GRADE: Sixth

CONTENT STANDARD: Environmental Science

CONTENT TOPIC: Populations and Ecosystems

CONCEPT: Photosynthesis and cellular respiration are life-sustaining plant processes.

CONTENT OBJECTIVE: 6G1.00 To understand how the process of photosynthesis changes sunlight into stored chemical energy by producers

INSTRUCTIONAL OBJECTIVES: The learner will:

1.01 define photosynthesis.
1.02 analyze the process of photosynthesis.
1.03 explain the importance of photosynthesis in the life process.
1.04 define cellular respiration.
1.05 illustrate how food is broken down to release energy.
1.06 compare respiration and photosynthesis to determine how they complement each other.

I. Photosynthesis
A. Define
B. Analyze the process
II. Life process - Photosynthesis
A. Importance
B. Oxygen
C. Carbon dioxide
III. Define cellular respiration
IV. Show how food is broken down to release energy
V. Respiration and photosynthesis compares
VI. Respiration and photosynthesis complement each other

TN COMPONENT OF SCIENCE: Unifying Concepts of Science

TN GOAL:

To enable students to acquire scientific knowledge by applying concepts, theories, principles and laws from life/environmental, physical, and earth/space science.

2.1 SCALE AND MODEL - The development of models provides a conceptual bridge between the concrete and the abstract, while the use of scales allows for a comparison of differences in magnitude between the model and the desired form.

2.1c Models are often used to study processes that happen too slowly, too quickly, or on too small or too large a scale to observe directly.

BENCHMARK Models are often used to represent processes that cannot be directly observed.

TIME REQUIRED:

Lesson I - 45 minutes; Lesson II - 30 minutes; Lesson III - two one-hour instructional periods



Lesson One (This lesson addresses Objectives 1.01, 1.02, and 1.03.)

Hand lens, small test tube, beaker - 100 ml or larger, water plants, candles, jars, test, video tape

Stand up and take a deep breath. What did you breath in? (Oxygen) Today we will be studying the chemical process involved in the making of oxygen called photosynthesis. You will be expected to explain how important this chemical process is in your life.

(Do not make this lesson too in-depth. Use the lesson with relationship to the importance of photosynthesis to human life.)

Photosynthesis is the chemical change that produces food and oxygen in green plants. It is the process of making food by using sunlight. Plants must have chlorophyll (Green pigment) for photosynthesis to take place. Chlorophyll captures the sun's energy which is needed to produce sugar from carbon dioxide. Photosynthesis happens when green plant cells use water, carbon dioxide, and light to make oxygen, food, and waste products. Photosynthesis takes place in the leaf of the plant. Photo means light, synthesis means combine with light.

When does photosynthesis take place? When green plant cells make oxygen, food, and waste What is made? (Oxygen and energy)

When plants photosynthesize, they give off oxygen. People need oxygen to live. When we exhale, we give off a gas called carbon dioxide. Our bodies do not use this, but plants do for use during photosynthesis. The equation for photosynthesis is carbon dioxide + water + light and energy/chlorophyll --(sugar + oxygen.) (Show a chart with this formula.) Plants provide oxygen to people and animals through photosynthesis. Plants purify the air by taking out carbon dioxide.

Why is photosynthesis so important? (It starts the process of food for all animals and produces oxygen for us to breathe.) Animals take in oxygen and give off carbon dioxide as they breathe. Plants remove carbon dioxide from the air and add oxygen during photosynthesis. About 90% of the oxygen in the air comes from algae.

Materials: small test tube, 100 ml beaker, leaf from water plant, hand lens. (water plant can be found in ponds, aquarium shops, etc.) Keep plant in water until you are ready to do the experiment. Cut off a leaf on top of the plant and submerge in a test tube. Fill the test tube completely with water. Fill a beaker 3/4 full. Cover test tube with finger and submerge with open end of test tube in water. Place the beaker in sunlight for at least 20 minutes. Examine the leaf inside the test tube with the hand lens. Notice the bubbles of oxygen on the leaf.

(These questions could be used as an independent practice.)

1. What green substance or pigment do plants have that makes photosynthesis possible?

2. For photosynthesis to take place, plants must have __________.

Circle all that apply: sunshine, extended periods of darkness, chlorophyll, groups of other plants, carbon dioxide, pollination, water

3. Draw your own picture showing the process of photosynthesis following these directions:

a. Draw a line for the ground
b. Draw a tree going up from the ground line
c. Draw a root system for the tree
d. Next to the root system, write the following information: "Water and minerals from the soil travel through the roots and stems of plants to mix with chlorophyll and the green leaves"
e. Next to the trunk, write the following information: "The green leaves absorb light energy the sun. Leaves also take in carbon dioxide from the air. The water and minerals combine with carbon dioxide, chlorophyll and sunlight to produce sugar and oxygen. The glucose is the food manufactured by green plants"
f. Draw arrows, going up from the roots, to the top of the tree trunk
g. From the leaves on the tree top, draw an arrow pointing out of the tree and write "oxygen"
h. Draw an arrow pointing into leaves and write "carbon dioxide"
i. Draw a sun with arrows pointing out from it and write "light energy from the sun"

4. Explain the importance of photosynthesis in the life process.

5. If algae provides 90% of the oxygen in the air, what conclusion can be drawn concerning the millions of gallons of oil that have been spilled in our oceans in the past year?

In our lesson today, we have learned about the process of photosynthesis. On a sheet of paper write the process of photosynthesis. (Carbon dioxide + water + light and energy/chlorophyll ---> sugar + oxygen)

Lesson Two (This lesson addresses Objectives 1.04, and 1.05.)

Paper and markers for making charts or diagrams, resource books

What two gases are given off in the food-making processes of photosynthesis? Carbon dioxide and oxygen. Today, we will study the process that takes these gases and produces energy in plants. This process is called respiration.

Plants store some of their sugar they made during photosynthesis to give their own cells energy. They need this energy to live. This energy is made form food and oxygen inside the cell taken in through the opening of the leaves called STOMATES. The oxygen slowly combines with the sugar in the cells of the plant to produce the plant's energy. Carbon dioxide and water are given off as waste products. This process is called respiration. The plants use this energy from respiration to carry on life's activities. When you eat vegetables or fruit, both of which come from green plants, you get energy for your daily energy.

Draw your own picture showing the carbon dioxide cycle. (As teacher reads out instruction, students will write.)

l. Draw a circle.
2. In the bottom of the circle, write carbon dioxide.
3. On the right hand side of the circle draw a plant.
4. Draw an arrow pointing from the words carbon dioxide to the plant.
5. In the top of the circle, write oxygen.
6. Draw an arrow from the plant pointing toward the word oxygen.
7. Draw an animal in the left hand side of the circle.
8. Draw an arrow from the word oxygen pointing to the animal.
9. Draw an arrow from the animals to the words carbon dioxide.

We know that respiration goes on continually in all cells. Tell your neighbor what happens during respiration. It is a process by which plants break down food to make energy. (Optional) List the major differences between respiration and photosynthesis. From the carbon dioxide model, where does it show the arrow from the carbon dioxide is coming from on the chart. (animals)

1. Demonstrate, through a drawing, the cycle of respiration.

2. Have students contract photosynthesis and respiration by making charts or diagrams. Use resource books if necessary.

Lesson Three (This lesson addresses Objective 1.06.)

Chalkboard, chart

Name the two processes which keep the oxygen-carbon dioxide cycle going. (Respiration and photosynthesis) Today, we will compare these processes. You will be expected to tell how they compliment each other.

We have learned that during photosynthesis a plant used sunlight to produce sugar. During respiration the plant turns this sugar to energy. Carbon dioxide and water are used to make food in photosynthesis. Both substances are produced in respiration. During photosynthesis, energy is stored in the food made. In respiration, energy is released from food to be used by a cell. The process respiration is the opposite of photosynthesis.

Make a comparison chart of photosynthesis and respiration: During the process of photosynthesis:

1. Photosynthesis takes place only in cells with chlorophyll.
2. Carbon dioxide is taken in.
3. Water is taken in.
4. Food (Sugar) is made.
6. Oxygen is given off.

During the process of respiration

1. Respiration takes place in all cells.
2. Food (Sugar) is broken down.
3. Oxygen is used.
4. Energy stored in sugar is released.
5. Carbon dioxide is produced and given off.
6. What is produced and given off.

(Check responses and use the summary above to help the students summarize.)

(Discuss - When people and animals breathe, they take in oxygen and give off carbon dioxide. Respiration takes place within the cells of all living things.)

Using your comparison list, write the equation for photosynthesis and respiration.

(1. RESPIRATION: sugar + oxygen ---->energy + carbon dioxide + water

2. PHOTOSYNTHESIS: water + carbon dioxide + energy ---> sugar + oxygen. They are entirely opposite but they do complement each other.)

Monitor: Check their responses.

We have discussed some processes between photosynthesis and respiration. (Pause, then summarize) Tell your neighbor the difference between respiration and photosynthesis.

1. We know that the oxygen-carbon dioxide cycle repeats itself over and over again. Make a cycle strip

a. Make the first square of your cycle strip- Plants breathe in carbon dioxide.
b. Second square-Water is taken in.
c. Fourth square- Sun's energy is stored in sugar.
d. Fifth square-Oxygen is given off.
e. Sixth square-We breathe in oxygen and eat food.
f. Seventh square-Energy stored in sugar is released.
g. Eighth square-Carbon dioxide is produced and given off
h. Cut out strip and tape the first square to the bottom of the eighth square
i. The student could paste onto a can or small box if available. The strip can be turned until the cycle repeats itself over and over.

Choose two or more of the remaining activities below:

2. How does the cutting of large forests to build subdivisions and shopping centers affect the oxygen-carbon dioxide cycle and life in general?

3. Develop criteria for zoning land for preservation.

4. What do you think will happen if we continue to cut down trees at the rate we are now destroying forest?

5. Plan a model city of the future where all the natural resources are preserved.

This is the time this file has been accessed since 02/25//98.

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