INTERACTIVE GENETICS

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Cell Energy
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When do you use energy?List all of the ways you
have used energy today.
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• Without the ability to obtain and use energy,
  life would not exist.

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Forms of Energy

• Energy comes in many forms
• Light
• Heat
• Electricity
• . . . Energy can also be stored in the bonds of
  chemical compounds.

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2 types of energy in living things

• Autotrophs- organisms that get their energy
  directly from the sun.
• Examples
• Heterotroph- Organisms that eat food to obtain
  their energy.
• Examples
• ALL energy begins with the sun!
• How does a heterotroph get energy from the sun?

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Chemical Energy

• The main compound cells use to store and release
  energy ATP

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1. ATP
adenosine triphosphate
ATP is a high energy compound
2. ADP... adenosine diphosphate (1-less phosphate
group and less stored energy)
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Complete ATP Worksheet!
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Important Scientists

• Van Helmont-
• - Wondered if plants grew by taking mass out of
  the soil?
• - Measured the soil, planted a seed and watered
  the plant until it grew.
• - After 5 years, plants weighed 75 kg and the
  soil was unchanged!
• Concluded- water (hydrate) that made the plant
  grow!

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Another Scientist

• Priestley-
• Light a candle, put a glass jar over it
• Candle goes out immediately!
• Second time lit a candle with a sprig of fresh
  mint
• Candle burned for much longer than without mint.
• Why?
• Mint produces oxygen- necessary to burn!

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Last Scientist

• Ingenhousz-
• Added to Priestlys experiment
• Concluded that plant must be exposed to light in
  order for Priestly effect to work.
• No light, no photosynthesis!

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• The two cell energy processes we will discuss
• Photosynthesis
• Cellular Respiration

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TO DO

• In your notebook write the following equations.
• 1. Show ATP breaking down to ADP
• 2. Show ADP capturing energy to make ATP

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TO DO 2

• Write the following equations in your notebook.
  (should use a new page)
• 1. Write the chemical equation for
  photosynthesis
• 2. Write the photosynthesis equation out in
  words.
• 3. Write the photosynthesis equation out in
  pictures. Be sure to add color!

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Photosynthesis
CHAPTER 8 PAGE 201
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Photosynthesis

• Definition The conversion of light energy into
  chemical energy stored in organic compounds

Who can do this? Plants and Algae
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Chemical Equation
In other words, remember this carbon dioxide
water light energy glucose oxygen As a
chemical reaction it's like so 6CO2 6H2O
C6H12O6 6O2
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Photosynthesis Equation

• Learn the song! It will help!
• On a separate sheet of paper
• (next page of notes)
• 1. Write the chemical equation for
  photosynthesis
• 2. Write the equation for photosynthesis out in
  words
• 3. Write out the equation for photosynthesis
  in pictures! Use the colored pencils!

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Where does it happen?

• Within the CHLOROPLAST of a plant cell

Draw label in notes!
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• Photosynthesis begins with the absorption of
  light by pigments in the thylakoids
• Main pigments in plants chlorophyll. It
  absorbs all colors of light, and reflects back
  green.

PIGMENTS
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Light and Pigments

• In addition to water and carbon dioxide,
  photosynthesis requires light and chlorophyll.
• Chlorophyll is found in chloroplast! (green)
• Plants gather the suns light in pigments.
  (light absorbing molecules)
• Since light is a form of energy, anything that
  absorbs light is also absorbing energy!

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Chlorophyll Absorption

• Complete handout activity on chlorophyll
  absorption!

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DO NOW Pigments

• 1. Write the balanced chemical equation for
  photosynthesis.
• 2. What pigment does the chloroplast contain?
• 3. What does the pigment do in a plant?

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Photosynthesis Lab

• 1. Use your textbook, page 206 for setup
  instructions.
• 2. Once your lab group has your lab set up
  please return to your seats. Be sure to leave
  your lab area clean!
• 3. After we return to your lab answer questions
  1-3.

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How does it happen????
2 Major Groups of Reactions
A. Light Dependent B. Calvin Cycle
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Photosynthetic Processes

• Light Reactions- Trap the energy from sunlight.
• Calvin Cycle- use energy from light reactions to
  produce sugars. Carbon Dioxide and Water are
  needed with light, sugar is produced and oxygen
  given off! (remember equation)

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A. Light Reactions

1. Reaction occurs in the membrane of the thylakoid

Chloroplast
Circle on the diagram you drew.
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A. Light Reactions-cont
2. Light excites e- in chlorophyll pigments (e-
go from low energy to high energy)
3. e- travel to other molecules in membrane,
losing energy along the way
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This process is called THE ELECTRON TRANSPORT CHAI
N (ETC)
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Final Step4. e- combine to make ADP
phosphate e- ATP When
the bond in ATP is broken, energy is released!
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Summary of Light Reactions...
Needed Light energy H2O Made ATP, H Waste
Oxygen
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TO DO Photosynthesis

• What is the complete chemical equation for
  photosynthesis?
• Where does photosynthesis take place
• What organelle?
• What part of the organelle?
• Light Reactions-
• Dark Reactions-
• What is formed when electrons share their energy
  with other electrons?

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B. Calvin Cycle
produces glucose
(a.k.a. Dark Reaction)

1. Occurs in stroma of chloroplast (circle on your
   diagram)
2. Uses ATP and H from light rxn.
3. ATP H CO2(from air) glucose (carb)

Photosynthesis Animation!
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C h l o r o p l a s t
Solution-
STROMA
THYLAKOID
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The exchange of gases between the leaf and the
atmosphere occurs through the STOMATA
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Summary
Light Reaction Makes ATP from ADP
Calvin Cycle Makes glucose
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Factors Affecting Photosynthesis

1. Water amounts- Shortage of water can slow down or
   stop the rate of photosynthesis.
2. Temperature- Photosynthesis likes to occur
   between 0-35 Celsius.
3. Intensity of Light- not enough light, no
   photosynthesis. Every plant needs a different
   amount of light.