-dependent Reactions
1. Light-Dependent Reactions
a. Light dependent reactions produce oxygen
gas and convert ADP into energy carrier ATP
a. Water is split to produce H+ and O2 (oxygen)
b. Light energy is converted into chemical bond
energy (ATP and NADPH)
8-3 Calvin Cycle
2. The Calvin Cycle
CO2 Enters the Cycle
a.The Calvin Cycle uses energy from the lightdependent reactions to make sugars
b.As photosynthesis continues, the Calvin Cycle
runs, producing sugars while removing carbon
dioxide from the atmosphere
Energy Input
ChloropIast
5-Carbon
Molecules
Regenerated
6-Carbon Sugar
Produced
Sugars and other compounds
Figure 8-7 Photosynthesis: An
Overview
Section 8-3
Light
CO2
Chloroplast
Chloroplast
NADP+
ADP + P
LightDependent
Reactions
Calvin
Cycle
ATP
NADPH
O2
Go to
Section:
Sugars
Concept Map
Section 8-3
Photosynthesis
includes
Lightdependent
reactions
Calvin cycle
use
take place in
Energy from
sunlight
Thylakoid
membranes
to produce
ATP
NADPH
O2
takes place in
Stroma
uses
ATP
NADPH
of
to produce
Chloroplasts
High-energy
sugars