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1
1Ph
oto
syn
the
sis
Photosynthesis converts light energyinto chemical energy
Plants and some other
types of organisms (all of
which are autotrophes) are
able to use light energy
from the sun to produce
food2
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?
Section 8-1
Interest Grabber
3
8–1 Energy and Life
A. Autotrophs and Heterotrophs
Section 8-1
Section Outline
4
Autotrophes•These form the base of all ecosystems
•Use energy from the sun to produce
C6H12O6 (sugar/food) from CO2 + H2O
(carbon dioxide + water)
– These are called photoautotrophes
(>99% of all producers)
•Some use the energy stored in the chemical
bonds of inorganic molecules
– These are called chemoautotrophes (<
1% of all producers)
2
5
Heterotrophes
•Upper levels of trophic level pyramids are
made up of these animals, protists, some
bacteria and some fungi.
•These are the consumers – they get their
energy from food they consume (either
plants or animals)
On which trophic level do
these herbivores belong?
6
8–1 Energy and Life
A. Autotrophs and Heterotrophs
B. Chemical Energy and ATP
1. Storing Energy
2. Releasing Energy
Section 8-1
Section Outline
7
Adenine Ribose 3 Phosphate groups
Section 8-1
Parts of the ATP molecule:
8
ADP ATP
Energy
EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)
Partiallychargedbattery
Fullychargedbattery
Section 8-1
Figure 8-3 Comparison of ADP and ATP to a Battery
Storing energy by adding energy and phosphate to ADP
3
9
ADPATP
Energy
Energy
Adenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)
Section 8-1
Releasing energy by “subtracting” a phosphate from ATP
10
ADP ATP
Energy
EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)
Partiallychargedbattery
Fullychargedbattery
Section 8-1
Figure 8-3 Comparison of ADP and
ATP to a Battery
Figure 8-3 Comparison of ADP and ATP to a Battery
11
Adding energy allows a phosphate to
be added and the energy is stored in
the bond
12
8–1 Energy and Life
A. Autotrophs and Heterotrophs
B. Chemical Energy and ATP
1. Storing Energy
2. Releasing Energy
C. Using Biochemical Energy
Section 8-1
Section Outline
4
13
Using ATP in the cell
•Active transport
•Synthesis
–Proteins
–Nucleic acids
•Produce light!! 14
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.
Section 8-2
Interest Grabber
15
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?
Section 8-2
Interest Grabber continued
16
8–2 Photosynthesis: An Overview
A. Investigating Photosynthesis
1. Van Helmont’s Experiment
2. Priestley’s Experiment
3. Jan Ingenhousz
Section 8-2
Section Outline
5
17
Van Helmont’s Experiment
•In the 1600s, the Belgian physician Jan van Helmont devised
an experiment to find out if plants grew by taking material out
of the soil.
– determined the mass of a pot of dry soil and a small
seedling
– He watered it regularly. At the end of five years, the
seedling, which by then had grown into a small tree, had
gained about 75 kg
– The mass of the soil, however, was almost unchanged.
– Conclusion? That most of the gain in mass had come
from water, because that was the only thing that he had
added.
– (the carbon for carbohydrates comes from the CO2 in the
atmosphere)
18
Priestley’s Experiment
• 1771- Priestley took a candle, placed a glass jar over it, and
watched as the flame gradually died out.
– Something in the air, Priestley reasoned, was necessary
to keep a candle flame burning.
– When that substance was used up, the candle went out.
– That substance was oxygen.
•Priestley then found that if he placed a live sprig of mint under
the jar and allowed a few days to pass,
– the candle could be re-lighted and would remain lighted
for a while.
– The mint plant had produced the substance required for
burning.
– In other words, the mint released oxygen.
19
Jan Ingenhousz’s Experiment
•1779 - Dutch scientist Ingenhousz
showed that the effect observed by
Priestley occurred only when the plant
was exposed to light.
–The results of both Priestley's and
Ingenhousz's experiments showed
that light is necessary for plants to
produce oxygen. 20
8–2 Photosynthesis: An Overview
A. Investigating Photosynthesis
1. Van Helmont’s Experiment
2. Priestley’s Experiment
3. Jan Ingenhousz
B. The Photosynthesis Equation
C. Light and Pigments
Section 8-2
Section Outline
6
21
What is the basic equation for
photosynthesis?
6H2O + 6CO2 C6H12O6+ 6O2Water plus carbon dioxide plus light yield sugar and oxygen
22
Light Energy
Chloroplast
CO2 + H2O Sugars + O2
Section 8-2
Photosynthesis: Reactants and Products
23
Absorption of Light byChlorophyll a and Chlorophyll b
V B G YO R
Chlorophyll b
Chlorophyll a
Section 8-2
Figure 8-5 Chlorophyll Light Absorption
24
B
A
This is the visible spectrum
of light (what we can see)
(One billionth (10-9) of a meter)
7
26
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.
In your notes, make a list of how this event will affect each of the following:
1. photosynthesis
2. plant life
3. animal life
4. human societies
Section 8-3
Interest Grabber
27
8–3The Reactions of Photosynthesis
A. Inside a Chloroplast
Section 8-3
Section Outline
28
Structure of Chloroplast
Thylakoid
Stroma
Grana
Inner membraneouter membrane
29
8
30 31
32
Chloroplast
Light
O2
Sugars
CO2
Light-Dependent Reactions
CalvinCycle
NADPH
ATP
ADP + P
NADP+Chloroplast
Section 8-3
Figure 8-7 Photosynthesis: An Overview
Video 3
Click the image to play the video segment.
Light-Dependent Reactions, Part 1
9
Video 4
Click the image to play the video segment.
Light-Dependent Reactions, Part 2
35
8–3The Reactions of Photosynthesis
A. Inside a Chloroplast
B. Electron Carriers
Section 8-3
Section Outline
NADP+ +2e- + H+ NADPH
NADPH
36
NADPH carries
high energy
electrons
(ATP is a more
stable
molecule used
for cellular
processes) 37
Photosynthesis
includes
of
take place intakes place in uses
to produce to produce
use
Light-dependentreactions
Calvin cycle
Thylakoidmembranes Stroma NADPHATPEnergy from
sunlight
ATP NADPH O2 Chloroplasts High-energysugars
Section 8-3
Concept Map of the rxns of photosynthesis
CO2H2O
10
38
8–3The Reactions of Photosynthesis
A. Inside a Chloroplast
B. Electron Carriers
C. Light-Dependent Reactions
Section 8-3
Section Outline
39
Hydrogen
Ion MovementPhotosystem II
Inner
Thylakoid
Space
Thylakoid
Membrane
Stroma
ATP synthase
Electron
Transport ChainPhotosystem I ATP Formation
Chloroplast
Section 8-3
Figure 8-10 Light-Dependent Reactions
40
8–3The Reactions of Photosynthesis
A. Inside a Chloroplast
B. Electron Carriers
C. Light-Dependent Reactions
D. The Calvin Cycle
Section 8-3
Section Outline
41
ChloropIast
CO2 Enters the Cycle
Energy Input
5-Carbon
Molecules
Regenerated
Sugars and other compounds
6-Carbon Sugar
Produced
Section 8-3
Calvin Cycle
11
Video 1
Click the image to play the video segment.
ATP Formation
Video 5
Click the image to play the video segment.
Calvin Cycle
44
8–3The Reactions of Photosynthesis
A. Inside a Chloroplast
B. Electron Carriers
C. Light-Dependent Reactions
D. The Calvin Cycle
E. Factors Affecting Photosynthesis
Section 8-3
Section Outline
45
Factors Affecting Photosynthesis:
light intensity
12
46
Factors Affecting Photosynthesis:
Temperature
47
Factors Affecting Photosynthesis:
CO2 concentration & water
Video Contents
Follow up:
Fill in Concept Map (due at end of period)
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