Go to Section : 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
Transcript
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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
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8-1 Energy and Life
-ATP is the universal “currency” for energy in the cell
-ATP = adenosine triphosphate
- = three phosphate groups bonded together (tri = three)
ATP, continuedAMP + P → ADP (M = mono-) (D = di- )ADP + P → ATP
ATP stores the maximum amount of energy→ ATP is like a FULL battery (maximum)→ ADP is like a HALF battery (half the energy storage capacity)→ AMP is like a DEAD or EMPTY battery (BUT it can be recharged!)
• AMP to ADP to ATP = STORES energy• ATP to ADP to AMP = RELEASES energy
Energy to make ATP comes from breaking down GLUCOSE (in mitochondria) →Glucose has up to 90 times the amount of energy in an ATP molecule
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Video 1
ATP Formation
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Energy for living things on Earth
•Most living things generate their energy directly or indirectly from the SUN =photosynthesis
•Some organisms (at hydrothermal vents or geysers or anaerobic mud) use chemical compounds (hydrogen sulfide) to make organic compounds (carbs) through chemosynthesis
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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
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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
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8–2 Photosynthesis: An OverviewA. 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
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•The Photosynthesis Equation
6CO2 + 6H2O ---(light)------- C6H12O6 + 6O2
Carbon dioxide and water (and light) make glucose and oxygen
• Light and Pigments
1. Pigments = light-absorbing molecules
2. Chlorophyll = plants’ principal pigment; absorbs light energy for the plant to use during photosynthesis
3. White light contains all colors
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Balancing The Photosynthetic Equation:
_ CO2 + _ H2O → C6H12O6 + _O2
# Carbons : 6 on the right, so how many on the left? 6!
6 Carbons on the left, so how many oxygen atoms in 6 CO2? 12!
12 Hydrogen atoms on the right, so how many water molecules on the left? (Watch out! – it’s H2O) 6!
6 CO2 molecules and 6 H2O molecules makes how many O atoms on the left?
Last step: How many O2 molecules do you need on the right, to get 18 O atoms? (Watch out! – there are 6 already in glucose!)
18!
6!
6 CO2 + 6 H2O → C6H12O6 + 6O2
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Light Energy
Chloroplast
CO2 + H2O Sugars + O2
Section 8-2
Photosynthesis: Reactants and Products
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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
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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
Section 8-3
Interest Grabber
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8–3 The Reactions of PhotosynthesisA. Inside a Chloroplast
B. Electron Carriers
C. Light-Dependent Reactions
D. The Calvin Cycle
E. Factors Affecting Photosynthesis
Section 8-3
Section Outline
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Video 2
Photosynthesis
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Chloroplast
Light
O2
Sugars
CO2
Light-Dependent Reactions
CalvinCycle
NADPH
ATP
ADP + PNADP+Chloroplast
Section 8-3
Figure 8-7 Photosynthesis: An Overview
H2OLight
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8-3 The Reactions of Photosynthesis
A. Light Dependent Reactions1. Occurs :
a. across the thylakoid membrane and in the stroma of the chloroplast
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2. Uses
a. Light energy
b. H2O
3. To make:
i. From sunii.Turns electrons into high
energy electronsiii. Drives the light reactions
i. Energy splits apart the water molecule into 2 Hydrogen+ atoms and 1 Oxygen atom
ii. O find a friend to make O2 – oxygen gas is released
iii. Extra 2e- collect sun’s energy
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c. NADP+
d. ADP
i. High energy electron carrier ii. Picks up 2 e- and a H+ to become NADPH
i. Picks up a phosphate to make ATPii. Goes on to Calvin Cycle*Light-dependent reactions use H2O
and produce O2 gas and intermediate energy-storing compounds
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4. Steps in Light Reactions
a. Sun energy gets absorbed by pigments in Photosystem II
b. This energy splits H2O into 2H+ atoms and 1 oxygen atom, leaves 2 electrons to hang out and wait in PSII
c. Sun is absorbed by the pigments, the electrons get this energy
d. Electrons become high energy electrons
e. Travel down the Electron Transport Chain (ETC), losing energy as they travel down each protein
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f. Come to Photosystem I, light gets absorbed again, electrons become high energized again
g. High energy electrons need a special “carrier” to bring them to the Calvin Cycle
h. Get picked up by NADP+, which also picks up an H+ left over from H2O
i. NADP+ + 2e- + H+ NADPH
i. High energy electron carrier
ii. Heads to Calvin Cycle
J. ADP + P ATP at the ATP Synthase
i. heads to Calvin Cycle
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HydrogenIon Movement
Photosystem II
InnerThylakoidSpace
ThylakoidMembrane
Stroma
ATP synthase
Electron Transport Chain Photosystem I ATP Formation
Chloroplast
Section 8-3
Figure 8-10 Light-Dependent Reactions
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Video 3
Light-Dependent Reactions, Part 1
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Video 4
Light-Dependent Reactions, Part 2
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B. Calvin Cycle / Light Independent Reaction / Dark Reactions
1. Takes place in:
a. Stroma – area outside of thylakoids but within the chloroplast
*Calvin Cycle -> produces carbohydrates using carbon dioxide from the atmosphere and ATP and NADPH energy-storing compounds from the light-dependent reaction
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2. Uses
a. ATP
b. CO2
c. NADPH
3. To make
i. Need energy to make glucose
ii. Gets broken back down into ADP
iii. Heads back to the light reactions to get used again there
i. Uses 6 molecules of CO2 to produce 1 molecule of glucose
i. High energy electrons help to make glucose
ii. Gets broken back down to NADP+ and returns to light reactions
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ChloropIast
CO2 Enters the Cycle
Energy Input
5-CarbonMoleculesRegenerated
Sugars and other compounds
6-Carbon SugarProduced
Section 8-3
Figure 8-11 Calvin Cycle
*Calvin Cycle -> produces carbohydrates using carbon dioxide from the atmosphere and ATP and NADPH energy-storing compounds from the light-dependent reaction
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Video 5
Calvin Cycle
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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
Videos
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ATP Formation
Photosynthesis
Light-Dependent Reactions, Part 1
Light-Dependent Reactions, Part 2
Calvin Cycle
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.
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.
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.
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.
