Chapter 8 Photosynthesis

1
Chapter 8 Photosynthesis
2
Saving for a Rainy Day
Interest Grabber
Section 8-1

• 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

• 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 --gt ADP) ENERGY
  RELEASED
• ADP can be recharged by adding a third
  phosphate to it (ADP --gt ATP) ENERGY STORED

Ribose
Adenosine
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
Trapping Energy
Interest Grabber
Section 8-2

• 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
  plants 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
A Look Into the Future
Interest Grabber
Section 8-3

• 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

16
(No Transcript)
17
Concept Map
Section 8-3
Photosynthesis
includes
takes place in
uses
use
take place in
to produce
to produce
of
18
Factors Affecting Photosynthesis

• Water - shortage of water can slow or even stop
  photosynthesis
• Temperature - photosynthesis depends on enzymes
  that function best between 0C and 35C
• 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
Chloroplast
Chloroplast
NADP
ADP P
Light- Dependent Reactions
Calvin Cycle
ATP
NADPH
20
Video Contents
Videos

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

21
Video 1
Video 1
ATP Formation

• Click the image to play the video segment.

22
Video 2
Video 2
Photosynthesis

• Click the image to play the video segment.

23
Video 3
Video 3
Light-Dependent Reactions, Part 1

• Click the image to play the video segment.

24
Video 4
Video 4
Light-Dependent Reactions, Part 2

• Click the image to play the video segment.

25
Video 5
Video 5
Calvin Cycle

• Click the image to play the video segment.

26
Internet
Go Online

• ATP activity
• Interactive test
• For links on Calvin cycle, go to www.SciLinks.org
  and enter the Web Code as follows cbn-3082.
• For links on photosynthesis, go to
  www.SciLinks.org and enter the Web Code as
  follows cbn-3083.

27
Section 1 Answers
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.

28
Section 2 Answers
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
  plants 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.

29
Section 3 Answers
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.

30
End of Custom Shows

• This slide is intentionally blank.