8.2-3 photosynthesis.ppt

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Lesson Overview

Photosynthesis: An Overview

THINK ABOUT IT

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Lesson Overview

Photosynthesis: An Overview

What is

Photosynthesis?

1. What is the photosynthesis equation? Pg. 232 What

are the reactants and what are the products?

2. Why do leaves appear green? Why are they red and

orange in the Fall?

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Lesson Overview

Photosynthesis: An Overview

8.2 Photosynthesis

=

using light energy to make carbon

compounds (sugar).

It requires special solar collectors called

chloroplasts

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Lesson Overview

Photosynthesis: An Overview

Chlorophyll and Chloroplasts

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Lesson Overview

Photosynthesis: An Overview

Chlorophyll and Chloroplasts

Photosynthetic organisms

capture energy from

sunlight with pigments.

Pigments are located in the chloroplast’s

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Lesson Overview

Photosynthesis: An Overview

How do the

pigments

collect light?

The

sun

sends out electromagnetic energy

.

Humans can only see

the

visible light

of the electromagnetic energy or spectrum.

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Lesson Overview

Photosynthesis: An Overview

Visible Light

Our eyes see the different wavelengths of the

visible spectrum as different colors: red, orange,

yellow, green, blue, indigo, and violet.

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Lesson Overview

Photosynthesis: An Overview

Pigments

The plant has different pigments to collect the sunlight

at different wavelengths

.

i.e. two types of chlorophyll, chlorophyll

a

and chlorophyll

b

, absorb light very well in the blue-violet and red

regions of the visible spectrum, but not in the

green

region, as shown in the graph.

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Lesson Overview

Photosynthesis: An Overview

Pigments

Plants

also contain red and orange pigments

such as carotene that absorb light in other

regions of the spectrum

.

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Lesson Overview

Photosynthesis: An Overview

Pigments

Most of the time, the green color of the

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Lesson Overview

Photosynthesis: An Overview

Inquiry-Why are plants

green

?

Follow the instructions on your paper and graph the

data, then answer the analysis questions.

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Lesson Overview

Photosynthesis: An Overview

Option 1:

Does

Elodea take in

or give off CO

₂

?

Photosynthesis Lab

Option 2:

Does

Elodea take in

CO

₂

in the dark?

Dark

Light

Option 3:

Does

Elodea give off

CO

₂

in the dark?

Dark

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Lesson Overview

Photosynthesis: An Overview

Photosynthesis Lab

1. Title and Name!

2. Purpose: Option 1, 2, or 3

3. Hypothesis: If…then…because…

4. Materials: Elodea, Bromthymol Blue solution, test tubes, foil, lamps

5. Procedure: Write out how you would do your experiment in

numbered steps. List control, independent and dependent

variable, and constants.

6. Data: Observation

7. Analysis: Answer your question from above. How did you know?

8. Conclusion

a) Did you prove your hypothesis?

b) What went wrong in your experiment? What could you

improve?

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Lesson Overview

Photosynthesis: An Overview

Warm up

1. Why do leaves appear green? Why are they

red and orange in the Fall?

2. Draw & label a carbon atom. Atomic number

=6

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Lesson Overview

Photosynthesis: An Overview

Energy Collection

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Lesson Overview

Photosynthesis: An Overview

Chromatography

Problem: What pigments are in leaves? Hypothesis: State if…then

Procedure: With your table buddy, get one lab set up

On each of the filter paper draw a PENCIL line across the one edge Place a spinach leaf over the pencil line and roll a washer over the line

Repeat with the cabbage line an another piece of filter paper Place both papers in your beaker with 25 ml of alcohol

DO not let the pigment line touch the alcohol-only the paper edge touches. Watch the alcohol line carefully.

Remove when the line reaches the top of the beaker Data: See Doc camera

Conclusions:

1. How many and what pigment bands did you see for each leaf? 2. How do the two leaf bands compare?

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Lesson Overview

Photosynthesis: An Overview

High-Energy Electrons

high-energy electrons produced by chlorophyll are highly

reactive and require a special “carrier.”

What are electron carriers?

compounds that can accept a pair of

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Lesson Overview

Photosynthesis: An Overview

High-Energy Electrons

Think of a high-energy electron as being similar to a hot

potato. If you wanted to move the potato from one place to

another, you would use an oven mitt—a carrier—to transport

it.

Plants use electron carriers to transport

high-energy electrons from chlorophyll to other

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Lesson Overview

Photosynthesis: An Overview

High-Energy Electrons

NADP

+

(nicotinamide adenine dinucleotide

phosphate)

is an electron carrier molecule

.

NADP

+

accepts and holds two high-energy

electrons, along with a hydrogen ion (H

+

). It is

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Lesson Overview

Photosynthesis: An Overview

An Overview of Photosynthesis

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Lesson Overview

Photosynthesis: An Overview

An Overview of Photosynthesis

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Lesson Overview

Photosynthesis: An Overview

Light-Dependent Reactions

Photosynthesis involves two sets of reactions.

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Lesson Overview

Photosynthesis: An Overview

Light-Dependent Reactions

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Lesson Overview

Photosynthesis: An Overview

Light-Independent Reactions

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Lesson Overview

Photosynthesis: An Overview

Photosynthesis Big Picture

Needed to make food

Uses

Pigments, H2O, CO2, sunlight

2 Reactions

Dependent

Independent

Needs:

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Lesson Overview

Photosynthesis: An Overview

Photosynthesis Big Picture

Needed to make food

Uses

Pigments, H2O, CO2, sunlight

2 Reactions

Dependent

Independent

Needs: light, water, NADP

Needs: ATP, CO2, NADPH