1. Chapter 8 Photosynthesis

2. Interest Grabber Saving for a Rainy Day
Section 8-1
Saving for a Rainy Day
Suppose you earned extra money by having a part-time 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?

3. Energy and Life Autotrophs Heterotrophs
Plants and some other types of organisms are able to use light energy from the sun to produce food
Heterotrophs
organism that obtains energy from the
foods it consumes;
also called a consumer

4. Chemical Energy and ATP
Living things use chemical fuels.
ATP (adenosine triphosphate) is the main chemical compound used to store and release energy in cells
The energy stored in ATP is released by breaking the third phosphate bond (ATP --> ADP) ENERGY RELEASED
ADP can be “recharged” by adding a third phosphate to it (ADP --> ATP) ENERGY STORED
Adenosine
Ribose
3 Phosphate groups

5. Figure 8-3 Comparison of ADP and ATP to a Battery
Section 8-1
ADP
ATP
Energy
Energy
Adenosine diphosphate (ADP) + Phosphate
Adenosine triphosphate (ATP)
Partially
charged
battery
Fully
charged
battery

6. Figure 8-3 Comparison of ADP and ATP to a Battery
Section 8-1
ADP
ATP
Energy
Energy
Adenosine diphosphate (ADP) + Phosphate
Adenosine triphosphate (ATP)
Partially
charged
battery
Fully
charged
battery

7. Using Biochemical Energy
What are some ways that ATP is used in a cell?
Active transport (energy requiring) ion pumps
Protein synthesis at ribosomes
ATP can be used to produce light - fireflies
Cells do not have large stores of ATP
Long term storage of energy is in the form of glucose
1 molecule of glucose has 90 times the energy of one ATP

8. Interest Grabber Trapping Energy
Section 8-2
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.

9. Interest Grabber continued
Section 8-2
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?

10. Investigating Photosynthesis
The experiments performed by van Helmont, Priestley, and Ingenhousz led to work by other scientists who finally discovered that in the
presence of light, plants transform
carbon dioxide and water into carbohydrates, and they also release oxygen.

11. Photosynthesis: Reactants and Products
Section 8-2
Light Energy
Chloroplast
CO2 + H2O
Sugars + O2

12. The Photosynthesis Equation
Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into high-energy sugars and oxygen.

13. Figure 8-5 Chlorophyll Light Absorption
Section 8-2
Light and Pigment
In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll, a molecule in chloroplasts.
Plants gather the sun's energy with light-absorbing molecules called pigments.
The plants' principal pigment is chlorophyll There are two main types of chlorophyll: chlorophyll a and chlorophyll b.

14. Interest Grabber A Look Into the Future
Section 8-3
A Look Into the Future
It is 100 years in the future and you are a research scientist. An enormous volcanic eruption has recently sent huge quantities of dust and ash into the atmosphere.
Working with a partner, make a list of how this event will affect each of the following:
1. photosynthesis
2. plant life
3. animal life
4. human societies

15. The Reactions of Photosynthesis
Photosynthesis takes place inside chloroplasts
The chloroplasts contain saclike photosynthetic membranes called thylakoids.
Thylakoids are arranged in stacks called grana
Proteins in the thylakoid membrane organize chlorophyll and other pigments into photosystems.
Photosystems are the light collecting unit of the chloroplasts

17. Concept Map Photosynthesis Light- dependent reactions Calvin cycle
Section 8-3
Photosynthesis
includes
Light-
dependent
reactions
Calvin cycle
takes place in
uses
use
take place in
Thylakoid
membranes
Stroma
NADPH
ATP
Energy from
sunlight
to produce of
to produce
ATP
NADPH O2
Chloroplasts
High-energy
sugars

18. Factors Affecting Photosynthesis
Water - shortage of water can slow or even stop photosynthesis
Temperature - photosynthesis depends on enzymes that function best between 0°C and 35°C
Light Intensity - increasing light intensity increases the rate of photosynthesis, however at a certain intensity plants hit a maximum rate

19. Figure 8-7 Photosynthesis: An Overview
Section 8-3
Light O2
Sugars
CO2
Chloroplast
Chloroplast
NADP+
ADP + P
Light-
Dependent
Reactions
Calvin
Cycle
ATP
NADPH

20. Click a hyperlink to choose a video. ATP Formation Photosynthesis
Videos
Click a hyperlink to choose a video.
ATP Formation
Photosynthesis
Light-Dependent Reactions, Part 1
Light-Dependent Reactions, Part 2
Calvin Cycle
Video Contents

21. Click the image to play the video segment.
ATP Formation
Click the image to play the video segment.
Video 1

22. Click the image to play the video segment.
Photosynthesis
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Video 2

23. Click the image to play the video segment.
Light-Dependent Reactions, Part 1
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Video 3

24. Click the image to play the video segment.
Light-Dependent Reactions, Part 2
Click the image to play the video segment.
Video 4

25. Click the image to play the video segment.
Calvin Cycle
Click the image to play the video segment.
Video 5

26. Go Online ATP activity Interactive test
For links on Calvin cycle, go to and enter the Web Code as follows: cbn-3082.
For links on photosynthesis, go to and enter the Web Code as follows: cbn-3083.
Internet

27. Interest Grabber Answers
1. What are the benefits of having a bank account?
To save money and earn interest.
2. What do you have to do if you need some of this money?
Go to the bank and take out the money you need.
3. What might your body do when it has more energy than it needs to carry out its activities?
Students will likely say that the body stores the energy.
4. What does your body do when it needs energy?
Student answers may include that energy is gotten from food.
Section 1 Answers

28. Interest Grabber Answers
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?
They convert light energy into electrical energy.
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?
Plants convert light energy into chemical energy.
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?
Leaves are green, as are some stems.
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?
The green color is the pigment chlorophyll, which absorbs light energy from the sun and converts it to chemical energy in the process of photosynthesis.
Section 2 Answers

29. Interest Grabber Answers
Working with a partner, make a list of how this event will affect each of the following:
1. photosynthesis The rate of photosynthesis will decrease due to reduced sunlight.
2. plant life Plants will grow more slowly or die off due to decreased rate of photosynthesis.
3. animal life Animal populations will decrease after a while due to fewer plants for herbivores to eat. Fewer herbivores will eventually result in fewer carnivores. Also, less oxygen will be available.
4. human societies Human societies will have to adjust their eating habits as some food species die out.
Section 3 Answers

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